Abstract

Background Post-term birth, defined every bit nascency after pregnancy elapsing of 42 weeks, is associated with increased neonatal morbidity and mortality. The long-term consequences of post-term birth are unknown. Nosotros assessed the clan of post-term nascence with problem behaviour in early babyhood.

Methods The study was performed in a big population-based prospective cohort written report in Rotterdam, The Netherlands. Meaning mothers enrolled between 2001 and 2005. Of a cohort of 5145 children, 382 (7%) were born post-term, and 226 (iv%) were built-in preterm. Parents completed a standardized and validated behavioural checklist (Kid Behavior Checklist, CBCL/1.five–5) when their children were one.five and 3 years former. Nosotros examined the relation between gestational historic period (GA) at nascence, based on early fetal ultrasound examination, and problem behaviour with regression analyses, adjusting for socio-economic and pregnancy-related confounders.

Results A quadratic relationship between GA at nascence and problem behaviour indicates that both preterm and mail service-term children have higher behavioural and emotional problem scores than the term born children. Compared with term born children, post-term born children had a higher run a risk for overall problem behaviour [odds ratio (OR) = 2.10, 95% confidence interval (CI) = 1.32–3.36] and were almost two and a half times as likely to accept attention deficit / hyperactivity problem behaviour (OR = 2.44, 95% CI = 1.38–iv.32).

Conclusions Mail-term birth was associated with more than behavioural and emotional problems in early childhood, especially attending deficit / hyperactivity problem behaviour. When considering expectant direction, this aspect of post-term pregnancy should be taken into business relationship.

Introduction

Timely onset of labour is important for peri- and mail service-natal health. Both preterm (<37 weeks of gestation) and post-term birth (≥42 weeks of gestation) are associated with neonatal morbidity and mortality. 1 – 3 Local direction protocols with regard to elective caesarean delivery and labour induction affect the prevalence of post-term birth. Overall, labour induction before or at 42 weeks of gestation has increased, 1 just post-term births even so occur relatively ofttimes (upwards to five–10%), even in industrialized countries. three , 4 Accurate pregnancy dating is disquisitional to the diagnosis of postal service-term births. 3 , 4 Routine use of ultrasound to confirm pregnancy dating can subtract occurrence of mail-term birth. 5 Common take chances factors for post-term birth include obesity, nulliparity and prior mail service-term birth and rare causes include placental sulphatase deficiency (an X-linked recessive disorder characterized by depression estriol levels), fetal adrenal hypoplasia or insufficiency and trisomy 16 and 18. 1 , two , 6 , 7

The long-term problems associated with preterm birth, such as increased incidence of cerebral palsy, sensory impairments and behavioural problems are well known. 8 The studies investigating effects of mail-term nascence have focused on the risks during pregnancy and delivery. ix Post-term birth increased the adventure of neonatal encephalopathy and death during the first year of life, v , x just the long-term consequences are unclear. One of the few studies performed establish that post-term born infants did not differ from controls at historic period 2 years regarding general intelligence, physical milestones and illnesses. 11 However, a recent study using referral to a neurologist or psychologist as indicator of developmental problems found that thirteen% of children born post-term had a neurological or developmental disorder at the historic period of five years. 12

In this population-based prospective study, nosotros hypothesize that post-term birth is related to behavioural and emotional problems in preschool children. In gild to examine the specificity of the association between post-term nativity and problem behaviour, we examined specific behavioural and emotional bug including attention arrears / hyperactivity disorder issues (ADHD), affective problems and pervasive developmental problems.

Materials and methods

This study was embedded within the Generation R Study, a population-based cohort from fetal life onwards. 13 Briefly, significant women who were resident in Rotterdam, The Netherlands, and whose delivery dates were between Apr 2002 and Jan 2006, were asked by their midwives and gynaecologists to participate. In the mail service-natal follow-up of the Generation R cohort, 7484 live born children and their prenatally recruited mothers participated. Mail service-natally, 38 children died. The remaining 7446 children were eligible for the study. Mothers of 477 children withdrew consent, and mothers of 410 children gave restricted consent (i.e. no participation in questionnaire studies). The remaining mothers of 6559 children gave full consent for post-natal follow-upward. We excluded twin pregnancies, leaving 6422 children who could exist contacted. Data on child behavioural and emotional problems at 18 and/or 36 months was available for 5145 children (response charge per unit of 78%). Maternal report at both 18 and 36 months was available for 3840 children, 812 mothers reported at 18 months just and 493 mothers reported at 36 months only. The Medical Ethical Review Lath of the Erasmus Medical Centre, Rotterdam approved the written report protocol. All parents of participating children gave written informed consent.

Ultrasound during the starting time visit determined gestational age (GA) to the nearest 24-hour interval, which will be expressed in our analyses in weeks. In total, 4132 women (fourscore%) had their outset ultrasound examination in early pregnancy (median thirteen.1 weeks, range 5.one–18.0), 868 women (17%) had information technology in mid-pregnancy (twenty.iv weeks, eighteen.one–25.0) and only 145 women (3%) had their kickoff ultrasound examination in late pregnancy (30.ii weeks, 25.one–39.two). Crown–rump length was used for pregnancy dating until a GA of 12 weeks and v days (crown–rump length <65 mm), and biparietal diameter was used for pregnancy dating thereafter (GA from 12 weeks and v days onwards, biparietal diameter >23 mm). Methods for establishing GA and standard ultrasound planes for fetal measurements have been described previously. 14 Inter- and intra-observer intra-class correlation coefficients were all >0.98. 14

Preterm nativity was defined equally nativity earlier 37 weeks gestation (N = 226) and mail service-term nascency was defined as nativity after ≥42 weeks gestation (Northward = 382). As an boosted comparison group, we defined a group of children born before 35 weeks of gestation (Due north = 78) which is normally included in cohorts of preterm babies.

