Trends in preterm birth in the Netherlands in 2011-2019: A population-based study among singletons and multiples.

INTRODUCTION: Preterm birth (PTB) is the leading cause of infant mortality and morbidity worldwide. Rates of PTB in the Netherlands are declining, possibly due to the implementation of preventive strategies. In this study we assessed the overall trend in PTB rates in the Netherlands in recent years, and in more detail in specific subgroups to investigate potential groups that require scrutiny in the near future. MATERIAL AND METHODS: Based on the national perinatal registry, we included all pregnancies without severe congenital abnormalities resulting in a birth from 24 to 42 completed weeks of gestation between 2011 and 2019 in the Netherlands. We assessed PTB rates in two different clinical subtypes (spontaneous vs. iatrogenic) and in five gestational age subgroups: 24-27+6 weeks (extreme), 28-31+6 weeks (very), 32-33+6 weeks (moderate, 34-36+6 weeks [late] and, in general, 24-36+6 weeks [overall PTB]). Trend analysis was performed using the Cochran Armitage test. We also compared PTB rates in different subgroups in the first 2 years compared to the last 2 years. Singleton and multiple gestations were analyzed separately. RESULTS: We included 1 447 689 singleton and 23 250 multiple pregnancies in our study. In singletons, we observed a significant decline in PTB from 5.5% to 5.0% (p < 0.0001), mainly due to a decrease in iatrogenic PTBs. When focusing on different gestational age subgroups, there was a decrease in all iatrogenic PTB and in moderate to late spontaneous PTB. However, in spontaneous extreme and very PTB there was an significant increase. When assessing overall PTB risk in different subgroups, the decline was only visible in women with age ≥25 years, nulliparous and primiparous women, women with a medium or high socioeconomic status and hypertensive women. In multiples, the rate of PTB remained fairly stable, from 52.3% in 2011 to 54.1% in 2019 (p = 0.57). CONCLUSIONS: In the Netherlands, between 2011 and 2019, PTB decreased, mainly due to a reduction in late PTB, and more in iatrogenic than in spontaneous PTB. Focus for the near future should be on specific subgroups in which the decline was not visible, such as women with a low socioeconomic status or a young age.

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.

Offspring school performance at age 12 after induction of labor vs non-intervention at term: A linked cohort study.

INTRODUCTION: The incidence of induction of labor, for both medical reasons and as an elective procedure, has been rising and a further increase in induction of labor following the ARRIVE trial may be expected. The effects of induction of labor at term on childhood neurodevelopment, however, are not well studied. We aimed to study the influence of elective induction of labor for each week of gestation separately from 37 to 42 weeks on offspring school performance at 12 years of age after uncomplicated pregnancies. MATERIAL AND METHODS: We performed a population-based study among 226 684 liveborn children from uncomplicated singleton pregnancies, born from 37+0 to 42+0 weeks of gestation in cephalic presentation in 2003-2008 (no hypertensive disorders, diabetes or birthweight ≤p5) in the Netherlands. Children with congenital anomalies, of non-white mothers and born after planned cesarean section were excluded. Birth records were linked with national data on school achievement. We compared, using a fetus-at-risk approach and per week of gestation, school performance score and secondary school level at age 12 in those born after induction of labor to those born after non-intervention, ie spontaneous onset of labor in the same week plus all those born at later gestations. Education scores were standardized to a mean of 0 and a standard deviation of 1 and adjusted in the regression analyses. RESULTS: For each gestational age up to 41 weeks, induction of labor was associated with decreased school performance scores compared with non-intervention (at 37 weeks -0.05 SD, 95% confidence interval [CI] -0.10 to -0.01 SD; adjusted for confounding factors). After induction of labor, fewer children reached higher secondary school level (at 38 weeks 48% vs 54%; adjusted odds ratio [aOR] 0.88, 95% CI 0.82-0.94). CONCLUSIONS: In women with uncomplicated pregnancies at term, consistently, at every week of gestation from 37 to 41 weeks, induction of labor is associated with lower offspring school performance at age 12 and lower secondary school level compared with non-intervention, although residual confounding may remain. These long-term effects of induction of labor should be incorporated in counseling and decision making.

Preterm Birth is Associated with Lower Academic Attainment at Age 12 Years: A Matched Cohort Study by Linkage of Population-Based Datasets.

