Should discordancy be cause for delivery of preterm twins?

OBJECTIVE: There are few guidelines for the management of discordant twins. The purpose of this study was to compare outcomes of preterm discordant twins with concordant twins. We hypothesized that growth discordancy in itself plays a minor role in perinatal morbidity/mortality and should not prompt preterm delivery. STUDY DESIGN: All discordant twins denned as >20% by birthwetght delivered between 1/1/88 and 12/31/95 at our institution were reviewed. Same sex twins, gestational age >24 and <37 weeks, and birthweight >500 grams were included. Maternal data was analyzed for demographics and risk factors for growth restriction. Neonatal records were reviewed for gestational age, birthweight and order, apgars, sex, and mode of delivery. Major and minor outcome variables limited to the initial hospitalization included death, respiratory distress syndrome, intraventricular hemorrhage, patent ductus arteriosus, necrotizing enterocolitis, bronchopulmonary dysplasia, sepsis, hyperbilirubinemia, anemia, apnea/bradycardia, hypocalcemia, hypoglycemia, and length of hospital stay. Chi Square analysis was performed. RESULTS: 119 sets of twins were evaluated. 42 sets were discordant with no stillbirths. Outcome of discordant and gestationatly controlled concordant sets was similar although discordant sets had longer hospital stays (p = 0.013). Within the 42 discordant sets, smaller twins had a longer length of stay (p = 0.034), but did not differ from the larger twin in any other major or minor outcome. However, morbid outcomes among all individual infants were highly associated (p < 0.001) with gestational age <32 weeks, birthweight <2000 grams and presence of growth restriction, CONCLUSIONS: Preterm discordant twin sets do not demonstrate increased morbidity/mortality over concordant sets when controlled for gestational age. Delivery management of discordant twins should be based on the individual fetus in terms of their gestational age and weight achieved and the presence of growth restriction but not on the presence of discordancy alone.