Gestational age and socio-demographic factors associated with school performance at the age of 12 years, a population-based study.

BACKGROUND: Gestational age is positively associated with cognitive development, but socio-demographic factors also influence school performance. Previous studies suggested possible interaction, putting children with low socio-economic status (SES) at increased risk of the negative effects of prematurity. OBJECTIVES: To investigate the association between gestational age in weeks, socio-demographic characteristics, and school performance at the age of 12 years among children in regular primary education. METHODS: Population-based cohort study among liveborn singletons (N = 860,332) born in the Netherlands in 1999-2006 at 25-42 weeks' gestation, with school performance from 2011 to 2019. Regression analyses were conducted investigating the association of gestational age and sociodemographic factors with school performance and possible interaction. RESULTS: School performance increased with gestational age up to 40 weeks. This pattern was evident across socio-demographic strata. Children born at 25 weeks had -0.57 SD (95% confidence interval -0.79, -0.35) lower school performance z-scores and lower secondary school level compared to 40 weeks. Low maternal education, low maternal age, and non-European origin were strongly associated with lower school performance. Being born third or later and low socioeconomic status (SES) were also associated with lower school performance, but differences were smaller than among other factors. When born preterm, children from mothers with low education level, low or high age, low SES or children born third or later were at higher risk for lower school performance compared to children of mothers with intermediate education level, aged 25-29 years, with intermediate SES or first borns (evidence of interaction). CONCLUSIONS: Higher gestational age is associated with better school performance at the age of 12 years along the entire spectrum of gestational age, beyond the cut-off of preterm birth and across socio-demographic differences. Children in socially or economically disadvantaged situations might be more vulnerable to the negative impact of preterm birth. Other important factors in school performance are maternal education, maternal age, ethnicity, birth order and SES. Results should be interpreted with caution due to differential loss to follow-up.

Does induction of labor at 41 weeks (early, mid or late) improve birth outcomes in low-risk pregnancy? A nationwide propensity score-matched study.

INTRODUCTION: This study aimed to assess whether induction of labor at 41 weeks of gestation improved perinatal outcomes in a low-risk pregnancy compared with expectant management. MATERIAL AND METHODS: Registry-based national cohort study in The Netherlands. The study population comprised 239 971 low-risk singleton pregnancies from 2010 to 2019, with birth occurring from 41+0 to 42+0 weeks. We used propensity score matching to compare induction of labor in three 2-day groups to expectant management, and further conducted separate analyses by parity. The main outcome measures were stillbirth, perinatal mortality, 5-min Apgar <4 and <7, neonatal intensive care unit (NICU) admissions ≥24 h, and emergency cesarean section rate. RESULTS: Compared with expectant management, induction of labor at 41+0 to 41+1 weeks resulted in reduced stillbirths (adjusted odds ratio [aOR] 0.15, 95% confidence interval [CI] 0.05-0.51) in both nulliparous and multiparous women. Induction of labor increased 5-min Apgar score <7 (aOR 1.30, 95% CI 1.09-1.55) and NICU admissions ≥24 h (aOR 2.12, 95% CI 1.53-2.92), particularly in nulliparous women, and increased the cesarean section rate (aOR 1.42, 95% CI 1.34-1.51). At 41+2-41+3 weeks, induction of labor reduced perinatal mortality (aOR 0.13, 95% CI 0.04-0.43) in both nulliparous and multiparous women. The rate of 5-min Apgar score <7 was increased (aOR 1.26, 95% CI 1.06-1.50), reaching significance in multiparous women. The cesarean section rate increased (aOR 1.57, 95% CI 1.48-1.67) in both nulliparous and multiparous women. Induction of labor at 41+4 to 41+5 weeks reduced stillbirths (aOR 0.30, 95% CI 0.10-0.93). Induction of labor increased rates of 5-min Apgar score <4 (aOR 1.61, 95% CI 1.01-2.56) and NICU admissions ≥24 h (aOR 1.52, 95% CI 1.08-2.13) in nulliparous women. Cesarean section rate was increased (aOR 1.47, 95% CI 1.38-1.57) in nulliparous and multiparous women. CONCLUSIONS: At 41+2 to 41+3 weeks, induction of labor reduced perinatal mortality, and in all 2-day groups at 41 weeks, it reduced stillbirths, compared with expectant management. Low 5-min Apgar score (<7 and <4) and NICU admissions ≥24 h occurred more often with induction of labor, especially in nulliparous women. Induction of labor in all 2-day groups coincided with elevated cesarean section rates in nulliparous and multiparous women. These findings pertaining to the choice of induction of labor vs expectant management should be discussed when counseling women at 41 weeks of gestation.

