Maternal risk factors and adverse birth outcomes associated with HELLP syndrome: a population-based study.

OBJECTIVES: We assessed the incidence, risk factors and adverse birth outcomes associated with elevated liver enzymes and low platelets (HELLP) syndrome. DESIGN: A retrospective population-based cohort study. SETTING: Canada (excluding Quebec), 2012/2013-2015/2016. POPULATION: Mothers with a singleton hospital live birth or stillbirth at ≥24 weeks' gestation (n = 1 078 323). METHODS: HELLP syndrome was identified using ICD-10-CA diagnostic code from delivery hospitalisation data. We used logistic regression to identify independent risk factors for HELLP syndrome by obtaining adjusted odds ratios (AOR) and 95% confidence intervals (CI), and to assess the associations with adverse outcomes. MAIN OUTCOME MEASURES: Adverse maternal (e.g. eclampsia) and fetal/neonatal outcomes (e.g. intraventricular haemorrhage, perinatal death). RESULTS: The incidence of HELLP syndrome was 2.5 per 1000 singleton deliveries (n = 2663). Risk factors included: age ≥35 years, rural residence, nulliparity, parity ≥4, pre-pregnancy and gestational hypertension and diabetes, assisted reproduction, chronic cardiac conditions, systemic lupus erythematosus, obesity, chronic hepatic conditions, placental disorders (e.g. fetomaternal transfusion) and congenital anomalies. PROM and age <25 years were inversely associated with HELLP syndrome (P-values <0.05). Women with the syndrome had a 10-fold higher maternal mortality (95% CI 1.6-84.3) and elevated severe maternal morbidity (9.6 versus 121.7 per 1000; AOR 12.5, 95% CI 11.1-14.1); and higher perinatal mortality (4.3 versus 21.0 per 1000; AOR 4.5, 95% CI 3.5-5.9) and perinatal mortality/severe neonatal morbidity (21.2 versus 202.4 per 1000; AOR 10.7, 95% CI 9.7-11.8). CONCLUSION: HELLP syndrome is associated with specific pre-pregnancy and pregnancy risk factors, higher rates of maternal death, and substantially higher severe maternal morbidity, perinatal mortality and severe neonatal morbidity. TWEETABLE ABSTRACT: HELLP syndrome is associated with higher maternal death rate, and substantially higher severe maternal and neonatal morbidity, and perinatal mortality.

Perinatal and maternal morbidity and mortality among term singletons following midcavity operative vaginal delivery versus caesarean delivery.

OBJECTIVE: To quantify severe perinatal and maternal morbidity/mortality associated with midcavity operative vaginal delivery compared with caesarean delivery. DESIGN: Population-based, retrospective cohort study. SETTING: British Columbia, Canada. POPULATION: Term, singleton deliveries (2004-2014) by attempted midcavity operative vaginal delivery or caesarean delivery in the second stage of labour, stratified by indication for operative delivery (n = 10 901 deliveries; 5057 indicated for dystocia, 5844 for fetal distress). METHODS: Multinomial propensity scores and mulitvariable log-binomial regression models were used to estimate adjusted rate ratios (ARR) and 95% confidence intervals (95% CI). MAIN OUTCOME MEASURES: Composite severe perinatal morbidity/mortality (e.g. convulsions, severe birth trauma and perinatal death) and severe maternal morbidity (e.g. severe postpartum haemorrhage, shock, sepsis and cardiac complications). RESULTS: Among deliveries with dystocia, attempted midcavity operative vaginal delivery was associated with higher rates of severe perinatal morbidity/mortality compared with caesarean delivery (forceps ARR 2.11, 95% CI 1.46-3.07; vacuum ARR 2.71, 95% CI 1.49-3.15; sequential ARR 4.68, 95% CI 3.33-6.58). Rates of severe maternal morbidity/mortality were also higher following midcavity operative vaginal delivery (forceps ARR 1.57, 95% CI 1.05-2.36; vacuum ARR 2.29, 95% CI 1.57-3.36). Among deliveries with fetal distress, there were significant increases in severe perinatal morbidity/mortality following attempted midcavity vacuum (ARR 1.28, 95% CI 1.04-1.61) and in severe maternal morbidity following attempted midcavity forceps delivery (ARR 2.34, 95% CI 1.54-3.56). CONCLUSION: Attempted midcavity operative vaginal delivery is associated with higher rates of severe perinatal morbidity/mortality and severe maternal morbidity, though these effects differ by indication and instrument. TWEETABLE ABSTRACT: Perinatal and maternal morbidity is increased following midcavity operative vaginal delivery.