OBJECTIVE: To compare academic attainment at age 12 years in preterm children born below 30 weeks of gestation with matched term-born peers, using standardized, nationwide and well-validated school tests. STUDY DESIGN: This population-based, national cohort study was performed by linking perinatal data from the nationwide Netherlands Perinatal Registry with educational outcome data from Statistics Netherlands and included 4677 surviving preterm children born at 250/7-296/7 weeks of gestational age and 366 561 controls born at 40 weeks of gestational age in 2000-2007. First, special education participation rate was calculated. Subsequently, all preterm children with academic attainment test data derived at age 12 years were matched to term-born children using year and month of birth, sex, parity, socioeconomic status, and maternal age. Total, language, and mathematics test scores and secondary school level advice were compared between these 2 groups. RESULTS: Children below 30 weeks of gestation had a higher special education participation rate (10.2% vs 2.7%, P < .001) than term-born peers. Preterm children had lower total (-0.37 SD; 95% CI -0.42 to -0.31), language (-0.21 SD; 95% CI -0.27 to -0.15), and mathematics (-0.45 SD; 95%CI -0.51 to -0.38) z scores, and more often a prevocational secondary school level advice (62% vs 46%, P < .001). CONCLUSIONS: A substantial proportion of children born before 30 weeks of gestation need special education at the end of elementary schooling. These children have significant deficits on all measures of academic attainment at age 12 years, especially mathematics, compared with matched term-born peers.

Development and validation of a prediction model for early mortality after transcatheter aortic valve implantation (TAVI) based on the Netherlands Heart Registration (NHR): The TAVI-NHR risk model.

BACKGROUND: The currently available mortality prediction models (MPM) have suboptimal performance when predicting early mortality (30-days) following transcatheter aortic valve implantation (TAVI) on various external populations. We developed and validated a new TAVI-MPM based on a large number of predictors with recent data from a national heart registry. METHODS: We included all TAVI-patients treated in the Netherlands between 2013 and 2018, from the Netherlands Heart Registration. We used logistic-regression analysis based on the Akaike Information Criterion for variable selection. We multiply imputed missing values, but excluded variables with >30% missing values. For internal validation, we used ten-fold cross-validation. For temporal (prospective) validation, we used the 2018-data set for testing. We assessed discrimination by the c-statistic, predicted probability accuracy by the Brier score, and calibration by calibration graphs, and calibration-intercept and calibration slope. We compared our new model to the updated ACC-TAVI and IRRMA MPMs on our population. RESULTS: We included 9144 TAVI-patients. The observed early mortality was 4.0%. The final MPM had 10 variables, including: critical-preoperative state, procedure-acuteness, body surface area, serum creatinine, and diabetes-mellitus status. The median c-statistic was 0.69 (interquartile range [IQR] 0.646-0.75). The median Brier score was 0.038 (IQR 0.038-0.040). No signs of miscalibration were observed. The c-statistic's temporal-validation was 0.71 (95% confidence intervals 0.64-0.78). Our model outperformed the updated currently available MPMs ACC-TAVI and IRRMA (p value < 0.05). CONCLUSION: The new TAVI-model used additional variables and showed fair discrimination and good calibration. It outperformed the updated currently available TAVI-models on our population. The model's good calibration benefits preprocedural risk-assessment and patient counseling.

Stillbirth and neonatal mortality in a subsequent pregnancy following stillbirth: a population-based cohort study.

