Long-term morbidity of triplets according to their birth order; A population- based cohort study

Abstract

The association between birth order and adverse perinatal outcome has been studies vastly in twin pregnancies. However, little is known regarding differences in long-term morbidity within triplets according to birth order. Hence, we opted to assess differences in long-term morbidities of triplets by their birth order. In a population-based retrospective cohort study, the incidence of long-term morbidity was compared between the triplet's siblings according to their birth order. Deliveries occurred between the years 1991 and 2021 in a tertiary medical center. The study groups were followed until 18 years of age for cardiovascular, respiratory, neurological and infectious- related morbidities. Kaplan-Meier survival curves were used to compare cumulative morbidity and Cox proportional hazards models were performed to control for confounders. The study included 117 triplet deliveries. No significant differences in cardiovascular, respiratory, neurological and infectious, morbidities were noted between the first, second and third sibling (Table). Likewise, no significant differences in cumulative incidence of long-term pediatric morbidities were noted between the siblings, using Kaplan-Meier survival analyses (Figure). In Cox proportional hazards models, controlling for weight and gender, birth order in triplet pregnancy did not exhibit an association with long-term morbidities of the offspring. Despite the known association between birth order in twins and adverse perinatal outcome, birth order in triplets does not seem to have an impact on the long-term morbidity of the offspring.View Large Image Figure ViewerDownload Hi-res image Download (PPT)