Evaluation of Non-Immune Fetal Hydrops in Resource Poor Country: Challenges Faced in Ascertaining the Etiology

Analyze the proportion of cases of non-immune hydrops fetalis (NIHF), where etiology could be ascertained using limited tests and determine outcome.

A retrospective observational study of prenatally diagnosed NIHF at a tertiary referral center in India over 10 years from 2014 to 2023 using the data retrieved from case files, ultrasound and investigation reports.

Included 184 NIHF events in 166 patients with an estimated prevalence of 0.11% (184/160,156 deliveries). 42.5% of women were primigravida and 30 cases were in 12 patients presenting with recurrent hydrops. Etiology could be ascertained in 76/154 (49.35%) total new cases of hydrops presenting for the first time and in 9/12 (75%) total patients with recurrent NIHF. The most common causes among first time NIHF were structural anomalies and aneuploidies, while inborn errors of metabolism (IEM) were the most common in recurrent cases. The diagnostic yield of ultrasound alone was 30.7% (51/166 patients), which improved with addition of tests to 45.78% (76/166) with cytogenetic and 53.6% (89/166) with sequencing studies. The overall survival beyond 28 days of postnatal life was 9.2% (17/184 events), with the rest ending in MTP/spontaneous abortion 47.8% (88/184), stillbirth 24.5% (45/184), early neonatal death 17.4% (32/184) and late neonatal death 1.1% (2/184). Treatable causes included fetal arrhythmias, some structural anomalies and certain IEMs amenable to early postnatal dietary intervention.

Although overall survival in NIHF is poor, the aim of diagnostic workup should be to find a treatable cause. Even with limited resources, etiology can still be deduced in more than half of the cases. Management decisions can often be made based on history and ultrasonography while restricting the expensive genetic tests to unexplained or recurrent cases.