The Child Behavior Checklist for toddlers (CBCL/1.5–five) was used to obtain standardized parental reports of children'south behavioural and emotional bug. 15 , 16 The CBCL was a postal questionnaire and sent to exist filled out by the mother when the child was 18 months one-time and again when the child was 36 months old. At 36 months of age, nosotros too asked the father to make full out the CBCL. Each item (99 items in total) is scored on a 3-bespeak scale (0 = not true, 1 = somewhat or sometimes true and 2 = very truthful or often true), based on the child'south behaviour during the preceding 2 months. The sum of all problem items is the Full Bug score. At that place are five Diagnostic and Statistical Transmission of Mental Disorders (DSM)-oriented scales: feet problems, melancholia issues, pervasive developmental problems, ADHD and oppositional defiant problems. It has been shown that these DSM-oriented scales provide accurate and supplementary information on clinical diagnoses. 17 Also, good reliability and validity take been reported for the CBCL. sixteen We used the clinical cut-off scores (91st percentile for the Total Issues score and 98th percentile for the syndrome scales) to allocate children as having behavioural problems in the clinical range. 17 When parents filled out the questionnaire, they were not aware of our inquiry question exploring the relation betwixt post-term nascence and behavioural bug, just parents by and large are aware of the GA of their child and the risks associated with preterm birth. The maternal CBCL Total Problems ratings at 18 months and 36 months were correlated (r = 0.58, P < 0.001). Maternal and paternal CBCL Total Bug ratings at 36 months were correlated (r = 0.56, P < 0.001).

Several covariates were considered in the analyses and were chosen based on the existing literature and effect approximate changes. Maternal weight and height were measured at intake. Nosotros used postal questionnaires to obtain data on mother's parity, ethnicity and family unit income. Maternal ethnicity was defined according to the classification of Statistics Netherlands. xviii Educational level was categorized into iii levels: main, secondary and higher education. 19 Information most maternal smoking and alcohol use was obtained past questionnaires in each trimester. Based on these questionnaires, maternal smoking or drinking were categorized into 'no', 'until pregnancy was known' and 'connected during pregnancy' every bit described previously. 20 The Brief Symptom Inventory (BSI) was used to assess maternal psychopathology in mid-pregnancy; the BSI is a validated self-study questionnaire, which defines a spectrum of psychiatric symptoms. 21 Registries provided information on obstetric variables such as induction, birthweight, mode of commitment, umbilical artery pH and Apgar scores after 1 and five min. The post-natal questionnaire administered at age six and 12 months was used to gather information on breastfeeding and frequency of day intendance use.

For descriptive analyses, children were categorized in three groups based on GA: (i) born after 37 weeks of gestation up to and including 41 weeks and half-dozen days (term, reference group); (ii) born afterward <37 weeks of gestation (preterm); and (three) built-in after 42 + 0 weeks of gestation or more than (mail service-term). Chi-square and t-tests were used to compare maternal and kid characteristics. To test the associations betwixt GA and behavioural problems, nosotros used linear regression models with GA equally a continuous variable. We used the generalized estimating equation (GEE) to analyse the relation of GA with the behavioural and emotional outcomes measured at different time points. GEE adjusts for auto-correlation inside the aforementioned field of study. We used an unstructured correlation matrix, and thus no assumptions were made most the correlations. The GEE process provides a more precise result judge and reduces the fault derived from multiple comparisons (Type I error). A quadratic term was added to the linear regression models to test whether the associations between GA and behavioural problems were curvilinear. We conducted the primary analyses in all children, thus also including the children whose GA was assessed in the second and third trimester. This was done to reduce the risk of potential selection bias. Furthermore, we reran the analyses including only those children with a GA dating in early pregnancy (N = 4132), because GA dating by ultrasound is assumed to be more than accurate in early pregnancy. five

Moreover, we performed linear regression analyses for maternal ratings at eighteen and 36 months separately to assess whether the quadratic clan between GA at birth and child total problems was present at both ages. Nosotros likewise performed the same linear regression analyses for paternal ratings at 36 months. The results of these analyses can exist found in the Supplementary data, available at IJE online.

Both linear and quadratic analyses were rerun after exclusion of the preterm children, to define that the relationship betwixt GA and behavioural problems was not solely driven past the preterm children. In add-on, we restricted the analyses to the children born after 39 weeks of gestation. To bank check whether results were not unduly influenced by ethnicity, we reran analyses regarding the Full Problems score including only the indigenous Dutch children. Gender-specific estimates for the quadratic clan betwixt GA at birth and kid behavioural problems are provided in the Supplementary Table S1, available as Supplementary information at IJE online.

For logistic regression analyses, scales were dichotomized using the clinical cut-offs. We further explored the nature of the association between GA and behavioural problems with the GEE arroyo, and calculated the odds ratios (ORs) of clinical problem behaviour for pre- and post-term born children. We analysed only those scales on which >0.5% of the participants were classified equally having clinical problems; these were the ADHD, affective problems and pervasive developmental problems scales.

Potential confounders were chosen based on the literature and result guess changes. Both linear and logistic regression models were adjusted for child gender, maternal historic period, teaching, ethnicity, psychopathology, smoking and drinking during pregnancy, family income and age of the child at the time of assessments of the CBCL. Maternal weight, elevation, parity, breastfeeding and day care did non change the effect estimates (<5%). Maternal age, psychopathology and age of the child were used as continuous variables. Maternal education, ethnicity, smoking, drinking and family unit income were used as chiselled variables in the analyses.

Several post-hoc analyses were performed, including only mail-term children without induction, without assisted extraction or no high birthweight (>4000 g) to exam if effects were driven by these nativity characteristics.

Not all variables were available for each participant, the mean proportion of missing values was v.i% and these were imputed. Variables were centred and missing information were imputed with the mean or, for chiselled variables, dummy variables were made. The association between GA at nascence and child behaviour issues of the imputed and non-imputed information set were compared, and these associations were similar. Therefore, we simply report results of analyses with the imputed information.

For the non-response analysis, we compared maternal and child characteristics of included participants with participants from whom nosotros did not obtain behavioural data. Non-responders were lower educated (14.vii% principal education vs half dozen.3%, P < 0.001), younger (maternal historic period 28.1 vs 31.2 years, P < 0.001), more likely to exist non-Dutch (62.0 vs 35.4%, P < 0.001). Excluded infants had a lower birthweight (3313 vs 3431 1000, P < 0.001) and were born after a shorter period of gestation (39.v vs 39.8 weeks, P < 0.001), compared with included infants. The proportion of children born post-term was lower in the not-response group than in the response group (5.8 vs vi.9%, P < 0.001).