BACKGROUND: A history of stillbirth is a risk factor for recurrent fetal death in a subsequent pregnancy. Reported risks of recurrent fetal death are often not stratified by gestational age. In subsequent pregnancies increased rates of medical interventions are reported without evidence of perinatal benefit. The aim of this study was to estimate gestational-age specific risks of recurrent stillbirth and to evaluate the effect of obstetrical management on perinatal outcome after previous stillbirth. METHODS: A retrospective cohort study in the Netherlands was designed that included 252.827 women with two consecutive singleton pregnancies (1st and 2nd delivery) between 1999 and 2007. Data was obtained from the national Perinatal Registry and analyzed for pregnancy outcomes. Fetal deaths associated with a congenital anomaly were excluded. The primary outcome was the occurrence of stillbirth in the second pregnancy stratified by gestational age. Secondary outcome was the influence of obstetrical management on perinatal outcome in a subsequent pregnancy. RESULTS: Of 252.827 first pregnancies, 2.058 pregnancies ended in a stillbirth (8.1 per 1000). After adjusting for confounding factors, women with a prior stillbirth have a two-fold higher risk of recurrence (aOR 1.96, 95% CI 1.07-3.60) compared to women with a live birth in their first pregnancy. The highest risk of recurrence occurred in the group of women with a stillbirth in early gestation between 22 and 28 weeks of gestation (a OR 2.25, 95% CI 0.62-8.15), while after 32 weeks the risk decreased. The risk of neonatal death after 34 weeks of gestation is higher in women with a history of stillbirth (aOR 6.48, 95% CI 2.61-16.1) and the risk of neonatal death increases with expectant obstetric management (aOR 10.0, 95% CI 2.43-41.1). CONCLUSIONS: A history of stillbirth remains an important risk for recurrent stillbirth especially in early gestation (22-28 weeks). Women with a previous stillbirth should be counselled for elective induction in the subsequent pregnancy at 37-38 weeks of gestation to decrease the risk of perinatal death.

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.

The association between parity and spontaneous preterm birth: a population based study.

BACKGROUND: Preterm birth is the leading cause of perinatal mortality and neonatal morbidity worldwide. Many factors have been associated with preterm birth, including parity. The aim of the present study was to investigate associations between parity and risk of spontaneous preterm birth. METHODS: We conducted a retrospective study including live singleton births (≥22 weeks) of women with a first, second, third, fourth or fifth pregnancy in The Netherlands from 2010 through 2014. Our primary outcome was risk of spontaneous preterm birth < 37 weeks. Secondary outcomes were spontaneous preterm birth < 32 and < 28 weeks. RESULTS: We studied 802,119 pregnancies, including 30,237 pregnancies that ended spontaneously < 37 weeks. We identified an increased risk for spontaneous preterm birth < 37 weeks in nulliparous women (OR 1.95, 95% CI 1.89-2.00) and women in their fifth pregnancy (OR 1.26, 95% CI 1.13-1.41) compared to women in their second pregnancy. Similar results were seen for spontaneous preterm birth < 32 and < 28 weeks. CONCLUSION: Our data show an independent association between nulliparity and spontaneous preterm birth < 37, < 32 and < 28 weeks. Furthermore, we observed an increased risk for spontaneous preterm birth in women in their fifth pregnancy, with highest risk for preterm birth at early gestational age.

Association between fetal sex, birthweight percentile and adverse pregnancy outcome.

INTRODUCTION: The objective was to evaluate the association between fetal sex and adverse pregnancy outcome, while correcting for fetal growth and gestational age at delivery. MATERIAL AND METHODS: Data from the Netherlands Perinatal Registry (1999-2010) were used. The study population comprised all white European women with a singleton delivery between 25+0 and 42+6  weeks of gestation. Fetuses with structural or chromosomal abnormalities were excluded. Outcomes were antepartum death, intrapartum/neonatal death (from onset of labor until 28 days after birth), perinatal death (antepartum death or intrapartum/neonatal death), a composite of neonatal morbidity (including infant respiratory distress syndrome, sepsis, necrotizing enterocolitis, meconium aspiration, persistent pulmonary hypertension of the newborn, periventricular leukomalacia, Apgar score <7 at 5 minutes, and intracranial hemorrhage) and a composite adverse neonatal outcome (perinatal death or neonatal morbidity). Outcomes were expressed stratified by birthweight percentile (p90 [large for gestation]) and gestational age at delivery (25+0 -27+6 , 28+0 -31+6 , 32+0 -36+6 , 37+0 -42+6  weeks). The association between fetal sex and outcome was assessed using the fetus at risk approach. RESULTS: We studied 1 742 831 pregnant women. We found no increased risk of antepartum, intrapartum/neonatal and perinatal death in normal weight and large-for-gestation males born after 28+0  weeks compared with females. We found an increased risk of antepartum death among small-for-gestation males born after 28+0  weeks (relative risk [RR] 1.16-1.40). All males born after 32+0  weeks of gestation suffered more neonatal morbidity than females regardless of birthweight percentile (RR 1.07-1.34). Infant respiratory distress syndrome, sepsis, persistent pulmonary hypertension of the newborn, Apgar score <7 at 5 minutes, and intracranial hemorrhage all occurred more often in males than in females. CONCLUSIONS: Small-for-gestation males have an increased risk of antepartum death and all males born after 32+0  weeks of gestation have an increased risk of neonatal morbidity compared with females. In contrast to findings in previous studies we found no increased risk of antepartum, intrapartum/neonatal or perinatal death in normal weight and large-for-gestation males born after 28+0  weeks.