International comparisons of preterm birth: higher rates of late preterm birth are associated with lower rates of stillbirth and neonatal death.

OBJECTIVE: To examine international rates of preterm birth and potential associations with stillbirths and neonatal deaths at late preterm and term gestation. DESIGN: Ecological study. SETTING: Canada, USA and 26 countries in Europe. POPULATION: All deliveries in 2004. METHODS: Information on preterm birth (<37, 32-36, 28-31 and 24-27 weeks of gestation) and perinatal deaths was obtained for 28 countries. Data sources included files and publications from Statistics Canada, the EURO-PERISTAT project and the National Center for Health Statistics. Pearson correlation coefficients and random-intercept Poisson regression were used to examine the association between preterm birth rates and gestational age-specific stillbirth and neonatal death rates. Rate ratios with 95% confidence intervals were estimated after adjustment for maternal age, parity and multiple births. MAIN OUTCOME MEASURES: Stillbirths and neonatal deaths ≥ 32 and ≥ 37 weeks of gestation. RESULTS: International rates of preterm birth (<37 weeks) ranged between 5.3 and 11.4 per 100 live births. Preterm birth rates at 32-36 weeks were inversely associated with stillbirths at ≥ 32 weeks (adjusted rate ratio 0.94, 95% CI 0.92-0.96) and ≥ 37 weeks (adjusted rate ratio 0.88, 95% CI 0.85-0.91) of gestation and inversely associated with neonatal deaths at ≥ 32 weeks (adjusted rate ratio 0.88, 95% CI 0.85-0.91) and ≥ 37 weeks (adjusted rate ratio 0.82, 95% CI 0.78-0.86) of gestation. CONCLUSIONS: Countries with high rates of preterm birth at 32-36 weeks of gestation have lower stillbirth and neonatal death rates at and beyond 32 weeks of gestation. Contemporary rates of preterm birth are indicators of both perinatal health and obstetric care services.

Effect of older maternal age on birth outcomes in twin pregnancies: a population-based study.

OBJECTIVE: We compared perinatal mortality, preterm birth (<37, <33 and <28 weeks), small for gestational age (SGA), Apgar score (<4), mechanical ventilation (1 days) and prolonged neonatal intensive care unit (NICU) hospitalization (13 days) between twins of 25 to 34 and >35-year-old women. Further, we examined whether older maternal age effects were modified by parity or otherwise affected by chorionicity. STUDY DESIGN: We carried out a population-based retrospective cohort study including all twin births in British Columbia (BC), Canada, from 1999 to 2003. The BC perinatal database registry was used to obtain clinical, behavioral and demographic data. Adjusted odds ratios (OR) with 95% confidence intervals (CI) were calculated using generalized estimating equation models. RESULT: Overall, twins of older women were more likely to be born preterm (<37 weeks), but not very or extremely preterm (<33 weeks). These twins were not at increased risk of perinatal death, mechanical ventilation or were not SGA compared with twins of younger women. Twins of older primiparous women did not have an elevated risk of NICU hospitalization; twins born to older multiparous women had higher risk (OR=1.8; 95% CI: 1.2 to 2.6). Analyses restricted to opposite-sex (dichorionic) twins showed that perinatal death, mechanical ventilation and very preterm birth occur less likely among older women (OR=0.2 (95% CI: 0.0 to 0.8), OR=0.3 (95% CI: 0.1 to 0.7) and OR=0.4 (95% CI: 0.2 to 0.7), respectively). Further, the risk of late preterm birth was increased and NICU hospitalization was reduced among opposite-sex twins born to older compared with younger primiparous women (OR=1.9 (95% CI: 1.3 to 2.8) and OR=0.2 (95% CI: 0.1 to 0.5), respectively). CONCLUSION: Twins of older mothers did not have an elevated risk for most adverse birth outcomes, except for late preterm birth. Risks of neonatal care admission may be elevated among older multiparous women.

