Comparison of indomethacin and nifedipine regarding ductus arteriosus Doppler findings after laser therapy for monochorionic diamniotic twin-to-twin transfusion syndrome: A retrospective cohort study.

BACKGROUND

Indomethacin is administered to reduce preterm labor after fetoscopic laser photocoagulation (FLP) of placental anastomoses.

OBJECTIVE

To compare ductus arteriosus (DA) Doppler findings in monochorionic diamniotic twin pregnancies complicated by twin-to-twin transfusion syndrome following FLP between cases treated with indomethacin and those treated with nifedipine.

MATERIALS AND

METHODS

In this retrospective cohort study, data of 86 pregnant women aged 17-41 yr who underwent FLP in Shariati hospital, Tehran, Iran from October 2024-November 2025 were extracted from medical records and then followed up. In the study, based on pulse rate, the cases were placed in one of 2 groups: nifedipine (pulse rate < 100) and indomethacin (pulse rate > 100) for 48 hr. In cases receiving indomethacin, 6 cases developed DA constriction. A comprehensive fetal echocardiography was performed to assess the status of the DA before and after FLP.

RESULTS

Peak systolic velocity was higher in both donor (145.7 ± 32.2, p = 0.012) and recipient twins (147.2 ± 23.6, p = 0.010) in the constricted group compared with the non-constricted groups. In recipient twins, end-diastolic velocity mean was also significantly increased (32.0 in the constricted, 19.9 in the indomethacin, and 18.7 in the nifedipine group, p = 0.012), while pulsatility index mean was significantly lower in the constricted group (1.8, 2.6, 2.5, respectively, p = 0.010).

CONCLUSION

DA constriction is associated with significant changes in blood flow indices, a higher incidence of right ventricular dysfunction, and a greater prevalence of valvular regurgitation. In this study, fetal DA constriction resolved during the short-term follow-up period.