A seven-year retrospective cohort study on non-immune foetal hydrops from a single centre in an LMIC setting.

Objectives: To study the clinical profile, aetiology and outcomes of foetuses diagnosed with non-immune hydrops (NIHF) at a single centre between 2016 and 2023.

Methods: Pregnancies diagnosed with NIHF were studied retrospectively, using the antenatal records and neonatal electronic database.

Results: Ninety-two foetuses were diagnosed with NIHF including 8 sets of twins. Majority (64 %) were diagnosed in second trimester followed by 25 % in first trimester. One fourth (24 %, n=22) had IUFD (Intrauterine foetal demise) at diagnosis. Congenital anomalies were present in (57 %, 52) most common being cystic hygroma, (10/52) followed by foetal chylothorax and cardiac anomalies. Multiple anomalies were present in 15 % cases. Genetic evaluation, either chromosomal and/or DNA based test was done only in 62 % (57/92). More than one third (39 %, 22) had an abnormal karyotype, most common being 45, XO in 54 %, (12/22) followed by trisomy 21(9/22, 41 %). Twin-to-twin transfusion syndrome (TTTS) was seen in 75 % twins. Overall, most common etiologies were genetic, congenital anomalies, and unknown seen in 30 %, 26 %, and 23 % respectively. Majority of those with unknown aetiology were not/partially evaluated (13/21, 62 %). Recurrent NIHF was seen in 8 women. Two of them were diagnosed to have monogenic disorder while another one was carrier of a balanced chromosomal translocation.

Conclusions: Genetic aetiology was found in one third. The most common cause in twins was TTTS. One fifth had unknown aetiology, mostly due to lack of complete diagnostic work up.