Results

Table one compares demographic and birth characteristics of 5145 children of whom 4537 (88.ii%) were born at term, 382 were born post-term (7.4%) and 226 were born preterm (4.4%).

Table 1

Maternal and child characteristics in the study population

Term a N = 4537 Post-term a North = 382
 Preterm a Due north = 226
Mean (SD) or % Hateful (SD) or % P (to ref) Mean (SD) or % P (to ref)
Maternal characteristics
    Age, mean years (SD) 31 (5) 31 (5) 0.34 31 (5) 0.55
    Education level, %
        Primary education six.9 5.8 0.46 7.1 0.89
        Secondary education 37.eight 31.4 0.01 39.8 0.57
        Higher education 52.0 59.2 <0.01 47.three 0.20
    Ethnicity, %
        Dutch 59.three 63.4 0.13 52.vii 0.05
        Other Western viii.six 10.5 0.22 8.0 0.90
        Turkish, Moroccan 11.i 11.5 0.80 10.6 0.91
        Surinamese, Antillean eight.ane 5.9 <0.01 x.6 0.17
    Psychopathology, mean score (SD) 0.25 (0.3) 0.23 (0.3) 0.43 0.28 (0.iv) 0.15
    Marital status, % single 9.4 7.8 0.35 14.eight 0.01
    Parity >1, % 12.two 10.2 0.15 8.four 0.09
Family income, %
        <€1200 eleven.v 10.5 0.62 18.i <0.01
        >€1200 and <€2000 xiv.seven 12.0 0.17 fourteen.6 1.00
        >€2000 63.four 67.v 0.11 53.5 <0.01
    Smoking throughout pregnancy % 14.vi 14.4 1.0 18.half dozen 0.xv
    Alcohol use throughout pregnancy, % 46.8 52.9 0.03 44.9 0.62
    Breastfeeding at ii months, % 68.8 71.5 0.31 63.5 0.12
Child characteristics
    GA, mean weeks (SD) 40.0 (i.1) 42.3 (0.3) <0.001 35.0 (2.0) <0.001
        Range 37.0–41.nine 42.0–43.four 26.7–36.9
    Birthweight, mean grams (SD) 3481 (486) 3819 (456) <0.001 2403 (604) <0.001
    Boys, % 49.ane 58.4 <0.001 46.0 0.15
    Suspected fetal distress, % 6.nine fifteen.ii <0.001 13.v <0.001
    Infirmary delivery, % 79.1 89.v <0.001 96.4 <0.001
    Labour induction, % 9.7 37.1 <0.001 12.9 0.16
    Meconium in amniotic fluid, % 15.viii 18.0 0.15 0.nine <0.001
    Assisted commitment, % viii.6 30.half dozen <0.001 xiii.4 0.033
    Caesarean commitment, % 11.6 eighteen.two <0.001 25.3 <0.001
    Apgar 5 min <7, % 1.0 0.viii 0.51 0.9 i.00
    pH umbilical artery <7.ane, % 3.8 3.3 0.45 2.9 0.68
    Behavioural scores measured with CBCL b
        Total problems
            Score at 18 months 23.53 (xv.66) 24.47 (16.71) 0.29 28.35 (17.73) <0.001
            Score at 36 months xx.52 (15.07) 22.29 (15.02) 0.04 24.ten (17.34) 0.002
    ADHD
        Mean score (SD) at 18 months iii.86 (two.45) 4.00 (2.45) 0.33 4.51 (2.56) <0.001
        Mean score (SD) at 36 months 2.95 (two.32) 3.08 (ii.31) 0.36 iii.43 (2.63) 0.007
    Affective problems
        Hateful score (SD) at 18 months 1.56 (i.69) 1.73 (i.ninety) 0.12 ii.09 (1.91) <0.001
        Mean score (SD) at 36 months 1.41 (1.58) 1.55 (ane.62) 0.12 1.78 (1.76) 0.002
    Pervasive developmental issues
        Mean score (SD) at 18 months one.73 (2.05) 1.86 (2.15) 0.28 2.27 (2.67) <0.001
        Mean score (SD) at 36 months i.99 (ii.26) 2.23 (2.32) 0.06 2.46 (2.87) 0.006
Term a Northward = 4537 Post-term a N = 382
 Preterm a N = 226
Mean (SD) or % Hateful (SD) or % P (to ref) Hateful (SD) or % P (to ref)
Maternal characteristics
    Age, hateful years (SD) 31 (v) 31 (v) 0.34 31 (5) 0.55
    Education level, %
        Master educational activity 6.9 5.8 0.46 vii.1 0.89
        Secondary education 37.8 31.4 0.01 39.8 0.57
        Higher education 52.0 59.2 <0.01 47.3 0.20
    Ethnicity, %
        Dutch 59.3 63.four 0.thirteen 52.7 0.05
        Other Western viii.6 10.5 0.22 8.0 0.ninety
        Turkish, Moroccan 11.1 xi.v 0.80 10.6 0.91
        Surinamese, Antillean 8.1 5.ix <0.01 10.6 0.17
    Psychopathology, mean score (SD) 0.25 (0.3) 0.23 (0.3) 0.43 0.28 (0.4) 0.fifteen
    Marital status, % single 9.4 seven.8 0.35 xiv.viii 0.01
    Parity >1, % 12.2 x.two 0.15 viii.4 0.09
Family income, %
        <€1200 eleven.v 10.5 0.62 18.1 <0.01
        >€1200 and <€2000 14.seven 12.0 0.17 14.six 1.00
        >€2000 63.iv 67.5 0.11 53.5 <0.01
    Smoking throughout pregnancy % 14.6 xiv.4 1.0 xviii.vi 0.fifteen
    Alcohol use throughout pregnancy, % 46.viii 52.9 0.03 44.9 0.62
    Breastfeeding at 2 months, % 68.8 71.5 0.31 63.5 0.12
Child characteristics
    GA, hateful weeks (SD) 40.0 (1.i) 42.iii (0.3) <0.001 35.0 (2.0) <0.001
        Range 37.0–41.9 42.0–43.4 26.7–36.9
    Birthweight, mean grams (SD) 3481 (486) 3819 (456) <0.001 2403 (604) <0.001
    Boys, % 49.1 58.4 <0.001 46.0 0.xv
    Suspected fetal distress, % 6.9 xv.two <0.001 13.5 <0.001
    Hospital delivery, % 79.i 89.5 <0.001 96.4 <0.001
    Labour induction, % 9.7 37.i <0.001 12.ix 0.sixteen
    Meconium in amniotic fluid, % 15.8 18.0 0.xv 0.9 <0.001
    Assisted delivery, % eight.6 xxx.6 <0.001 thirteen.4 0.033
    Caesarean delivery, % 11.6 18.2 <0.001 25.three <0.001
    Apgar v min <vii, % 1.0 0.eight 0.51 0.9 i.00
    pH umbilical artery <7.1, % iii.8 3.3 0.45 2.ix 0.68
    Behavioural scores measured with CBCL b
        Full problems
            Score at eighteen months 23.53 (15.66) 24.47 (sixteen.71) 0.29 28.35 (17.73) <0.001
            Score at 36 months twenty.52 (15.07) 22.29 (fifteen.02) 0.04 24.x (17.34) 0.002
    ADHD
        Mean score (SD) at xviii months three.86 (2.45) 4.00 (2.45) 0.33 4.51 (2.56) <0.001
        Mean score (SD) at 36 months 2.95 (2.32) 3.08 (ii.31) 0.36 3.43 (2.63) 0.007
    Affective problems
        Hateful score (SD) at 18 months i.56 (1.69) 1.73 (1.xc) 0.12 2.09 (1.91) <0.001
        Mean score (SD) at 36 months one.41 (i.58) one.55 (1.62) 0.12 ane.78 (one.76) 0.002
    Pervasive developmental problems
        Mean score (SD) at 18 months ane.73 (2.05) 1.86 (2.15) 0.28 2.27 (2.67) <0.001
        Mean score (SD) at 36 months ane.99 (2.26) 2.23 (2.32) 0.06 2.46 (two.87) 0.006