Decreasing trend in preterm birth and perinatal mortality, do disparities also decline?

BACKGROUND: In the Netherlands, several initiatives started after the publication of the PERISTAT findings that showed the perinatal mortality risk was higher than in other European countries. The objective of this study is 1) to report recent trends in perinatal mortality and in intermediate risk groups (preterm birth, congenital anomalies and small for gestational age (SGA)), 2) describing perinatal mortality risk among children born preterm, with congenital anomalies or SGA, and born in maternal high risk groups (parity, age, ethnicity and socio-economic status (SES)). METHODS: A nationwide cohort study in the Netherlands among 996,423 singleton births in 2010-2015 with a gestational age between 24.0 and 42.6 weeks. Trend tests, univariate and multivariable logistic regression analyses were used. We did separate analyses for gestational age subgroups and line of care. RESULTS: The perinatal mortality rate was 5.0 per 1000 and it decreased significantly from 5.6 in 2010 to 4.6 per 1000 in 2015. Preterm birth significantly declined (6.1% in 2010 to 5.6% in 2015). Analysis by gestational age groups showed that the largest decline in perinatal mortality of 32% was seen at 24-27 weeks of gestation where the risk declined from 497 to 339 per 1000. At term, the decline was 23% from 2.2 to 1.7 per 1000. The smallest decline was 3% between 32 and 36 weeks. In children with preterm birth, congenital anomalies or SGA, the perinatal mortality risk significantly declined. Main risk factors for perinatal mortality were African ethnicity (adjusted odds ratio (aOR) 2.1 95%CI [1.9-2.4]), maternal age ≥ 40 years (aOR1.9 95%CI [1.7-2.2]) and parity 2+ (aOR 1.4 95%CI [1.3-1.5]). Among the (post)term born neonates, there was no significant decline in perinatal mortality in women with low age, low or high SES, non-Western ethnicity and among women who started or delivered under primary care. CONCLUSIONS: There is a decline in preterm birth and in perinatal mortality between 2010 and 2015. The decline in perinatal mortality is both in stillbirths and in neonatal mortality, most prominently among 24-27 weeks and among (post)term births. A possible future target could be deliveries among 32-36 weeks, women with high maternal age or non-Western ethnicity.

Intrapartum epidural analgesia and low Apgar score among singleton infants born at term: A propensity score matched study.

