Association between gestational weight gain and preterm birth and post-term birth: a longitudinal study from the National Vital Statistics System database.

BACKGROUND: To evaluate the association between gestational weight gain (GWG) and preterm birth and post-term birth. METHODS: This longitudinal-based research studied singleton pregnant women from the National Vital Statistics System (NVSS) (2019). Total GWG (kg) was converted to gestational age-standardized z scores. The z-scores of GWG were divided into four categories according to the quartile of GWG, and the quantile 2 interval was used as the reference for the analysis. Univariate and multivariate logistic regression analyses were performed to investigate the association between GWG and preterm birth, post-term birth, and total adverse outcome (preterm birth + post-term birth). Subgroup analysis stratified by pre-pregnancy body mass index (BMI) was used to estimate associations between z-scores and outcomes. RESULTS: Of the 3,100,122 women, preterm birth occurred in 9.45% (292,857) population, with post-term birth accounting for 4.54% (140,851). The results demonstrated that low GWG z-score [odds ratio (OR): 1.04, 95% confidence interval (CI): 1.03 to 1.05, P < 0.001], and higher GWG z-scores (quantile 3: OR: 1.42, 95% CI: 1.41 to 1.44, P < 0.001; quantile 4: OR: 2.79, 95% CI: 2.76 to 2.82, P < 0.001) were positively associated with preterm birth. Low GWG z-score (OR: 1.18, 95% CI: 1.16 to 1.19, P < 0.001) was positively associated with an increased risk of post-term birth. However, higher GWG z-scores (quantile 3: OR: 0.84, 95% CI: 0.83 to 0.85, P < 0.001; quantile 4: 0.59, 95% CI: 0.58 to 0.60, P < 0.001) was associated with a decreased risk of post-term birth. In addition, low GWG z-score and higher GWG z-scores were related to total adverse outcome. A subgroup analysis demonstrated that pre-pregnancy BMI, low GWG z-score was associated with a decreased risk of preterm birth among BMI-obesity women (OR: 0.96, 95% CI: 0.94 to 0.98, P < 0.001). CONCLUSION: Our result suggests that the management of GWG may be an important strategy to reduce the number of preterm birth and post-term birth.

[Reducing rate of macrosomia in Iceland in relation to changes in the labor induction rate].

AIM: Diabetes and prolonged pregnancy are risk factors of macrosomia. The aim was to explore the relationship between the increased rate of labor induction and macrosomia in Iceland. Changes in the incidence proportion of macrosomia was estimated by gestational age. Further, the association between labor induction and macrosomia was estimated in reference to expectant management. MATERIAL AND METHODS: Data from the Iceland birth registry on 92,424 singleton births from 1997 to 2018 was used in this cohort study. Macrosomia was defined as birth weight more than 4.5 kg. The incidence proportion during three periods, 1997-2004, 2005-2011, 2012-2018, was calculated and stratified by gestational age. The relative risk reduction of macrosomia over time was calculated with log-binomial regression, using the first period as reference. The risk and relative risk of macrosomia compared with expectant management was estimated and adjusted for diabetes. RESULTS: The total number of macrosomic infants was 5110 and of those only 313 had a mother with diabetes. The incidence proportion of macrosomia was 6.5% during the period 1997-2004, but 4.6% during 2012-2018. A relative risk reduction of macrosomia over time was seen for deliveries after estimated due date. Labor induction decreased the risk of macrosomia, but the association persisted after adjustment for diabetes. CONCLUSION: The rate of macrosomia decreased in Iceland during the last two decades, but only a small proportion of macrosomic infants had a mother with diabetes. Labor induction decreased the risk of macrosomia, an association which seemed independent of diabetes.

Gestational age at birth and risk of intellectual disability without a common genetic cause.

Preterm birth is linked to intellectual disability and there is evidence to suggest post-term birth may also incur risk. However, these associations have not yet been investigated in the absence of common genetic causes of intellectual disability, where risk associated with late delivery may be preventable. We therefore aimed to examine risk of intellectual disability without a common genetic cause across the entire range of gestation, using a matched-sibling design to account for unmeasured confounding by shared familial factors. We conducted a population-based retrospective study using data from the Stockholm Youth Cohort (n = 499,621) and examined associations in a nested cohort of matched outcome-discordant siblings (n = 8034). Risk of intellectual disability was greatest among those born extremely early (adjusted OR24 weeks = 14.54 [95% CI 11.46-18.44]), lessening with advancing gestational age toward term (aOR32 weeks = 3.59 [3.22-4.01]; aOR37weeks = 1.50 [1.38-1.63]); aOR38 weeks = 1.26 [1.16-1.37]; aOR39 weeks = 1.10 [1.04-1.17]) and increasing with advancing gestational age post-term (aOR42 weeks = 1.16 [1.08-1.25]; aOR43 weeks = 1.41 [1.21-1.64]; aOR44 weeks = 1.71 [1.34-2.18]; aOR45 weeks = 2.07 [1.47-2.92]). Associations persisted in a cohort of matched siblings suggesting they were robust against confounding by shared familial traits. Risk of intellectual disability was greatest among children showing evidence of fetal growth restriction, especially when birth occurred before or after term. Birth at non-optimal gestational duration may be linked causally with greater risk of intellectual disability. The mechanisms underlying these associations need to be elucidated as they are relevant to clinical practice concerning elective delivery around term and mitigation of risk in post-term children.