P-values are derived from t-tests for continuous variables and chi-foursquare tests for chiselled variables.

aCategorization was based on GA at nativity, term (GA from 37 weeks up to 42 weeks), preterm (GA <37 weeks) and post-term (GA of 42 weeks or more than).

bBehavioural and emotional trouble scores were measured using the CBCL reported past mother at 18 and 36 months.

Tabular array ane

Maternal and child characteristics in the study population

Term a N = 4537 Post-term a Northward = 382
 Preterm a Due north = 226
Mean (SD) or % Hateful (SD) or % P (to ref) Hateful (SD) or % P (to ref)
Maternal characteristics
    Age, mean years (SD) 31 (v) 31 (5) 0.34 31 (5) 0.55
    Teaching level, %
        Primary educational activity vi.9 five.8 0.46 7.1 0.89
        Secondary teaching 37.viii 31.4 0.01 39.8 0.57
        Higher education 52.0 59.two <0.01 47.3 0.20
    Ethnicity, %
        Dutch 59.3 63.iv 0.xiii 52.vii 0.05
        Other Western eight.6 10.5 0.22 8.0 0.90
        Turkish, Moroccan 11.1 eleven.5 0.fourscore 10.6 0.91
        Surinamese, Antillean eight.i 5.9 <0.01 10.6 0.17
    Psychopathology, hateful score (SD) 0.25 (0.3) 0.23 (0.three) 0.43 0.28 (0.4) 0.15
    Marital status, % single ix.4 vii.8 0.35 14.8 0.01
    Parity >1, % 12.two 10.2 0.fifteen viii.4 0.09
Family unit income, %
        <€1200 11.5 x.5 0.62 18.1 <0.01
        >€1200 and <€2000 xiv.7 12.0 0.17 14.6 one.00
        >€2000 63.4 67.five 0.11 53.five <0.01
    Smoking throughout pregnancy % 14.6 fourteen.iv 1.0 18.6 0.15
    Booze utilise throughout pregnancy, % 46.8 52.9 0.03 44.9 0.62
    Breastfeeding at 2 months, % 68.viii 71.five 0.31 63.5 0.12
Child characteristics
    GA, mean weeks (SD) 40.0 (i.1) 42.iii (0.3) <0.001 35.0 (2.0) <0.001
        Range 37.0–41.9 42.0–43.four 26.7–36.9
    Birthweight, mean grams (SD) 3481 (486) 3819 (456) <0.001 2403 (604) <0.001
    Boys, % 49.1 58.four <0.001 46.0 0.15
    Suspected fetal distress, % six.9 xv.2 <0.001 13.five <0.001
    Hospital delivery, % 79.1 89.5 <0.001 96.four <0.001
    Labour consecration, % nine.vii 37.ane <0.001 12.9 0.16
    Meconium in amniotic fluid, % 15.8 18.0 0.fifteen 0.nine <0.001
    Assisted delivery, % 8.6 xxx.vi <0.001 13.iv 0.033
    Caesarean delivery, % xi.half dozen 18.2 <0.001 25.iii <0.001
    Apgar 5 min <seven, % i.0 0.eight 0.51 0.nine 1.00
    pH umbilical artery <7.1, % 3.8 3.iii 0.45 two.9 0.68
    Behavioural scores measured with CBCL b
        Total issues
            Score at 18 months 23.53 (15.66) 24.47 (sixteen.71) 0.29 28.35 (17.73) <0.001
            Score at 36 months 20.52 (15.07) 22.29 (15.02) 0.04 24.ten (17.34) 0.002
    ADHD
        Mean score (SD) at 18 months 3.86 (two.45) 4.00 (2.45) 0.33 4.51 (2.56) <0.001
        Hateful score (SD) at 36 months 2.95 (2.32) 3.08 (two.31) 0.36 3.43 (2.63) 0.007
    Affective bug
        Mean score (SD) at 18 months 1.56 (1.69) 1.73 (one.90) 0.12 ii.09 (one.91) <0.001
        Mean score (SD) at 36 months i.41 (1.58) i.55 (1.62) 0.12 1.78 (1.76) 0.002
    Pervasive developmental bug
        Mean score (SD) at 18 months 1.73 (2.05) i.86 (2.15) 0.28 two.27 (2.67) <0.001
        Mean score (SD) at 36 months ane.99 (two.26) 2.23 (2.32) 0.06 two.46 (ii.87) 0.006
Term a N = 4537 Post-term a Due north = 382
 Preterm a N = 226
Hateful (SD) or % Hateful (SD) or % P (to ref) Hateful (SD) or % P (to ref)
Maternal characteristics
    Age, hateful years (SD) 31 (5) 31 (five) 0.34 31 (v) 0.55
    Education level, %
        Primary education 6.nine 5.8 0.46 7.ane 0.89
        Secondary education 37.eight 31.4 0.01 39.8 0.57
        Higher educational activity 52.0 59.two <0.01 47.3 0.20
    Ethnicity, %
        Dutch 59.3 63.four 0.13 52.7 0.05
        Other Western 8.vi 10.five 0.22 8.0 0.90
        Turkish, Moroccan 11.1 11.5 0.eighty 10.half dozen 0.91
        Surinamese, Antillean viii.i 5.nine <0.01 x.6 0.17
    Psychopathology, mean score (SD) 0.25 (0.3) 0.23 (0.3) 0.43 0.28 (0.4) 0.15
    Marital condition, % single 9.4 seven.viii 0.35 14.eight 0.01
