90: The risk of perinatal death in twins stratified by gestational age: risk of expectant management

Abstract

other births were censored. Survival for Mono/Di vs. Di/Di twins, were compared by the log-rank test. Hazard ratios and 95% confidence intervals were estimated using a Cox proportional hazards model and adjusted for covariates that differed at baseline. RESULTS: Of the 754 twin pregnancies in the TPPD, 106 (14.1%) were excluded, 121 (16.0%) were Mono/Di twins and 527 (70%) were Di/Di twins. Stillbirths occurred in 4 (3.3%) Mono/Di [25-1/7, 260/7, 28-6/7, 34-1/7 weeks] and 3 (0.6%) Di/Di twin pairs [27-0/7, 30-0/7, 34-2/7 weeks]. Mono/Di twins had a higher risk of stillbirth compared with Di/Di twins, (log-rank P .007) (Figure A). After adjustment for maternal age at delivery, smoking, chronic hypertension and maternal DM, a Mono/Di twin pregnancy compared with a Di/Di twin pregnancy, is associated with 11.3 times higher risk of IUFD (HR 11.32, 1.15-111.59). CONCLUSION: Monochorionicity has a negative effect on the in-utero survival of twins, even among apparently normal monochorionicdiamniotic twins. In the absence of a clinical indication for delivery, these data do not support elective late preterm [34-36 weeks] delivery for prevention of intrauterine fetal demise in “apparently normal” Mono/Di twins.