Pregnancy before recurrent pregnancy loss more often complicated by post-term birth and perinatal death.

INTRODUCTION: The cause of recurrent pregnancy loss often remains unknown. Possibly, pathophysiological pathways are shared with other pregnancy complications. MATERIAL AND METHODS: All women with secondary recurrent pregnancy loss (SRPL) visiting Leiden University Medical Center (January 2000-2015) were included in this retrospective cohort to assess whether women with SRPL have a more complicated first pregnancy compared with control women. SRPL was defined as three or more consecutive pregnancy losses before 22 weeks of gestation, with a previous birth. The control group consisted of all Dutch nullipara delivering a singleton (January 2000-2015). Information was obtained from the Dutch Perinatal Registry. Outcomes were preeclampsia, preterm birth, post-term birth, intrauterine growth restriction, breach position, induction of labor, cesarean section, congenital abnormalities, perinatal death and severe hemorrhage in the first ongoing pregnancy. Subgroup analyses were performed for women with idiopathic SRPL and for women ≤35 years. RESULTS: In all, 172 women with SRPL and 1 196 178 control women were included. Women with SRPL were older and had a higher body mass index; 29.7 years vs. 28.8 years and 25.1 kg/m2 vs. 24.1 kg/m2 , respectively. Women with SRPL more often had a post-term birth (OR 1.86, 95% CI 1.10-3.17) and more perinatal deaths occurred in women with SRPL compared with the control group (OR 5.03, 95% CI 2.48-10.2). Similar results were found in both subgroup analyses. CONCLUSIONS: The first ongoing pregnancy of women with (idiopathic) SRPL is more often complicated by post-term birth and perinatal death. Revealing possible links between SRPL and these pregnancy complications might lead to a better understanding of underlying pathophysiology.

Gestational Age in Autistic Children and Adolescents: Prevalence and Effects on Autism Phenotype.

Pre- and post-term children show increased autism risk. Little is known about gestational age (GA) prevalence among autistic children, and their respective autism phenotype. We compared prevalence of pre-, full- and post-term birth between a population-derived sample of N = 606 (137 females, 22.61%) autistic children and adolescents (mean age = 14.01, SD = 3.63, range 3-24) from the Netherlands Autism Register, and matched controls from the Dutch birth register. Autism phenotype and comorbid symptoms were assessed with the AQ-short and SDQ questionnaires. Using logistic regression, we found higher prevalence of pre- and post-term birth among autistic individuals but no phenotypical differences across GA groups. Autism risk was particularly elevated for post-term children, highlighting the need for closer investigation of autism on the whole GA range.

Gestational age at birth and sleep duration in early childhood in three population-based cohorts.

BACKGROUND: Both preterm and post-term births have been associated with neonatal morbidity and mortality, including adverse impact on neurodevelopment. Important neural maturational processes take place during sleep in newborns, but findings on gestational duration and sleep in early childhood are contradictory and often derive from small clinical samples. We studied the association of gestational age at birth with sleep duration in early childhood in three population-based cohorts. METHODS: Gestational age at birth and sleep duration were assessed in three population-based cohort studies in The Netherlands (n = 6471), Singapore (n = 862), and Canada (n = 583). Gestational age at birth was assessed using ultrasound in pregnancy in combination with date of birth, and caregivers repeatedly reported on child sleep duration at three, six, 24, and 36 months of age. Generalized estimating equations were used, which were adjusted for confounders, and findings were pooled in a meta-analysis. RESULTS: Children born preterm (<37 weeks of gestation) showed longer sleep duration than children born at term; and children born post-term (≥42 weeks of gestation) showed shorter sleep duration. The meta-analysis indicated a small negative effect of gestational age on child sleep duration (effect size -0.11), when assessed in children born at term only. CONCLUSION: In early childhood, children with a lower gestational age have a longer sleep duration, even when they are born at term (37-42 weeks of gestation). These subtle yet consistent findings point to the importance of maturational processes during sleep, not only in premature children but also in children born at term after shorter gestational duration.

Short interpregnancy interval and adverse birth outcomes in women of advanced age: a population-based study.

PURPOSE: Short interpregnancy interval (IPI) has been linked with adverse birth outcomes. However, the association in advanced age women needs further investigation. This study aims to examine the association between short IPI and adverse birth outcomes including preterm birth, post-term birth, low birth weight, and macrosomia, in a population of advanced age U.S. women. METHODS: The 2016 U.S. public-use natality data was analyzed. Analysis was restricted to women with second-order singleton live births who were ≥35 years at first live birth (n = 46,684). Multinomial logistic regression analysis was used to examine the association between short IPI and adverse birth outcomes. RESULTS: Short IPI in advanced age women was significantly associated with higher odds of extremely preterm birth (0-5 months IPI: adjusted odds ratio [AOR] = 2.43, 95% confidence interval [CI] = 1.07-5.52; 6-11 months IPI: AOR = 2.17, 95% CI = 1.09-4.31), very preterm birth (0-5 months IPI: AOR = 1.63, 95% CI = 1.04-2.56), and extremely low birth weight (0-5 months IPI: AOR = 2.43, 95% CI = 1.28-4.60) in the second delivery. An inverse relationship between short IPI and post-term birth was observed and no significant association between short IPI and macrosomia was found. CONCLUSIONS: Short IPI in advanced age women increases the odds of adverse birth outcomes in the second delivery.