    Parity >1, % 12.two 10.two 0.15 viii.iv 0.09
Family income, %
        <€1200 11.5 x.5 0.62 18.i <0.01
        >€1200 and <€2000 14.7 12.0 0.17 14.6 1.00
        >€2000 63.4 67.5 0.11 53.5 <0.01
    Smoking throughout pregnancy % xiv.6 fourteen.4 1.0 18.6 0.15
    Alcohol use throughout pregnancy, % 46.8 52.9 0.03 44.nine 0.62
    Breastfeeding at 2 months, % 68.8 71.5 0.31 63.5 0.12
Child characteristics
    GA, hateful weeks (SD) 40.0 (1.1) 42.3 (0.3) <0.001 35.0 (2.0) <0.001
        Range 37.0–41.ix 42.0–43.4 26.7–36.9
    Birthweight, mean grams (SD) 3481 (486) 3819 (456) <0.001 2403 (604) <0.001
    Boys, % 49.1 58.4 <0.001 46.0 0.15
    Suspected fetal distress, % 6.9 15.two <0.001 xiii.five <0.001
    Hospital delivery, % 79.one 89.5 <0.001 96.four <0.001
    Labour induction, % ix.seven 37.1 <0.001 12.9 0.16
    Meconium in amniotic fluid, % 15.8 18.0 0.15 0.nine <0.001
    Assisted delivery, % 8.6 30.half-dozen <0.001 13.4 0.033
    Caesarean delivery, % eleven.six 18.2 <0.001 25.3 <0.001
    Apgar 5 min <7, % 1.0 0.8 0.51 0.nine 1.00
    pH umbilical artery <7.1, % three.8 iii.3 0.45 2.nine 0.68
    Behavioural scores measured with CBCL b
        Total problems
            Score at 18 months 23.53 (xv.66) 24.47 (xvi.71) 0.29 28.35 (17.73) <0.001
            Score at 36 months 20.52 (15.07) 22.29 (xv.02) 0.04 24.10 (17.34) 0.002
    ADHD
        Hateful score (SD) at 18 months 3.86 (two.45) 4.00 (2.45) 0.33 4.51 (2.56) <0.001
        Hateful score (SD) at 36 months 2.95 (two.32) 3.08 (two.31) 0.36 iii.43 (2.63) 0.007
    Melancholia bug
        Mean score (SD) at 18 months 1.56 (i.69) 1.73 (1.ninety) 0.12 2.09 (1.91) <0.001
        Mean score (SD) at 36 months 1.41 (1.58) 1.55 (1.62) 0.12 1.78 (i.76) 0.002
    Pervasive developmental problems
        Hateful score (SD) at 18 months 1.73 (2.05) 1.86 (2.xv) 0.28 2.27 (ii.67) <0.001
        Hateful score (SD) at 36 months 1.99 (ii.26) 2.23 (2.32) 0.06 2.46 (two.87) 0.006

P-values are derived from t-tests for continuous variables and chi-square tests for chiselled variables.

aCategorization was based on GA at birth, term (GA from 37 weeks up to 42 weeks), preterm (GA <37 weeks) and post-term (GA of 42 weeks or more).

bBehavioural and emotional problem scores were measured using the CBCL reported by mother at 18 and 36 months.

In Figure 1, the unadjusted associations betwixt the Total Problems scale and GA at age xviii and 36 months are shown. The curves bear witness a nadir of the Total Bug score in children born with a GA effectually 40 weeks, whereas the mean trouble scores are higher in children who are born more preterm or more than post-term. In improver, we present a scatterplot of the correlation between GA at nativity and Total Bug score in the Supplementary information, bachelor at IJE online.

Figure 1

The unadjusted association between GA at birth and total behavioural and emotional problem score

The unadjusted association between GA at birth and total behavioural and emotional problem score

Figure one

The unadjusted association between GA at birth and total behavioural and emotional problem score

The unadjusted clan betwixt GA at birth and total behavioural and emotional problem score

For continuous scores on the total problems, ADHD, melancholia problems scales and pervasive developmental problems, linear regression analyses showed a curvilinear relation betwixt GA and behavioural problems, indicating that children with shorter or longer gestation had college behavioural problem scores compared with children born at term (Table 2). After exclusion of the preterm born children, the curvilinear relations between GA and behavioural bug remained, showing that mean trouble scores were college in children with a longer GA [Total Problems score β GAii = 0.34, 95% confidence interval (CI) = 0.fourteen–0.54]. When we restricted the analyses to the children born afterward 39 weeks of gestation (north = 4115), we still observed a linear association between GA at birth and total child behavioural and emotional problems (data not shown).

