Effect of birth order on neonatal morbidity and mortality among very low birthweight twins: a population based study
- 1Department of Neonatology, Kaplan Medical Center, Rehovot, and Hadassah Medical School, Hebrew University, Jerusalem Israel
- 2Department of Obstetrics and Gynecology, Kaplan Medical Center, Rehovot, and Hadassah Medical School, Hebrew University, Jerusalem Israel
- 3Women and Children’s Health Research Unit, Gertner Institute, Sheba Medical Center, Tel Hashomer, Israel
- 4Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
- Correspondence to:
Department of Neonatology, Kaplan Medical Center, Rehovot, Israel;
- Accepted 11 March 2003
Objective: To study the effect of birth order on the risk for respiratory distress syndrome (RDS), chronic lung disease (CLD), adverse neurological findings, and death in very low birthweight (VLBW; < 1500 g) twins.
Methods: A population based study of VLBW infants from the Israel National VLBW Infant Database. The sample included all complete sets of VLBW twin pairs admitted to all 28 neonatal intensive care units between 1995 and 1999. Outcome variables were compared by birth order and stratified by mode of delivery and gestational age, using General Estimating Equation models, with results expressed as odds ratio (OR) with 95% confidence interval (CI).
Results: Second twins were at increased risk for RDS (OR 1.51, 95% CI 1.29 to 1.76), CLD (OR 1.36, 95% CI 1.11 to 1.66), and death (OR 1.24, 95% CI 1.02 to 1.51) but not for adverse neurological findings (OR 1.20, 95% CI 0.91 to 1.60). Mode of delivery did not significantly influence outcome. The odds ratio for RDS in the second twin was inversely related to gestational age, and the increased risk for RDS and CLD was found in both vaginal and caesarean deliveries.
Conclusions: VLBW second twins are at increased risk for acute and chronic lung disease and neonatal mortality, irrespective of mode of delivery.