INTRODUCTION: The associations of epidural analgesia and low Apgar score found in the Swedish Registry might be a result of confounding by indication. The objective of this study was to assess the possible effect of intrapartum epidural analgesia on low Apgar score and neonatal intensive care unit (NICU) admission in term born singletons with propensity score matching. MATERIAL AND METHODS: This was a propensity score matched study (n = 257 872) conducted in a national cohort of 715 449 term live born singletons without congenital anomalies in the Netherlands. Mothers with prelabor cesarean section were excluded. Main outcome measures were 5-minute Apgar score <7, 5-minute Apgar score <4 and admission to a NICU for at least 24 hours. First, an analysis of the underlying risk factors for low Apgar score <7 was performed. Multivariable analyses were applied to assess the effect of the main risk factor, intrapartum epidural analgesia, on low Apgar score to adjust the results for confounding factors. Second, a propensity score matched analysis on the main risk factors for epidural analgesia was applied. By propensity score matching the (confounding) characteristics of the women who received epidural analgesia with the characteristics of the control women without epidural analgesia, the effect of possible confounding by indication is minimized. RESULTS: Intrapartum epidural analgesia was performed in 128 936 women (18%). Apgar score <7 was present in 1.0%, Apgar score <4 in .2% and NICU admission in .4% of the deliveries. The strongest risk factor for Apgar score <7 was epidural analgesia (adjusted odds ratio [aOR] 1.9, 95% confidence interval [CI] 1.8-2.0). The propensity score matched adjusted analysis of women with epidural analgesia showed significant adverse neonatal outcomes: aOR 1.8 (95% CI 1.7-1.9) for AS <7, aOR 1.6 (95% CI 1.4-1.9) for AS <4 and aOR 1.7 (95% CI 1.6-1.9) for NICU admission. The results of epidural analgesia on AS <7 were also significantly increased for spontaneous start of labor (aOR 2.0, 95% CI 1.8-2.1) and for spontaneous delivery. CONCLUSIONS: Intrapartum epidural analgesia at term is strongly associated with low Apgar score and more NICU admissions, especially in spontaneous deliveries. This association needs further research and awareness.

Intrapartum and neonatal mortality in low-risk term women in midwife-led care and obstetrician-led care at the onset of labor: A national matched cohort study.

INTRODUCTION: Midwife-led models of care have been the subject of debate for many years. We conducted a study to compare intrapartum and neonatal mortality rates in midwife-led (primary) vs obstetrician-led (secondary) care at the onset of labor in low-risk term women. MATERIAL AND METHODS: We performed an unmatched and a propensity score matched cohort study using data from the national perinatal audit registry (PAN) and from the national perinatal registry (PERINED) of the Netherlands. We included women with singleton pregnancies (without congenital anomalies or antepartum fetal death) who gave birth at term between 2010 and 2012. We excluded the following major risk factors: non-vertex position of the fetus, previous cesarean birth, hypertension, diabetes mellitus, prolonged rupture of membranes (≥24 hours), vaginal bleeding in the second half of pregnancy, nonspontaneous start of labor and post-term pregnancy (≥42 weeks). The primary outcome was intrapartum or neonatal mortality up to 28 days after birth. Secondary outcome measures were mode of delivery and a 5-minute Apgar score <7. RESULTS: We included 259 211 women. There were 100/206 642 (0.48‰) intrapartum and neonatal deaths in the midwife group and 23/52 569 (0.44‰) in the obstetrician group (odds ratio [OR] 1.11, 95% CI 0.70-1.74). Propensity score matched analysis showed mortality rates of 0.49‰ (26/52 569) among women in midwife-led care and 0.44‰ (23/52 569) for women in obstetrician-led care (OR 1.13, 95% CI 0.65-1.98). In the midwife group there were significantly lower rates of vaginal instrumental deliveries (8.4% vs 13.0%; matched OR 0.65, 95% CI 0.62-0.67) and intrapartum cesarean sections (2.6% vs 8.2%; matched OR 0.32, 95% CI 0.30-0.34), and fewer neonates with low Apgar scores (<7 after 5 minutes) (0.69% vs 1.11%; matched OR 0.61, 95% CI 0.53-0.69). CONCLUSIONS: Among low-risk term women, there were comparable intrapartum and neonatal mortality rates for women starting labor in midwife-led vs obstetrician-led care, with lower intervention rates and fewer low Apgar scores in the midwife group.

Small for gestational age and perinatal mortality at term: An audit in a Dutch national cohort study.