Tabular array ii

Association between GA at birth and behavioural and emotional problem score (continuous)

Total problems ADHD Affective problems Pervasive developmental problems
β (95% CI) β (95% CI) β (95% CI) β (95% CI)
Model I
    Linear model; GA −0.24 (−0.48 to 0.01) −0.04 (−0.08 to 0.01) −0.04 (−0.06 to 0.10) −0.05 (−0.09 to −0.02)
    Quadratic model; GA 0.05 (−0.21 to 0.32) −0.01 (−0.05 to 0.04) 0.00 (−0.03 to 0.06) −0.03 (−0.06 to 0.01)
    GA2 0.13 (0.06 to 0.20) 0.01 (0.00 to 0.03) 0.02 (0.01 to 0.02) 0.01 (0.00 to 0.03)
Model II
    Linear model; GA 0.15 (−0.16 to 0.46) 0.01 (−0.05 to 0.06) 0.08 (−0.03 to 0.04) −0.02 (−0.06 to 0.02)
    Quadratic model; GA −0.06 (−0.39 to 0.28) 0.02 (−0.08 to 0.03) −0.01 (−0.05 to 0.02) −0.05 (−0.09 to −0.01)
    GA2 0.34 (0.14 to 0.54) 0.05 (0.02 to 0.08) 0.03 (0.01 to 0.05) 0.04 (0.02 to 0.07)
Total problems ADHD Melancholia problems Pervasive developmental issues
β (95% CI) β (95% CI) β (95% CI) β (95% CI)
Model I
    Linear model; GA −0.24 (−0.48 to 0.01) −0.04 (−0.08 to 0.01) −0.04 (−0.06 to 0.10) −0.05 (−0.09 to −0.02)
    Quadratic model; GA 0.05 (−0.21 to 0.32) −0.01 (−0.05 to 0.04) 0.00 (−0.03 to 0.06) −0.03 (−0.06 to 0.01)
    GAtwo 0.13 (0.06 to 0.20) 0.01 (0.00 to 0.03) 0.02 (0.01 to 0.02) 0.01 (0.00 to 0.03)
Model Ii
    Linear model; GA 0.15 (−0.16 to 0.46) 0.01 (−0.05 to 0.06) 0.08 (−0.03 to 0.04) −0.02 (−0.06 to 0.02)
    Quadratic model; GA −0.06 (−0.39 to 0.28) 0.02 (−0.08 to 0.03) −0.01 (−0.05 to 0.02) −0.05 (−0.09 to −0.01)
    GA2 0.34 (0.14 to 0.54) 0.05 (0.02 to 0.08) 0.03 (0.01 to 0.05) 0.04 (0.02 to 0.07)

Behavioural and emotional problem scores were measured using the CBCL reported by female parent at 18 and 36 months.

Model I: included all children.

Model II: included all children born after 37 weeks.

All models were adjusted for maternal age, education, ethnicity, psychopathology, smoking and drinking during pregnancy, family income, gender of the kid and age of the child at the assessment of the CBCL.

β gives the estimate of increment in CBCL score per week increase of the centred GA. Bold values correspond findings that were considered statistically significant (P<0.05).

Table two

Association between GA at nascency and behavioural and emotional problem score (continuous)

Total problems ADHD Melancholia problems Pervasive developmental issues
β (95% CI) β (95% CI) β (95% CI) β (95% CI)
Model I
    Linear model; GA −0.24 (−0.48 to 0.01) −0.04 (−0.08 to 0.01) −0.04 (−0.06 to 0.10) −0.05 (−0.09 to −0.02)
    Quadratic model; GA 0.05 (−0.21 to 0.32) −0.01 (−0.05 to 0.04) 0.00 (−0.03 to 0.06) −0.03 (−0.06 to 0.01)
    GA2 0.13 (0.06 to 0.xx) 0.01 (0.00 to 0.03) 0.02 (0.01 to 0.02) 0.01 (0.00 to 0.03)
Model Two
    Linear model; GA 0.15 (−0.16 to 0.46) 0.01 (−0.05 to 0.06) 0.08 (−0.03 to 0.04) −0.02 (−0.06 to 0.02)
    Quadratic model; GA −0.06 (−0.39 to 0.28) 0.02 (−0.08 to 0.03) −0.01 (−0.05 to 0.02) −0.05 (−0.09 to −0.01)
    GA2 0.34 (0.14 to 0.54) 0.05 (0.02 to 0.08) 0.03 (0.01 to 0.05) 0.04 (0.02 to 0.07)
Total problems ADHD Affective problems Pervasive developmental problems
β (95% CI) β (95% CI) β (95% CI) β (95% CI)
Model I
    Linear model; GA −0.24 (−0.48 to 0.01) −0.04 (−0.08 to 0.01) −0.04 (−0.06 to 0.10) −0.05 (−0.09 to −0.02)
    Quadratic model; GA 0.05 (−0.21 to 0.32) −0.01 (−0.05 to 0.04) 0.00 (−0.03 to 0.06) −0.03 (−0.06 to 0.01)
    GA2 0.13 (0.06 to 0.20) 0.01 (0.00 to 0.03) 0.02 (0.01 to 0.02) 0.01 (0.00 to 0.03)
Model Ii
    Linear model; GA 0.15 (−0.16 to 0.46) 0.01 (−0.05 to 0.06) 0.08 (−0.03 to 0.04) −0.02 (−0.06 to 0.02)
    Quadratic model; GA −0.06 (−0.39 to 0.28) 0.02 (−0.08 to 0.03) −0.01 (−0.05 to 0.02) −0.05 (−0.09 to −0.01)
    GAtwo 0.34 (0.14 to 0.54) 0.05 (0.02 to 0.08) 0.03 (0.01 to 0.05) 0.04 (0.02 to 0.07)

Behavioural and emotional trouble scores were measured using the CBCL reported by mother at 18 and 36 months.

Model I: included all children.

Model II: included all children born after 37 weeks.

All models were adapted for maternal age, instruction, ethnicity, psychopathology, smoking and drinking during pregnancy, family unit income, gender of the child and age of the child at the assessment of the CBCL.

β gives the gauge of increase in CBCL score per week increase of the centred GA. Bold values stand for findings that were considered statistically significant (P<0.05).

Supplementary analyses demonstrated that results were similar when children with second or tertiary trimester GA dating were excluded (Full Issues score β GA2 = 0.12, 95% CI = 0.06–0.18). Moreover, analyses on the Total Issues score were rerun in a smaller subset of Dutch children; the results were somewhat similar (β GA2 = 0.08, 95% CI = 0.01–0.12). In addition, there was no interaction betwixt GA and the ii time points of CBCL measurement indicating that effects remained stable over early childhood (data non shown).

