Prediction of intrauterine death and severe preterm delivery in twin pregnancies discordant for major fetal abnormality.

Objective: To investigate predictors of spontaneous fetal death and preterm delivery in twin pregnancies with one fetus affected by a major structural malformation.

Study Design: Retrospective study (1999-2012) conducted at a tertiary teaching hospital involving 51 twin pregnancies (dichorionic=31, monochorionic diamniotic=15, monochorionic monoamniotic=4, not established=1) with a major fetal abnormality, enrolled before 26 weeks and managed expectantly.

Primary Outcomes: spontaneous fetal death, and/or delivery before 32 weeks. Prediction was examined with stepwise logistic regression analysis, and independent variables included: maternal age, gestational age at diagnosis, chorionicity, fetal gender, number and type of fetal abnormalities. Significance level was set at 0.15.

Results: Fetal abnormalities were diagnosed at a mean gestation of 21.5±3.7 weeks: cardiac abnormalities were observed in 31.4% of abnormal fetuses, abdominal wall defects in 29.4%, central nervous system 21.5%, spine 17.6%, effusions 17.6%, noncardiac thoracic abnormalities 15.7%, genital and urinary system 13.7%, limbs and soft tissue 3.9%, intestinal 1.9% and facial defects 1.9%. Fetal death occurred in 15 (29.4%) abnormal fetuses and was significantly correlated with the number of fetal malformations (p=0.02, OR=2.54, 95% CI=1.14-5.62), presence of effusion/hydrops (p=0.06, OR=4.7, 95% CI=0.95-24) and monochorionic placenta (p=0.11, OR=2.8, 95% CI=0.78-9.8). Normal co-twin fetal death occurred in four cases (7.8%) and was related to monochorionic pregnancies (p=0.14, OR=5.8, 95% CI=0.56-61). Delivery before 32 weeks was observed in 14 (27.5%) pregnancies and was related to presence of effusion/hydrops (p=0.04, OR=5.5, 95% CI=1.07-28).

Conclusion: Spontaneous fetal death and/or delivery before 32 weeks in twin pregnancies with one fetus affected by a major structural malformation are related to the number of abnormalities diagnosed and presence of fetal effusion or hydrops.