The outcome of monochorionic diamniotic twin gestations in the era of invasive fetal therapy: a prospective cohort study

Objective

The purpose of this study was to document pregnancy and neonatal outcome of monochorionic diamniotic twin pregnancies.

Study Design

This observational study describes a prospective series included in the first trimester in 2 centers of the Eurotwin2twin project.

Results

Of the 202 included twin pairs, 172 (85%) resulted in 2 survivors, 15 (7.5%) in 1 survivor, and 15 (7.5%) in no survivors. The mortality was 45 of 404 (11%), and 36 of 45 (80%) were fetal losses of 24 weeks or less, 5 of 45 (11%) between 24 weeks and birth, and 4 of 45 (9%) were neonatal deaths. Twin-to-twin transfusion syndrome (TTTS) occurred in 18 of 202 (9%). The mortality of TTTS was 20 of 36 (55%), which accounted for 20 of 45 (44%) of all losses. Severe discordant growth without TTTS occurred in 29 of 202 (14%). Its mortality was 5 of 58 (9%), which accounted for 5 of 45 (11%) of all losses. Major discordant congenital anomalies occurred in 12 of 202 (6%). Of the 178 pairs that continued after 24 weeks, 10 (6%) had severe hemoglobin differences at birth. After 32 weeks, the prospective risk of intrauterine demise was 2 in 161 pregnancies (1.2%; 95% confidence interval, 0.3-4.6).

Conclusion

Of the monochorionic twins recruited in the first trimester, 85% resulted in the survival of both twins, and 92.5% resulted in the survival of at least 1 twin. Most losses were at 24 weeks or less, and TTTS was the most important cause of death. After 32 weeks, the risk of intrauterine demise appears to be small.

Key words: growth, monochorionic twin pregnancy, outcome, twin transfusion syndrome