Dissever linear regression analyses using the two maternal ratings each demonstrated that the quadratic clan between GA at nascency and kid behavioural issues was present at 18 and 36 months ( Supplementary Table S2, available as Supplementary data at IJE online). Analyses using the paternal ratings of kid behavioural and emotional problems also demonstrated a quadratic relationship between GA at birth and kid emotional and behavioural outcomes ( Supplementary Table S3, available equally Supplementary information at IJE online).

Table three shows that post-term children were almost twice equally likely as term born children to take clinical problem behaviour on the Total Bug scale and were more likely to have problems in the clinical range on the ADHD scale. Compared with term born children, post-term children did not have higher ORs on the affective bug or pervasive developmental bug scales.

Table 3

Association between GA at nascence and behavioural and emotional problems (clinical cutting-off)

Total problems ADHD Affective problems Pervasive developmental problems
OR (95% CI) OR (95% CI) OR (95% CI) OR (95% CI)
Term nascency N = 4537 1.0 1.0 1.0 1.0
Post-term birth N = 382 1.83 (1.17–2.85) ii.04 (i.18–3.55) i.48 (0.88–two.51) ane.84 (0.95–3.55)
Preterm nascence <37 weeks N = 226 2.35 (ane.43–3.88) 2.28 (one.21–4.28) ane.51 (0.83–2.76) 1.83 (0.84–3.97)
Preterm birth <35 weeks N = 78 3.00 (1.48–6.09) 3.42 (1.41–8.32) i.92 (0.74–four.99) three.95 (1.47–10.6)
Total problems ADHD Affective bug Pervasive developmental issues
OR (95% CI) OR (95% CI) OR (95% CI) OR (95% CI)
Term birth N = 4537 ane.0 1.0 1.0 1.0
Mail service-term nativity N = 382 1.83 (1.17–two.85) ii.04 (1.xviii–3.55) 1.48 (0.88–two.51) one.84 (0.95–3.55)
Preterm birth <37 weeks N = 226 two.35 (1.43–3.88) 2.28 (1.21–4.28) 1.51 (0.83–2.76) 1.83 (0.84–three.97)
Preterm birth <35 weeks Due north = 78 3.00 (1.48–half-dozen.09) 3.42 (1.41–8.32) 1.92 (0.74–four.99) 3.95 (1.47–10.6)
Prevalence of behavioural and emotional problems
Total bug (%) ADHD (%) Affective problems (%) Pervasive developmental problems (%)
Bug at 18 months iv.2 2.5 3.5 i.eight
Problems at 36 months iii.1 1.2 two.v ii.0
Prevalence of behavioural and emotional problems
Total issues (%) ADHD (%) Melancholia issues (%) Pervasive developmental issues (%)
Bug at 18 months 4.2 2.v 3.v 1.8
Problems at 36 months 3.1 one.2 two.5 2.0

Behavioural and emotional problem scores were measured using the CBCL reported by mother at eighteen and 36 months.

All models were adjusted for maternal age, education, ethnicity, psychopathology, smoking and drinking during pregnancy, family income, gender of the child and age of the kid at the assessment of the CBCL.

Categorization was based on GA at birth, term (GA from 37 weeks up to 42 weeks), post-term (GA of 42 weeks or more) and preterm (GA <37 weeks or <35 weeks). Bold values correspond findings that were considered statistically pregnant (P<0.05).

Tabular array 3

Association between GA at nascence and behavioural and emotional problems (clinical cutting-off)

Total problems ADHD Affective problems Pervasive developmental problems
OR (95% CI) OR (95% CI) OR (95% CI) OR (95% CI)
Term birth N = 4537 1.0 1.0 1.0 1.0
Post-term birth N = 382 ane.83 (1.17–two.85) ii.04 (1.18–three.55) ane.48 (0.88–2.51) 1.84 (0.95–iii.55)
Preterm birth <37 weeks Northward = 226 2.35 (1.43–3.88) 2.28 (one.21–4.28) 1.51 (0.83–two.76) i.83 (0.84–3.97)
Preterm birth <35 weeks N = 78 three.00 (1.48–half dozen.09) 3.42 (one.41–eight.32) 1.92 (0.74–4.99) 3.95 (one.47–x.6)
Total problems ADHD Melancholia bug Pervasive developmental bug
OR (95% CI) OR (95% CI) OR (95% CI) OR (95% CI)
Term nativity Due north = 4537 1.0 1.0 1.0 1.0
Post-term nativity Northward = 382 ane.83 (one.17–2.85) 2.04 (1.18–3.55) 1.48 (0.88–2.51) ane.84 (0.95–3.55)
Preterm birth <37 weeks N = 226 2.35 (1.43–3.88) 2.28 (1.21–iv.28) 1.51 (0.83–2.76) 1.83 (0.84–3.97)
Preterm birth <35 weeks N = 78 iii.00 (1.48–half-dozen.09) three.42 (i.41–eight.32) 1.92 (0.74–4.99) 3.95 (i.47–x.half dozen)
Prevalence of behavioural and emotional problems
Total problems (%) ADHD (%) Affective problems (%) Pervasive developmental problems (%)
Problems at 18 months four.2 2.5 3.5 i.8
Issues at 36 months three.1 1.two two.5 2.0
Prevalence of behavioural and emotional problems
Total problems (%) ADHD (%) Affective problems (%) Pervasive developmental problems (%)
Problems at 18 months 4.2 2.5 3.5 1.8
Problems at 36 months 3.one 1.2 2.5 2.0

Behavioural and emotional problem scores were measured using the CBCL reported by mother at 18 and 36 months.

All models were adapted for maternal historic period, education, ethnicity, psychopathology, smoking and drinking during pregnancy, family income, gender of the kid and age of the child at the assessment of the CBCL.

Categorization was based on GA at birth, term (GA from 37 weeks up to 42 weeks), mail service-term (GA of 42 weeks or more) and preterm (GA <37 weeks or <35 weeks). Bold values represent findings that were considered statistically significant (P<0.05).

The preterm group showed considerably more behavioural or emotional bug compared with the term group; this group was more likely to develop problems on the Total Problems scale and the ADHD scale. With a more than stringent cut-off for preterm birth (<35 weeks), we constitute that these children were more than likely to have problems in the clinical range on the Total Problems calibration, ADHD scale and the pervasive developmental problems calibration.

