Project description:Importance:Whether the changing gestational age distribution in the United States since 2005 has affected perinatal mortality remains unknown. Objective:To examine changes in gestational age distribution and gestational age-specific perinatal mortality. Design, Setting, and Participants:This retrospective cohort study examined trends in US perinatal mortality by linking live birth and infant death data among more than 35 million singleton births from January 1, 2007, through December 31, 2015. Exposures:Year of birth and changes in gestational age distribution. Main Outcomes and Measures:Changes in the proportion of births at gestational ages 20 to 27, 28 to 31, 32 to 33, 34 to 36, 37 to 38, 39 to 40, 41, and 42 to 44 weeks; changes in perinatal mortality (stillbirth at ?20 weeks, and neonatal deaths at <28 days) rates; and contribution of gestational age changes to perinatal mortality. Trends were estimated from log-linear regression models adjusted for confounders. Results:Among the 34?236?577 singleton live births during the study period, the proportion of births at all gestational ages declined, except at 39 to 40 weeks, which increased (54.5% in 2007 to 60.2% in 2015). Overall perinatal mortality declined from 9.0 to 8.6 per 1000 births (P?<?.001). Stillbirths declined from 5.7 to 5.6 per 1000 births (P?<?.001), and neonatal mortality declined from 3.3 to 3.0 per 1000 births (P?<?.001). Although the proportion of births at gestational ages 34 to 36, 37 to 38, and 42 to 44 weeks declined, perinatal mortality rates at these gestational ages showed annual adjusted relative increases of 1.0% (95% CI, 0.6%-1.4%), 2.3% (95% CI, 1.9%-2.8%), and 4.2% (95% CI, 1.5%-7.0%), respectively. Neonatal mortality rates at gestational ages 34 to 36 and 37 to 38 weeks showed a relative adjusted annual increase of 0.9% (95% CI, 0.2%-1.6%) and 3.1% (95% CI, 2.1%-4.1%), respectively. Although the proportion of births at gestational age 39 to 40 weeks increased, perinatal mortality showed an annual relative adjusted decline of -1.3% (95% CI, -1.8% to -0.9%). The decline in neonatal mortality rate was largely attributable to changes in the gestational age distribution than to gestational age-specific mortality. Conclusions and Relevance:Although the proportion of births at gestational age 39 to 40 weeks increased, perinatal mortality at this gestational age declined. This finding may be owing to pregnancies delivered at 39 to 40 weeks that previously would have been unnecessarily delivered earlier, leaving fetuses at higher risk for mortality at other gestational ages.
Project description:OBJECTIVE:To evaluate the association between gestational weight gain and maternal and neonatal outcomes in a large, geographically diverse cohort. METHODS:Trained chart abstractors at 25 hospitals obtained maternal and neonatal data for all deliveries on randomly selected days over 3 years (2008-2011). Gestational weight gain was derived using weight at delivery minus prepregnancy or first-trimester weight and categorized as below, within, or above the Institute of Medicine (IOM) guidelines in this retrospective cohort study. Maternal (primary or repeat cesarean delivery, third- or fourth-degree lacerations, severe postpartum hemorrhage, hypertensive disease of pregnancy) and neonatal (preterm birth, shoulder dystocia, macrosomia, hypoglycemia) outcomes were compared among women in the gestational weight gain categories in unadjusted and adjusted analyses with odds ratios (ORs) and 95% CI reported. Covariates included age, race-ethnicity, tobacco use, insurance type, parity, prior cesarean delivery, pregestational diabetes, hypertension, and hospital type. RESULTS:Of the 29,861 women included, 51% and 21% had gestational weight gain above and below the guidelines, respectively. There was an association between gestational weight gain above the IOM guidelines and cesarean delivery in both nulliparous women (adjusted OR 1.44, 95% CI 1.31-1.59) and multiparous women (adjusted OR 1.26, 95% CI 1.13-1.41) and hypertensive diseases of pregnancy in nulliparous and multiparous women combined (adjusted OR 1.84, 95% CI 1.66-2.04). For the neonatal outcomes, gestational weight gain above the IOM guidelines was associated with shoulder dystocia (adjusted OR 1.74, 95% CI 1.41-2.14), macrosomia (adjusted OR 2.66, 95% CI 2.03-3.48), and neonatal hypoglycemia (adjusted OR 1.60, 95% CI 1.16-2.22). Gestational weight gain below the guidelines was associated with spontaneous (adjusted OR 1.50, 95% CI 1.31-1.73) and indicated (adjusted OR 1.34, 95% CI 1.12-1.60) preterm birth. CONCLUSION:In a large, diverse cohort with prospectively collected data, gestational weight gain below or above guidelines is associated with a variety of adverse pregnancy outcomes.