OBJECTIVE: To assess the underlying risk factors for perinatal mortality in term born small for gestational age infants. STUDY DESIGN: We performed a population based nationwide cohort study in the Netherlands of 465,532 term born infants from January 2010 to January 2013. Logistic regression analyses were performed. Also audit results were studied for detailed care information. RESULTS: We studied 162 small for gestational age infants who died in the perinatal period. Risk factors were: gestational age at 37completed weeks (adjusted Odds Ratio (aOR) 2.6, 95% Confidence Interval (CI) 1.6-4.3), male gender (aOR 1.4, 95% CI 1.01-1.9), South Asian ethnicity (aOR 3.6, 95% CI 1.6-8.4), African (aOR 3.5, 95% CI 1.9-6.5) and other non-Western ethnicity (aOR 1.9, CI 1.2-3.1). At 37 completed weeks gestation audit results showed that 26% of the women smoked, 91% were boys and in all but one case death occurred before birth. In 61% of all deceased SGA infants born at 37 completed weeks gestation referral from primary care by independent midwives to the obstetrician took place because of antepartum death before labor. CONCLUSIONS: Gestational age of 37 completed weeks, male gender, South Asian, African or other non-Western ethnicity and smoking are associated with perinatal mortality in SGA infants. These risk factors concern the complete term population starting at 37 weeks or even earlier. Therefore, it is of utmost importance to develop accurate diagnostic tests to screen for SGA before 36 weeks gestation to prevent perinatal mortality at term in SGA infants.

Antenatal prediction of neonatal mortality in very premature infants.

OBJECTIVE: To develop a prognostic model for antenatal prediction of neonatal mortality in infants threatening to be born very preterm (<32 weeks). STUDY DESIGN: Nationwide cohort study in The Netherlands between 1999 and 2007. We studied 8500 singletons born between 25(+0) and 31(+6) weeks of gestation where fetus was alive at birth without congenital anomalies. We developed a multiple logistic regression model to estimate the risk of neonatal mortality within 28 days after birth, based on characteristics that are known before birth. We used bootstrapping techniques for internal validation. Discrimination (AUC), accuracy (Brier score) and calibration (graph, c-statistics) were used to assess the model's predictive performance. RESULTS: Neonatal mortality occurred in 766 (90 per 1000) live births. The final model consisted of seven variables. Predictors were low gestational age, no antental corticosteroids, male gender, maternal age ≥35 years, Caucasian ethnicity, non-cephalic presentation and non-3rd level of hospital. The predicted probabilities ranged from 0.003 to 0.697 (IQR 0.02-0.11). The model had an AUC of 0.83, the Brier score was 0.065. The calibration graph showed good calibration, and the test for the Hosmer Lemeshow c-statistic showed no lack of fit (p=0.43). CONCLUSIONS: Neonatal mortality can be predicted for very preterm births based on the antenatal factors gestational age, antental corticosteroids, fetal gender, maternal age, ethnicity, presentation and level of hospital. This model can be helpful in antenatal counseling.

Term perinatal mortality audit in the Netherlands 2010-2012: a population-based cohort study.

OBJECTIVE: To assess the implementation and first results of a term perinatal internal audit by a standardised method. DESIGN: Population-based cohort study. SETTING: All 90 Dutch hospitals with obstetric/paediatric departments linked to community practices of midwives, general practitioners in their attachment areas, organised in perinatal cooperation groups (PCG). POPULATION: The population consisted of 943 registered term perinatal deaths occurring in 2010-2012 with detailed information, including 707 cases with completed audit results. MAIN OUTCOME MEASURES: Participation in the audit, perinatal death classification, identification of substandard factors (SSF), SSF in relation to death, conclusive recommendations for quality improvement in perinatal care and antepartum risk selection at the start of labour. RESULTS: After the introduction of the perinatal audit in 2010, all PCGs participated. They organised 645 audit sessions, with an average of 31 healthcare professionals per session. Of all 1102 term perinatal deaths (2.3/1000) data were registered for 86% (943) and standardised anonymised audit results for 64% (707). In 53% of the cases at least one SSF was identified. Non-compliance to guidelines (35%) and deviation from usual professional care (41%) were the most frequent SSF. There was a (very) probable relation between the SSF and perinatal death for 8% of all cases. This declined over the years: from 10% (n=23) in 2010 to 5% (n=10) in 2012 (p=0.060). Simultaneously term perinatal mortality decreased from 2.3 to 2.0/1000 births (p<0.00001). Possibilities for improvement were identified in the organisation of care (35%), guidelines or usual care (19%) and in documentation (15%). More pregnancies were antepartum selected as high risk, 70% in 2010 and 84% in 2012 (p=0.0001). CONCLUSIONS: The perinatal audit is implemented nationwide in all obstetrical units in the Netherlands in a short time period. It is possible that the audit contributed to the decrease in term perinatal mortality.

