Dataset Information

Association of Gestational Age at Birth With Risk of Perinatal Mortality and Special Educational Need Among Twins.

ABSTRACT:

Importance

Twin 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.

Objective

To 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 participants

This 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.

Exposures

Gestational age (in weeks) at the time of birth.

Main outcomes and measures

The 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.

Results

Of 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 relevance

The 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.

SUBMITTER: Murray S

PROVIDER: S-EPMC7063542 | biostudies-literature | 2020 May

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Association of Gestational Age at Birth With Risk of Perinatal Mortality and Special Educational Need Among Twins.

Murray Sarah S MacKay Daniel D Stock Sarah S Pell Jill J Norman Jane J

JAMA pediatrics 20200501 5

<h4>Importance</h4>Twin 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.<h4>Objective</h4>To identify the optima ...[more]

PMID: 32150231

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Project description:ImportanceThe association between household income and perinatal health outcomes has been understudied. Examining disparities in perinatal mortality within strata of gestational age and before and after adjusting for birth weight centile can reveal how the income gradient is associated with gestational age, birth weight, and perinatal mortality.ObjectivesTo investigate the association between household income and perinatal mortality, separately by gestational age strata and time of death, and the potential role of birth weight centile in mediating this association.Design, setting, and participantsThis cross-sectional study used individually linked data of all registered births in the Netherlands with household-level income tax records. Singletons born between January 1, 2004, and December 31, 2016, at 24 weeks to 41 weeks 6 days of gestation with complete information on birth outcomes and maternal characteristics were studied. Data analysis was performed from March 1, 2018, to August 30, 2021.ExposuresHousehold income rank (adjusted for household size).Main outcomes and measuresPerinatal mortality, stillbirth (at ≥24 weeks of gestation), and early neonatal mortality (at ≤7 days after birth). Disparities were expressed as bottom-to-top ratios of projected mortality among newborns with the poorest 1% of households vs those with the richest 1% of households. Generalized additive models stratified by gestational age categories, adjusted for potential confounding by maternal age at birth, maternal ethnicity, parity, sex, and year of birth, were used. Birth weight centile was included as a potential mediator.ResultsAmong 2 036 431 singletons in this study (1 043 999 [51.3%] males; 1 496 579 [73.5%] with mother of Dutch ethnicity), 121 010 (5.9%) were born before 37 weeks of gestation, and 8720 (4.3 deaths per 1000) died during the perinatal period. Higher household income was positively associated with higher rates of perinatal survival, with an unadjusted bottom-to-top ratio of 2.18 (95% CI, 1.87-2.56). The bottom-to-top ratio decreased to 1.30 (95% CI, 1.22-1.39) after adjustment for potential confounding factors and inclusion of birth weight centile as a possible mediator. The fully adjusted ratios were lower for stillbirths (1.27; 95% CI, 1.20-1.36) than for early neonatal deaths (1.35; 95% CI, 1.14-1.66). Inequalities in perinatal mortality were found for newborns at greater than 26 weeks of gestation but not between 24 and 26 weeks of gestation (fully adjusted bottom-to-top ratio, 0.89; 95% CI, 0.77-1.04).Conclusions and relevanceThe results of this large nationally representative cross-sectional study suggest that a large part of the increased risk of perinatal mortality among low-income women is mediated via a lower birth weight centile. The absence of disparities at very low gestational ages suggests that income-related risk factors for perinatal mortality are less prominent at very low gestational ages. Further research should aim to understand which factors associated with preterm birth and lower birth weight can reduce inequalities in perinatal mortality.