Project description:ImportanceTwin pregnancies account for 3% of live births but experience substantially more perinatal morbidity and mortality than singleton pregnancies. Optimizing the timing of birth is a key strategy in improving twin pregnancy outcomes. Current UK and US policies are based on observational studies of perinatal mortality and not on longer-term effects. The association of timing of birth with long-term childhood outcomes among twins is uncertain.ObjectiveTo identify the optimal gestation week for birth of twin infants by calculating the week of birth associated with the lowest risk of short-term and long-term adverse outcomes (perinatal mortality and special educational need [SEN] at school).Design, setting, and participantsThis population-based, data-linkage cohort study included 43 133 twin infants born at a gestational age of 34 weeks onward between January 1, 1980, and December 31, 2015, in Scotland. The data were analyzed from June 1, 2017, to March 1, 2019.ExposuresGestational age (in weeks) at the time of birth.Main outcomes and measuresThe primary outcomes were extended perinatal mortality and a record of SEN (?1 of intellectual disabilities, dyslexia, physical or motor impairment, language or speech disorder, autistic spectrum disorder, and social, emotional, or behavioral difficulties) at school (children aged 4-18 years). To infer the consequence of the gestational age at birth, clinical outcomes of twin infants born at each week of gestation from 34 weeks onward were compared with those of twin infants remaining in utero thereafter.ResultsOf the total 43 133 twin infants included in the study, 21 696 (50.3%) were females. Although maternity records were available for all infants, 9519 sex-discordant twin children were linked to their educational data, of whom 1069 (13.8%) had a record of SEN. Compared with twins remaining in utero (n?=?26?172), birth at any gestational age from 34 to 37 weeks was associated with increased odds of perinatal death (ie, adjusted odds ratio [AOR], 1.99; 95% CI, 1.53-2.69 at 36 weeks [n?=?8056]) and increased risk of SEN at school (AOR, 1.39; 95% CI, 1.11-1.74, for birth at 36 weeks compared with 37 weeks). In a competing risk analysis, the risks of stillbirth and neonatal death were balanced at 37 weeks (risk difference, 2.05; 95% CI, 0.8-3.3).Conclusions and relevanceThe findings of this study suggest that, in the absence of a medical complication, twins should not be routinely delivered before 37 completed weeks of gestation. These findings may help optimize shared decision-making around the timing of twin birth.
Project description:IntroductionThe pathophysiology behind the association between obesity and perinatal death is not fully understood but may be in part due to higher rates of pregnancy complications at earlier gestation amongst obese women. We aimed to quantify the proportion of perinatal deaths amongst obese and overweight women mediated by gestational age at stillbirth or live birth.MethodsThe study included all singleton births at ≥20 weeks' gestation in British Columbia, 2004-2017, and excluded pregnancy terminations. The proportion of the association between BMI and perinatal death mediated by gestational age at delivery (in weeks) was estimated using natural effect models, with adjustment for potential confounders. Sensitivity analyses for unmeasured confounding and women missing BMI were conducted.ResultsOf 392,820 included women, 20.6% were overweight and 12.8% obese. Women with higher BMI had a lower gestational age at delivery. Perinatal mortality was 0.5% (1834 pregnancies); and was elevated in overweight (adjusted odds ratio [AOR] = 1.22, 95% confidence interval [CI] 1.08-1.37) and obese women (AOR = 1.55, 95% CI 1.36-1.77). Mediation analysis showed that 63.1% of the association between obesity and perinatal death was mediated by gestational age at delivery (natural indirect effect AOR = 1.32, 95% CI 1.23-1.42, natural direct effect AOR = 1.18, 95% CI 1.05-1.32). Similar, but smaller effects were seen when comparing overweight women vs. women with a normal BMI. Estimated effects were not affected by adjustment for additional risk factors for perinatal death or sensitivity analyses for missing data.ConclusionObese pregnancies have a higher risk of perinatal death in part mediated by a lower gestational age at delivery.