Ethnic disparities in perinatal mortality at 40 and 41 weeks of gestation.

OBJECTIVE: To evaluate whether maternal ethnicity affects perinatal mortality by week of gestation from 39 weeks onwards. STUDY DESIGN: In this cohort study, we used data from the nationwide Netherlands Perinatal Registry from 1999 until 2008. All singleton infants born between 39+0 and 42+6 weeks of gestation without congenital anomalies were included. We used crude and multivariate logistic regression analyses with white Europeans as the reference to calculate the adjusted odds ratios (aOR) of South Asian, African and Mediterranean women. The main outcome measure was perinatal mortality (antepartum and intrapartum/neonatal mortality within 7 days after birth). RESULTS: We studied 1,092,255 singleton deliveries. Perinatal mortality occurred in 2315 infants (2.1‰). There was interaction between gestational age and ethnicity (P<0.0001). In week 40 (40+0-40+6) South Asian (aOR 1.9; 95% CI 1.1-3.4) and Mediterranean (aOR 1.3; 95% CI 1.04-1.7) women had an increased risk of perinatal mortality. The perinatal mortality risk became greater in week 41 for South Asian (aOR 4.5 95% CI 2.8-7.2), African (aOR 2.2; 95%CI 1.4-3.4) and Mediterranean (aOR 2.2; 95% CI 1.8-2.9) women, especially among small for gestational age infants. CONCLUSION: With increasing gestational age beyond 39 weeks, perinatal mortality risk increases more strongly among South Asian, African and Mediterranean women compared to European whites.

[Differences in perinatal mortality between districts of Amsterdam]. / Perinatale sterfteverschillen in Amsterdam.

OBJECTIVE: To study the effect of district on perinatal mortality in Amsterdam, the Netherlands, taking into account various risk factors including ethnicity and social economic status (SES). DESIGN: Cohort study. METHOD: The investigation related to 73,661 singleton births in Amsterdam, Diemen and Ouder-Amstel recorded in the Netherlands Perinatal Registry over the years 2000-2006. Logistic regression analysis was used to determine if perinatal mortality differed by district, taking into account various risk factors. RESULTS: Each year in Amsterdam an average of 10,525 singleton children were born of whom 114 infants died (10.8 per 1,000 births (‰)). National perinatal mortality was 9.9 ‰. In three districts, perinatal mortality was 1.5-2 times higher than the national average: Zuidoost (21‰), Slotervaart (14‰) and Zeeburg (14‰). However, mortality in the districts of ZuiderAmstel (5‰), Oud-Zuid (7‰), Centrum and Osdorp (8‰) was 20-50% lower. The high risk of perinatal mortality in the Zuidoost district (odds ratio: 2.1; 95% CI: 1.9-2.6) was explained by the high prevalence of women with higher risk factors; African or South Asian Surinamese ethnicity, low SES and preterm birth. The effects of parity and ethnicity on perinatal mortality differed by district. In Zeeburg increased effect for higher parity and for Turkish/Moroccan ethnicity was seen. In Slotervaart the perinatal mortality risk was increased (odds ratio: 1.8; 95% CI: 1.3-2.5), but this was not explained by the risk factors studied. CONCLUSION: Amsterdam had districts with both highly elevated and reduced perinatal mortality rates. The prevalence of risk factors differed by district and the effects of ethnicity and parity were not homogenous. Therefore, tailored policy and research by district is necessary.