Optimal timing of delivery in pregnancies with pre-existing hypertension.

OBJECTIVE: To determine the optimal timing of delivery in pregnancies with pre-existing (chronic) hypertension by quantifying the gestational age-specific risks of stillbirth associated with ongoing pregnancy and the gestational age-specific risks of neonatal mortality or serious neonatal morbidity following the induction of labour. DESIGN: Population-based cohort study. SETTING: USA. POPULATION: A total of 171 669 singleton births to women with pre-existing hypertension between 1995 and 2005. Pregnancies additionally complicated by diabetes mellitus, cardiac, pulmonary or renal disease were excluded. METHODS: The week-specific risks of stillbirth between 36 and 41 completed weeks of gestation were contrasted with the week-specific risks of neonatal mortality or serious neonatal morbidity among births following induction of labour in women with pre-existing hypertension. MAIN OUTCOME MEASURES: Stillbirth, neonatal mortality or serious neonatal morbidity (defined as a composite outcome which included any of the following: neonatal seizures, severe respiratory morbidity or 5-minute Apgar score ≤3). RESULTS: The risk of stillbirth in women with pre-existing hypertension remained stable at 1.0-1.1 per 1000 ongoing pregnancies until 38 weeks, before rising steadily to 3.5 per 1000 [95% confidence interval (CI): 2.4, 5.0] at 41 weeks. The risk of serious neonatal morbidity/neonatal mortality decreased sharply between 36 and 38 weeks from 137 [95% CI: 127, 146] to 26 [95% CI: 24, 29] per 1000 induced births, before stabilising beyond 39 weeks. CONCLUSIONS: Among women with otherwise uncomplicated pre-existing hypertension, delivery at 38 or 39 weeks appears to provide the optimal trade-off between the risk of adverse fetal and adverse neonatal outcomes.

Timing of delivery for pregnancies with congenital diaphragmatic hernia.

A recent report has suggested that delivery at early term ages may be associated with lower mortality among infants with congenital diaphragmatic hernia. We sought to confirm this finding by examining gestational age-specific mortality in the USA in term infants with isolated congenital diaphragmatic hernia, delivered following the spontaneous onset of labour. In the final population of 928 infants, neonatal and infant mortality decreased with advancing gestation, from 25 and 36% at 37 weeks of gestation, respectively, to 17 and 20% at 40 weeks of gestation, respectively. Log-binomial regression models showed that neonatal and infant mortality at 37 weeks of gestation were significantly higher than at 40 weeks. Further evidence, ideally from a randomised trial, is needed before recommendations for clinical practice on timing of delivery should be made.

Perinatal characteristics and parents' perspective of health status of NICU graduates born at term.

OBJECTIVE: Long-term outcomes of preterm infants have been extensively studied, but few studies have examined long-term outcomes of term infants who require neonatal intensive care unit (NICU). Our objectives were to assess perinatal characteristics and health status of preschool age term babies using data from a population-based study of NICU graduates. STUDY DESIGN: Retrospective cross-sectional survey. All babies were born in 1996 to 1997 in BC (Canada). The Health Status Classification System Preschool (HSCS-PS) questionnaire was completed by parents at 42 months of age. HSCS-PS was grouped in four categories (neurosensory, learning, motor and quality of life). Logistic regression was used to identify perinatal risk factors associated with moderate/severe problems at 42 months of age. RESULT: Completed surveys were received for 261 term NICU survivors and 393 control children. Term infants represent 32% of all NICU admissions. Mean birth weight of NICU graduates was 3458 g (s.d.=600 g). Median length-of-stay in NICU was 5 days. At 42 months, the NICU group had significantly more problems on the HSCS-PS as compared to the full-term healthy infants in neurosensory, motor and learning/remembering. Moderate/severe health status problems were associated with congenital anomalies (odds ratio (OR), 3.2; confidence interval (CI): 1.3 to 7.8); smoking status (OR, 2.7, CI: 1.1 to 6.6) and SNAP score (OR, 1.04; CI: 1.0 to 1.1). CONCLUSION: Term babies admitted to NICUs may have significant health issues in childhood. Greater attention needs to be paid to long-term outcomes of term NICU graduates. Further study is warranted to address which NICU term survivors warrant secondary and/or tertiary-level neurodevelopmental follow-up.