Project description:BackgroundBabies with low birthweight (<2500 g) are at increased risk of early mortality. However, low birthweight includes babies born preterm and with fetal growth restriction, and not all these infants have a birthweight less than 2500 g. We estimated the neonatal and infant mortality associated with these two characteristics in low-income and middle-income countries.MethodsFor this pooled analysis, we searched all available studies and identified 20 cohorts (providing data for 2,015,019 livebirths) from Asia, Africa, and Latin America that recorded data for birthweight, gestational age, and vital statistics through 28 days of life. Study dates ranged from 1982 through to 2010. We calculated relative risks (RR) and risk differences (RD) for mortality associated with preterm birth (<32 weeks, 32 weeks to <34 weeks, 34 weeks to <37 weeks), small-for-gestational-age (SGA; babies with birthweight in the lowest third percentile and between the third and tenth percentile of a US reference population), and preterm and SGA combinations.FindingsPooled overall RRs for preterm were 6·82 (95% CI 3·56-13·07) for neonatal mortality and 2·50 (1·48-4·22) for post-neonatal mortality. Pooled RRs for babies who were SGA (with birthweight in the lowest tenth percentile of the reference population) were 1·83 (95% CI 1·34-2·50) for neonatal mortality and 1·90 (1·32-2·73) for post-neonatal mortality. The neonatal mortality risk of babies who were both preterm and SGA was higher than that of babies with either characteristic alone (15·42; 9·11-26·12).InterpretationMany babies in low-income and middle-income countries are SGA. Preterm birth affects a smaller number of neonates than does SGA, but is associated with a higher mortality risk. The mortality risks associated with both characteristics extend beyond the neonatal period. Differentiation of the burden and risk of babies born preterm and SGA rather than with low birthweight could guide prevention and management strategies to speed progress towards Millennium Development Goal 4--the reduction of child mortality.FundingBill & Melinda Gates Foundation.
Project description:This study used data on the total population to examine the longitudinal association between midlife income and mortality and late-life income and mortality in an aging Swedish cohort. We specifically examined the shape of the associations between income and mortality with focus on where in the income distribution that higher incomes began to provide diminishing returns. The study is based on a total Swedish population cohort between the ages of 50 and 60 years in 1990 (n=801,017) followed in registers for up to 19 years. We measured equivalent disposable household income in 1990 and 2005 and mortality between 2006 and 2009. Cox proportional hazard models with penalized splines (P-spline) enabled us to examine for non-linearity in the relationship between income and mortality. The results showed a clear non-linear association. The shape of the association between midlife (ages 50-60) income and mortality was curvilinear; returns diminished as income increased. The shape of the association between late-life (ages 65-75) income and mortality was also curvilinear; returns diminished as income increased. The association between late-life income and mortality remained after controlling for midlife income. In summary, the results indicated that a non-linear association between income and mortality is maintained into old age, in which higher incomes give diminishing returns.
Project description:To investigate the potential risk factors for small-for-gestational-age (SGA) and appropriate-for-gestational-age (AGA) late-term infants, 100 cases of single full-term SGA infants delivered in the Department of Obstetrics, The First Affiliated Hospital of Chongqing Medical University in 2017 were enrolled as the SGA group. A total of 100 healthy AGA who were born at the same time with the same gestational age were randomly included as the control group. The perinatal and postpartum adverse conditions of the two groups were recorded, and Apgar tests were performed on all newborns at 1 min (T1), 5 min (T2) and 10 min (T3) after birth. A follow-up survey was conducted in all patients at 6 and 12 months of age. At the second follow-up, the development quotient of the children was measured using the Gesell Developmental Schedule, and the perinatal risk factors of SGA were analyzed. The incidence of intrauterine distress, respiratory distress syndrome and infectious disease in the SGA group was significantly higher compared with that in the AGA group (P<0.05). The Apgar scores at T1, T2 and T3 were significantly lower in the SGA group compared with the AGA group (P<0.05). The Apgar score at T1 was lower compared with that at T2 in the SGA group (P<0.05), and the Apgar score at T2 was lower compared with that at T3 (P<0.05). The length of hospital stay in the SGA group was significantly longer compared with that in the AGA group (P<0.05). The development quotient at the 6 and 12th month in the SGA group was significantly lower compared with that in the AGA group (P<0.05). Logistic regression analysis showed that there was no correlation between SGA and maternal age, regardless of firstborn status, neonatal sex, mode of delivery and living environment. SGA was significantly associated with umbilical cord abnormalities, maternal pregnancy-induced hypertension, gestational diabetes, pregnancy infection and intrauterine distress (P<0.05). An abnormal umbilical cord, maternal pregnancy-induced hypertension, gestational diabetes, infection during pregnancy and intrauterine distress are all perinatal risk factors for SGA. Effective interventions are needed in clinical assessment to prevent the occurrence of SGA.