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.

Increased postpartum haemorrhage, the possible relation with serotonergic and other psychopharmacological drugs: a matched cohort study.

BACKGROUND: Postpartum haemorrhage is a major obstetric risk worldwide. Therefore risk factors need to be investigated to control for this serious complication. A recent systematic review and meta-analysis revealed that the use of both serotonergic and non-serotonergic antidepressants in pregnancy are associated with a higher risk of postpartum haemorrhage. However, use of antidepressants in pregnancy is often necessary because untreated depression in pregnancy is associated with adverse maternal and neonatal outcome, such as postpartum depression, preterm birth and dysmaturity. Therefore it is of utmost importance to unravel the possible association between postpartum haemorrhage and the use of serotonergic and other psychopharmacological medication during pregnancy. METHODS: We performed a matched cohort observational study consecutively including all pregnant women using serotonergic medication (n = 578) or other psychopharmacological medication (n = 50) visiting two teaching hospitals in Amsterdam between 2010 and 2014. The incidence of postpartum haemorrhage in women using serotonergic medication or other psychopharmacological medication was compared with the incidence of postpartum haemorrhage in 641,364 pregnant women not using psychiatric medication selected from the database of the Netherlands Perinatal Registry foundation (Perined). Matching took place 1:5 for nine factors, i.e., parity, maternal age, ethnicity, socioeconomic status, macrosomia, gestational duration, history of postpartum haemorrhage, labour induction and hypertensive disorder. RESULTS: Postpartum haemorrhage occurred in 9.7% of the women using serotonergic medication. In the matched controls this was 6.6% (p = 0.01). The adjusted odds ratio (aOR) before matching was 1.6 (95% CI 1.2-2.1) and after matching 1.5 (95% CI 1.1-2.1). Among the women using other psychopharmacological medication, the incidence of postpartum haemorrhage before matching was 12.0% versus 6.1% (p = 0.08) with OR 2.1 (95% CI 0.9-4.9), and after matching 12.1% versus 4.4% (p = 0.03) with aOR of 3.3 (95% CI 1.1-9.8). CONCLUSIONS: Pregnant women using serotonergic medication have an increased risk of postpartum haemorrhage, but this high risk is also seen in pregnant women using other psychopharmacological medication. We suggest that this higher risk of postpartum haemorrhage could not only be explained by serotonin, but also by other mechanisms. An additional explanation could be the underlying psychiatric disorder.

The Effect of Interpregnancy Interval on the Recurrence Rate of Spontaneous Preterm Birth: A Retrospective Cohort Study.

Objective We assessed, in women with a previous spontaneous preterm birth, the effect of interpregnancy interval on the subsequent preterm birth rate. Design Retrospective cohort study. Setting A nationwide longitudinal dataset of the the Netherlands Perinatal Registry. Population Women with three sequential singleton pregnancies between 1999 and 2009 and a spontaneous preterm birth <37 weeks in the first pregnancy. Methods We evaluated the impact of interpregnancy interval on the course of the next pregnancies. Antenatal death and/or congenital abnormalities were excluded. Conventional and conditional logistic regression analysis were applied. We adjusted for maternal age, ethnicity, socioeconomic status, artificial reproductive techniques, and year of birth. Main Outcome Measures Outcomes studied were preterm birth <37 weeks, <32 weeks, low birth weight <2500 g, and small for gestational age <10th percentile. Results Among 2,361 women with preterm birth in the first pregnancy, logistic regression analysis indicated a significant effect of a short interpregnancy interval (0-5 mo) on recurrent preterm birth <37 weeks (odds ratio [OR], 2.22; 95% confidence interval [CI], 1.62-3.05), <32 weeks (OR, 2.90; 95% CI, 1.43-5.87), and low birth weight (OR, 2.69; 95% CI, 1.79-4.03). In addition, a long interval (≥60 mo) had a significant effect on preterm birth <37 weeks (OR, 2.19; 95% CI, 1.29-3.74). Conditional logistic regression analysis confirmed the effect of a short interval on the recurrence of preterm birth rate <37 weeks and low birth weight. Conclusion In women with a previous spontaneous preterm birth, a short interpregnancy interval has a strong impact on the risk of preterm birth before 37 weeks and low birth weight in the next pregnancy, irrespective of the type of analysis performed.

