Stillbirth Associated With Birth Weight Discordance in Twin Gestations.

OBJECTIVE

Stillbirth is an important adverse outcome associated with twin pregnancy. We aimed at investigating the association between birth weight discordance (BWD) and stillbirth.

METHODS

We carried out two retrospective cohort studies including twin births registered in British Columbia from 2000 to 2010 and a subsample with chorionicity information. Generalized estimating equation models for binary outcome were used to account for the correlation in twin outcomes.

RESULTS

The province-based cohort included 12 814 twins. In the nonstratified analysis, an increase in BWD was found to be associated with an increased risk of stillbirth even after accounting for potential confounding factors (13.69; 95% CI 7.32-25.62). In the analysis stratified by fetal growth, the stillbirth rate was determined to be higher in subjects with a BWD ≥30% compared with the reference group. BWD-related stillbirth was dependent on fetal growth, parity, GA, twin size, sex discordance, and chorionicity. A subgroup analysis showed that odds of stillbirth were 5.21 times higher in twins with BWD ≥30% than the reference category (95% CI 2.17-12.47) after adjustment for chorionicity.

CONCLUSIONS

In screening twin pregnancies, special attention should be paid to fetal growth, parity, GA, twin size, and chorionicity. Sex discordance is a good proxy for chorionicity when these data are not available.