Project description:ObjectiveTo evaluate the association between in vitro fertilization (IVF) and ischemic placental disease (IPD), stratified by gestational age.DesignWe performed a secondary analysis of a retrospective cohort study of deliveries.SettingDeliveries were performed over 15 years at a single tertiary hospital.Patient(s)We included all parturients who had a live born infant or an intrauterine fetal demise (IUFD).Intervention(s)We compared pregnancies resulting from IVF cycles to non-IVF pregnancies.Main outcome measure(s)The primary outcomes were preterm and term IPD (preeclampsia, placental abruption, small-for-gestational age infant [SGA], or an intrauterine fetal demise [IUFD] due to placental insufficiency).Result(s)Of the 69,084 deliveries during the study period, 3,763 (5.4%) were conceived with IVF. The incidence of preterm delivery was 32.6% in IVF pregnancies and 10.8% in non-IVF pregnancies. Multiple gestations were more common in IVF pregnancies. Compared to non-IVF pregnancies, IVF pregnancies were more likely to develop both preterm and term IPD, even after adjustment for maternal age and parity. The risk of preterm IPD was 4 times higher (95% confidence interval, 3.7-4.4) in patients who underwent IVF compared with those who did not undergo IVF. Among parturients who delivered at ≥37 weeks of gestation, IVF pregnancies had 1.7 times the risk of term IPD (95% confidence interval, 1.6-1.9) compared with non-IVF pregnancies.Conclusion(s)IVF was strongly associated with preterm IPD. We found a similar, but attenuated, association between IVF and term IPD. The stronger association with preterm IPD suggests an association between IVF and placental insufficiency.
Project description:ObjectiveTo determine how gestational age relates to research-identified autism spectrum disorder (ASD-R) in the context of perinatal risk factors.Study designThis is a population-based cohort study using the 1994-2000 Olmsted County Birth Cohort. Children included were born and remained in Olmsted County after age 3 years. ASD-R status was determined from signs and symptoms abstracted from medical and educational records. Cox proportional hazards models were fit to identify associations between perinatal characteristics and ASD-R.ResultsThe incidence of preterm birth (<37 weeks' gestation) was 8.6% among 7876 children. The cumulative incidence of ASD-R was 3.8% (95% CI 3.3-4.2) at 21 years of age. Compared with children born at full term, the risk of ASD-R appeared to be increased for children born preterm with unadjusted hazard ratios (HRs) of 2.62 (95% CI 0.65-10.57), 1.68 (95% CI 0.54-5.29), and 1.60 (95% CI 1.06-2.40) for children born extremely preterm, very preterm, and moderate-to-late preterm, respectively. In a multivariable model adjusted for perinatal characteristics, the associations were attenuated with adjusted HRs of 1.75 (95% CI 0.41-7.40), 1.24 (95% CI 0.38-4.01), and 1.42 (95% CI 0.93-2.15), for children born extremely preterm, very preterm, and moderate-to-late preterm, respectively. Among children with maternal history available (N = 6851), maternal psychiatric disorder was associated with ASD-R (adjusted HR 1.73, 95% CI 1.24-2.42).ConclusionsThe increased risk of ASD-R among children born preterm relative to children born full term was attenuated by infant and maternal characteristics.
Project description:Pregnancy increases the requirements of certain nutrients, such as vitamins, to provide nutrition for the newborn. The aim was to analyze the association between dietary intake of vitamins during pregnancy and risk of having a small for gestational age (SGA) newborn. A matched case-control study was conducted (518 cases and 518 controls of pregnant women) in Spain. Dietary vitamin intake during pregnancy was assessed using a validated food frequency questionnaire, categorized into quintiles. Odds ratios (ORs) and their 95% confidence intervals (CI) were estimated with conditional regression logistic models. A protective association was observed between maternal dietary intake of vitamins A and D and SGA. For vitamin B3 and B6, the observed protective effect was maintained after adjusting for potential confounding factors. For vitamin B9, we found only an effect in quintiles 3 and 4 (OR = 0.64; 95% CI, 0.41-1.00; OR = 0.58; 95% CI, 0.37-0.91). Protective effect for vitamin B12 was observed in 4th and 5th quintiles (OR = 0.61; 95% CI, 0.39-0.95; OR = 0.68; 95% CI, 0.43-1.04). No associations were detected between dietary intake of vitamins B2, E and C intake and SGA. Our results suggest a positive association between dietary vitamin intake during pregnancy and the weight of the newborn, although more studies are necessary and there could be a ceiling effect for higher intakes of some vitamins cannot be discarded.