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:ImportancePreterm and postterm births are associated with adverse neuropsychiatric outcomes. However, it remains unclear whether variation of gestational age within the 37- to 42-week range of term deliveries is associated with neurodevelopment.ObjectiveTo investigate the association of gestational age at birth (GAB) with structural brain morphometry in children aged 10 years.Design, setting, and participantsThis population-based cohort study included pregnant women living in Rotterdam, the Netherlands, with an expected delivery date between April 1, 2002, and January 31, 2006. The study evaluated 3079 singleton children with GAB ranging from 26.3 to 43.3 weeks and structural neuroimaging at 10 years of age from the Generation R Study, a longitudinal, population-based prospective birth cohort from early pregnancy onward in Rotterdam. Data analysis was performed from March 1, 2019, to February 28, 2020, and at the time of the revision based on reviewer suggestions.ExposuresThe GAB was calculated based on ultrasonographic assessment of crown-rump length (<12 weeks 5 days) or biparietal diameter (≥12 weeks 5 days) in dedicated research centers.Main outcomes and measuresBrain structure, including global and regional brain volumes and surface-based cortical measures (thickness, surface area, and gyrification), was quantified by magnetic resonance imaging.ResultsIn the 3079 children (1546 [50.2%] female) evaluated at 10 years of age, GAB was linearly associated with global and regional brain volumes. Longer gestational duration was associated with larger brain volumes; for example, every 1-week-longer gestational duration corresponded to an additional 4.5 cm3/wk (95% CI, 2.7-6.3 cm3/wk) larger total brain volume. These associations persisted when the sample was restricted to children born at term (GAB of 37-42 weeks: 4.8 cm3/wk; 95% CI, 1.8-7.7 cm3/wk). No evidence of nonlinear associations between GA and brain morphometry was observed.Conclusions and relevanceIn this cohort study, gestational duration was linearly associated with brain morphometry during childhood, including within the window of term delivery. These findings may have marked clinical importance, particularly given the prevalence of elective cesarean deliveries.

Project description:BackgroundBreakthroughs in the treatment of preterm birth approximately 40 years ago have enabled a generation of preterm survivors to now reach mid-adulthood. Understanding their health sequelae is essential for guiding their long-term care. We did a study to examine preterm birth in relation to mortality into mid-adulthood.MethodsA national cohort study was done of all 4 296 814 singleton livebirths in Sweden between 1973 and 2015, who were followed up for mortality through Dec 31, 2017 (maximum age 45 years). Cox regression was used to examine gestational age at birth in relation to all-cause and cause-specific mortality, and cosibling analyses assessed for potential confounding by shared familial (genetic or environmental) factors.FindingsIn 103·5 million person-years of follow-up, 43 916 (1·0%) deaths were reported. Gestational age at birth was inversely associated with mortality from infancy to mid-adulthood. Relative to full-term birth (39-41 weeks), the adjusted hazard ratios for mortality associated with gestational age at birth were: 66·14 (95% CI 63·09-69·34) for extremely preterm (22-27 weeks), 8·67 (8·32-9·03) for very preterm (28-33 weeks), 2·61 (2·52-2·71) for late preterm (34-36 weeks), and 1·34 (1·30-1·37) for early term (37-38 weeks), from birth to age 45 years; and 2·04 (0·92-4·55) for extremely preterm, 1·48 (1·17-1·87) for very preterm, 1·22 (1·07-1·39) for late preterm, and 1·16 (1·08-1·25) for early term, at ages 30-45 years. Preterm birth accounted for more deaths among males than females (additive interaction p<0·001). Multiple underlying causes were identified, including congenital anomalies; respiratory, endocrine, cardiovascular, and neurological diseases; cancer; and external causes. Cosibling analyses suggested that the observed associations were not due to shared genetic or environmental factors in families.InterpretationPreterm and early term birth should be recognised as chronic conditions that require long-term follow-up for adverse health sequelae in adulthood.FundingNational Heart, Lung, and Blood Institute at the National Institutes of Health.

Dataset Information

Association of Gestational Age at Birth With Risk of Perinatal Mortality and Special Educational Need Among Twins.

Importance

Objective

Design, setting, and participants

Exposures

Main outcomes and measures

Results

Conclusions and relevance

Publications

Association of Gestational Age at Birth With Risk of Perinatal Mortality and Special Educational Need Among Twins.

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