(481) Risk Factors for Fetal Demise in Monochorionic Twins Complicated with Selective Fetal Growth Restriction

To investigate risk factors of single fetal demise in monochorionic (MC) twin pregnancies complicated with selective fetal growth restriction (sFGR).

Study Design: PubMed, Scopus, and Web of Science were searched systematically from inception until February 2022. Articles reporting on risk factors for fetal demise in sFGR were included. Presence of coexisting twin– twin transfusion syndrome (TTTS) was noted. The random-effect model was used to pool the mean differences or odds ratios (OR) and the corresponding 95% confidence intervals. Heterogeneity was assessed using the I² value.

Results:

Total of three studies encompassing 412 MC twin pregnancies with sFGR were included. Gestational age at diagnosis was significantly earlier in the fetal demise group (Mean difference: -0.9 weeks (95% CI -1.17- -0.62), I² 0.0%, p< 0.001). Presence of oligohydramnios in the smaller twin sac more than doubled the risk of fetal demise (OR: 2.6 (95% CI 1.45, 4.65), I² 0.0%, p=0.001). Umbilical artery (UA) Doppler deterioration increased the risk of demise by four times (OR: 4.08 (95% CI 2.30-7.25), I² 0.0%, p< 0.001), and development of superimposed TTTS doubled the risk of demise (OR: 2.3 (95% CI 1.12, 4.52), I² 0.0%, p=0.02). Although ductus venosus (DV) absent/reversed a-wave tripled the odds for demise (OR: 3.7 (95% CI 0.6-22.6), p=0.16), it was not statistically significant. Factors such as maternal age (p=0.04), primiparity (p=0.62), and invitro fertilization (IVF) pregnancy (p=0.53) were not significantly associated with increased risk of fetal demise.

Conclusion: Risk factors of single fetal demise in MC pregnancies complicated with sFGR included presence of oligohydramnios in the smaller twin sac, deterioration of UA Dopplers, and superimposed TTTS. These findings may provide guidance in the management of and counseling these pregnancies.