In add-on, some groups of children were excluded from the analyses. These exclusions did not change the results. The hazard for developing total problems in children born post-term remained nowadays after excluding children with consecration (OR = one.77, 95% CI = one.01–3.10) or after excluding children >4000 g of nascence weight (OR = one.83, 95% CI = 1.06–3.15).

Word

Our study demonstrated that children born post-term were more likely than their term built-in peers to have emotional and behavioural problems at both xviii and 36 months later on birth.

Post-term delivery and behavioural bug could exist explained in several pathways. Showtime, a larger baby typically has a higher risk for perinatal issues. Prolonged labour, cephalopelvic disproportion and shoulder dystocia are increased in post-term children. 2 A perinatal lack of oxygen has been associated with behavioural problems. 22 However, our results did not suggest increased fetal stress in the post-term children, as indicated by low Apgar score, low umbilical pH or meconium-stained amniotic fluid. We controlled for several nascency characteristics. Moreover, exclusion of mail-term children with induction and >4000 g of nascence weight did not change results. A second caption is uteroplacental insufficiency: a non-optimal 'old' placenta offers fewer nutrients and less oxygen than a full term fetus requires. 1 The lack of nutrients and oxygen may predispose to abnormal fetal development and this may lead to abnormal emotional and behavioural evolution. 23 In our written report, we could not distinguish possible effects of uteroplacental insufficiency from perinatal problems. Thirdly, it is possible that a disturbance of the 'placental clock', which controls the length of pregnancy, is involved. A marker of this clock is the placental secretion of corticotrophin-releasing hormone (CRH), which is lower in women who deliver mail service-term than in women delivering at term. 24 CRH is the main regulator of the maternal and fetal hypothalamic–pituitary–adrenal (HPA) axis. 25 It has been suggested that placental endocrine malfunctioning or maternal stress at critical times during fetal development may influence the fetal HPA centrality, leading to neuroendocrine abnormalities that could increase the child's vulnerability to emotional and behavioural problems after in life. 26 Finally, the association between post-term nascency and childhood behavioural problems could be explained by underlying causes of beingness born post-term. In other words, the cause for mail-term could also be the cause for having behavioural issues, for instance neurodevelopmental factors related to behavioural issues could be involved in the circuitous process of nativity.

This is a population-based written report including many post-term children. We measured problem behaviour with the same validated musical instrument (CBCL/one.5–5) at two time points. As ultrasound gestational dating is thought to be superior to terminal menstrual period-based gestational dating, 5 we decided to use primarily ultrasound dating. Eighty percent of our sample was dated with ultrasound cess in early pregnancy. Nonetheless, some limitations must be discussed. Firstly, mothers were non formally blinded for the GA of their children and they might perceive more behavioural bug in post-term children. Even so, the notion that a mail service-term birth may betoken at-risk babies is largely non-existent in the medical profession and absent in the public debate. Secondly, in the current study, we relied on the CBCL, every bit it was not feasible to obtain clinical diagnoses in such a large number of children. Moreover, these children were too immature to be assessed by teachers or other informants, thus nosotros had to rely on parental ratings that may be biased. Moreover, the CBCL is not a clinical instrument and cannot provide diagnoses, but addresses continuous traits in children. However, the DSM-oriented scales provide accurate information 17 and good reliability and validity have been reported. 16

Finally, although we controlled for a large number of confounders, including maternal smoking, psychopathology and socio-economical characteristics, rest misreckoning, for instance maternal malnutrition during pregnancy, cannot be ruled out.

Management of prolonged pregnancy follows two approaches: proposing induction before 42 weeks of gestation or close monitoring of pregnancy later 41 weeks with selective induction in case of fetal distress or a favourable Bishop score. 4 Pregnancy and perinatal care are criticized in The Netherlands, as perinatal mortality ranks equally the third worst in Europe. 27 Until mid-2008, a woman with a depression-risk pregnancy at 42 weeks was referred to a gynaecologist for shut monitoring simply. The electric current revised policy requires a referral at 41 weeks. Although the charge per unit of post-term births went downwards afterwards introducing first trimester ultrasound dating of GA, 5 mail-term delivery remains common. 4

In determination, mail-term children take a considerably higher risk of clinically relevant problem behaviour. They are more than twice as likely as term born children to take clinical ADHD. Farther research is needed to determine the causes of post-term birth to reduce post-term nascence rates and to minimize long-term consequences. Besides, longer follow-up is necessary to establish whether the relationship between post-term nascency and behavioural bug will persist.

Funding

The Sophia Children'south Hospital Fund (projection number 553) and the WH Kröger Foundation. The first phase of the Generation R Written report is fabricated possible by financial support from the Erasmus Medical Centre, the Erasmus University and The Netherlands Arrangement for Health Inquiry and Development (Zon MW, grant ZonMW Geestkracht 10.000.1003).

Acknowledgments

The Generation R Report is conducted by the Erasmus Medical Centre in shut collaboration with the School of Law and Kinesthesia of Social Sciences of the Erasmus University Rotterdam, the Municipal Health Service Rotterdam area, the Rotterdam Homecare Foundation and the Stichting Trombosedienst & Artsenlaboratorium Rijnmond (STAR), Rotterdam. Nosotros gratefully admit the contribution of general practitioners, hospitals, midwives and pharmacies in Rotterdam. H.Due east.K. checked the references used in this article for accuracy and completeness. H.T. will act as guarantor for the commodity. Someone with an excellent mastery of the English language language has advisedly edited the article. This article represents original cloth and has non been published previously in whole or in part. In add-on, no similar paper is in printing or under review elsewhere.

Conflict of interest: F.C.Five. is writer and caput of the Department of Kid and Boyish Psychiatry at Erasmus MC, which publishes the Achenbach Arrangement of Empirically Based Assessment (ASEBA) and from which he receives remuneration. All other authors report no conflicts of interest.

  • GA at birth and behavioural and emotional issues in early childhood show a not-linear quadratic relation indicating that both preterm and post-term children are at higher hazard for problems.

  • Children born post-term were twice as likely as their term-born peers to have ADHD in early babyhood.

  • Our results propose that children built-in postal service-term take a neurodevelopmental delay. However, farther research is needed to demonstrate a causal relation.

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    • Supplementary information