Impact of fetal gender on the risk of preterm birth, a national cohort study.

INTRODUCTION: Fetal gender is associated with preterm birth; however, a proper subdivision by onset of labor and corresponding neonatal outcome by week of gestation is lacking. MATERIAL AND METHODS: Data from the Netherlands Perinatal Registry (1999-2010) were used to calculate relative risk ratios for gender by week of gestation and gender-related risk on adverse neonatal outcomes using a moving average technique. White European women with an alive fetus at onset of labor were included. Adverse neonatal outcomes were defined as neonatal mortality and a composite of neonatal morbidity. Onset of labor was categorized as spontaneous onset with intact membranes, premature rupture of membranes, and induction or elective cesarean section. RESULTS: The study population comprised 1 736 615 singleton deliveries (25(+0) -42(+6) weeks). Male fetuses were at increased risk of spontaneous preterm birth with intact membranes compared with a female fetus with a peak between 27 and 31 weeks [relative risk (RR) 1.5; 95% CI 1.4-1.6]. Male fetuses were also at increased risk of preterm premature rupture of membranes between 27 and 37 weeks (RR 1.2; 95% CI 1.16-1.23). No gender effect was seen for medically indicated preterm birth. No significant differences were seen for neonatal mortality. Males were at significantly increased risk of composite neonatal morbidity from 29 weeks onwards (RR 1.3; 95% CI 1.3-1.4). CONCLUSIONS: Male fetal gender is a relevant risk factor for spontaneous preterm birth, both for intact membranes and for preterm premature rupture of membranes in white European women. In addition, male infants are at increased risk of neonatal morbidity.

Incidence and recurrence rate of placental abruption: a longitudinal linked national cohort study in the Netherlands.

OBJECTIVE: Women who have experienced a placental abruption have a risk of recurrence, but exact information to quantify this risk is currently not available. We studied the incidence and recurrence rate of placental abruption in a subsequent pregnancy and the influence of hypertensive disorders. STUDY DESIGN: We conducted a retrospective national cohort study of all singleton pregnancies that ended from 1999-2007 in the Netherlands. A longitudinal linked national cohort of these women with information on a subsequent singleton delivery was used. We calculated and compared incidence and recurrence rates of placental abruption for women in total, stratified by gestational age of first placental abruption and by the presence of a hypertensive disorder in their first pregnancy. RESULTS: We studied 1,570,635 women of which 3496 (0.22%) experienced a placental abruption. Information was available on a subsequent singleton delivery for 264,424 deliveries. Of these, 521 women (0.20%) had a placental abruption in the first pregnancy vs 214 women (0.08%) in the second pregnancy. The risk of placental abruption in a subsequent pregnancy was significantly higher in women with a previous placental abruption compared with women without (5.8% vs 0.06%; adjusted odds ratio [aOR], 93; 95% confidence interval [CI], 62-139). Women with a placental abruption that occurred at term in their first pregnancy were more at risk for recurrence (aOR, 188; 95% CI, 116-306) than women with a preterm (aOR, 52; 95% CI, 25-111) or early preterm (<32 weeks of gestation) placental abruption in their first pregnancy (aOR, 39; 95% CI, 13-116). Placental abruption was more frequent among women with a hypertensive disorder compared with normotensive women (0.44% vs 0.16%; odds ratio, 2.7; 95% CI, 2.3-3.3). Women with a hypertensive disorder were less at risk for recurrence than were normotensive women (aOR, 0.68; 95% CI, 0.27-1.6). No interaction between a hypertensive disorder in the first pregnancy and the recurrence risk was found. CONCLUSION: Women with a placental abruption in their first pregnancy have a greatly increased risk of placental abruption in a subsequent pregnancy. Hypertensive disorders increase the risk of placental abruption but do not increase the recurrence rate in a subsequent pregnancy. We suggest elective induction from 37 weeks of gestation for women with a history of placental abruption at term in a previous pregnancy.

