Birth weight discordance and adverse perinatal outcomes

Objective: Our purpose was to examine the association between discordant growth and perinatal mortality and morbidity among twins with careful adjustment for maternal confounding factors. Study design: Two cohorts with and without chorionicity data were compared using generalized estimating modeling. Results: Our population-based dataset consisted of 12,656 individual twins from whom 4% (452/12,656) had >= 30% growth discordance. A subgroup of this population with chorionicity information had an incidence of 7.3% >= 30% growth discordance. In growth-discordant twins, perinatal mortality and morbidity were higher than concordant pairs (P < 0.01). Low Apgar score and perinatal mortality were more frequent in growth-discordant twins compared with growth-concordant ones (all P < 0.01). Conclusion: Birth weight discordance (BWD) places twins at increased risk of perinatal mortality. Growth discordance was also an independent risk factor for lower Apgar score of 5 min less than 5.