Evidence that children born at early term (37-38 6/7 weeks) are at increased risk for diabetes and obesity-related disorders.

BACKGROUND: Prematurity is known to be associated with high rates of endocrine and metabolic complications in the offspring. Offspring born early term (37-38 6/7 weeks' gestation) were also shown to exhibit long-term morbidity resembling that of late preterm, in several health categories.

OBJECTIVE: We aimed to determine whether early term delivery impacts on the long-term endocrine and metabolic health of the offspring.

STUDY DESIGN: A population-based cohort analysis was performed, including all term singleton deliveries occurring from 1991 through 2013 at a single regional tertiary medical center. Congenital malformations and multiple pregnancies were excluded. Gestational age upon delivery was subdivided into early term deliveries and deliveries occurring at full term and later (≥39 weeks' gestation, comparison group). Endocrine and metabolic morbidity (including diabetes, obesity, hypoglycemia, hyperlipidemia, and hypothyroidism) of the offspring, up to the age of 18 years, was evaluated according to hospitalization files. Kaplan-Meier survival curves were used to compare cumulative morbidity incidence. A Weibull parametric survival model was used to control for time to event, siblings, and other confounders.

RESULTS: During the study period 225,260 term deliveries met the inclusion criteria. Of them, 24% (n = 54,073) occurred at early term. Endocrine and metabolic morbidity was significantly more common in the early term group (0.51% vs 0.41%, P = .003). Specifically, overweight and obesity were more common among the early term group (P = .002). Differences were more prominent among children >5 years, who exhibited higher rates of type 1 diabetes mellitus, as well as obesity, when born at early term (P < .05). The survival curves demonstrated higher cumulative incidence of total endocrine and metabolic morbidity in the early term group. Using the Weibull parametric survival model, while controlling for siblings, maternal diabetes, hypertension, labor induction, and Apgar score, early term delivery exhibited an independent association with long-term childhood endocrine and metabolic morbidity of the offspring (adjusted hazard ratio, 1.17; 95% confidence interval, 1.01-1.34) and more so for age >5 years (adjusted hazard ratio, 1.30; 95% confidence interval, 1.08-1.56).

CONCLUSION: Deliveries occurring at early term are associated with higher rates of long-term pediatric endocrine and metabolic morbidity of the offspring as compared with deliveries occurring at a later gestational age. This association may be due to absence of full maturity of the hormonal axis in early term neonates or, alternatively, suggest an underlying fetal endocrine dysfunction as the initial mechanism responsible for spontaneous early term delivery.