Maternal and neonatal outcomes of pregnancy in women with chronic hypertension: a retrospective analysis of a national register.

INTRODUCTION: Pregnancies complicated by chronic hypertension are at increased risk of adverse pregnancy outcomes. To assess whether planned early delivery might prevent some of these adverse outcomes, we studied maternal and neonatal outcomes of pregnancy in women with chronic hypertension, including gestational-age-specific outcomes. MATERIAL AND METHODS: We performed a retrospective, population-based cohort study, using data from the Netherlands Perinatal Register. We included women with chronic hypertension and normotensive controls who delivered a singleton without congenital anomalies in 2002-2007. We calculated crude and adjusted odds ratios (OR) with 95% CI, compared delivery and ongoing pregnancy using moving averages, and used multiple Cox regression to adjust for differences in baseline characteristics and to examine adverse neonatal outcomes across subgroups of hypertensive disorder. Main outcome measures were composite adverse maternal and neonatal outcomes. RESULTS: We included 3457 (0.3%) women with chronic hypertension and 984 932 normotensive controls. Women with chronic hypertension had adverse maternal outcomes more often (28.7% vs. 6.6%, adjusted OR 5.7, 95% CI 5.3-6.2). Their offspring had an increased rate of neonatal morbidity (17.4% vs. 13.2%, adjusted OR 1.2, 95% CI 1.1-1.4) but not of severe adverse neonatal outcomes (2.5% vs. 2.2%, adjusted OR 0.8, 95% CI 0.6-1.0). The increased risk of adverse maternal outcomes for ongoing pregnancy remained stable around 17% at term. The risk of severe adverse neonatal outcomes for birth was at its lowest between 38 and 40 weeks, mainly in women with iatrogenic onset of delivery. CONCLUSIONS: Women with chronic hypertension are at increased risk of adverse maternal and neonatal outcomes compared with controls throughout pregnancy, including at term. Our results suggest that the optimal timing of delivery might be between 38 and 40 weeks of gestation, but prospective randomized studies should confirm this.

The Relation between Duration of Ruptured Membranes and Perinatal Outcome in Patients with Midtrimester Prelabor Rupture of Membranes.

OBJECTIVE: The aim of the study was to assess the impact of gestational age (GA) at rupture and latency on perinatal outcome after midtrimester prelabor rupture of membranes (PROM). STUDY DESIGN: We obtained data on singleton pregnancies from 22 weeks onwards from the Dutch Perinatal Registry from 1999 to 2007, congenital abnormalities were excluded. In women with PROM before 26 weeks, we studied the impact of GA at rupture and latency on perinatal mortality and morbidity. RESULTS: A total of 1,233 pregnancies were included. Higher GA at delivery appeared to increase the probability of survival without morbidity, GA at PROM did not. In pregnancies of minimum 22 weeks GA, there appeared to be no clear relationship between earlier GA at PROM and adverse outcome. CONCLUSION: Longer latency and early GA at PROM seem to have limited impact in patients delivering after 22 weeks.

Adaptive list sequential sampling method for population-based observational studies.

BACKGROUND: In population-based observational studies, non-participation and delayed response to the invitation to participate are complications that often arise during the recruitment of a sample. When both are not properly dealt with, the composition of the sample can be different from the desired composition. Inviting too many individuals or too few individuals from a particular subgroup could lead to unnecessary costs or decreased precision. Another problem is that there is frequently no or only partial information available about the willingness to participate. In this situation, we cannot adjust the recruitment procedure for non-participation before the recruitment period starts. METHODS: We have developed an adaptive list sequential sampling method that can deal with unknown participation probabilities and delayed responses to the invitation to participate in the study. In a sequential way, we evaluate whether we should invite a person from the population or not. During this evaluation, we correct for the fact that this person could decline to participate using an estimated participation probability. We use the information from all previously invited persons to estimate the participation probabilities for the non-evaluated individuals. RESULTS: The simulations showed that the adaptive list sequential sampling method can be used to estimate the participation probability during the recruitment period, and that it can successfully recruit a sample with a specific composition. CONCLUSIONS: The adaptive list sequential sampling method can successfully recruit a sample with a specific desired composition when we have partial or no information about the willingness to participate before we start the recruitment period and when individuals may have a delayed response to the invitation.