Role of Antenatal IVIG in Improving Fetal Outcomes in Rh Isoimmunized Pregnancies: A Single-Centre Analysis

Rh isoimmunization remains a major cause of haemolytic disease of the fetus and newborn, particularly when fetal anaemia develops early in gestation. Antenatal intravenous immunoglobulin (IVIG) has been proposed to improve fetal outcomes, but evidence remains limited, especially from low- and middle-income settings.

This study was conducted at a tertiary care centre in India and included pregnant women with severe anti-D isoimmunization managed between 2023 and 2025. Inclusion criteria were pregnant women, with a previous pregnancy complicated by hydrops with perinatal death and/or requirement of intrauterine transfusion (IUT) before 24 weeks. They received antenatal IVIG (1 g/Kg/week from 13 to 14 weeks for 4-6 doses) and were compared with cases managed without IVIG. Outcomes analysed included presence of fetal hydrops, the requirement for IUT and the total number of IUTs, gestational age at first IUT, gestational age at delivery, and pregnancy outcome (live birth, stillbirth, or abortion) and neonatal outcomes.

Thirty-four pregnancies were included with17 managed with IVIG and 17 managed without IVIG based on the timing of referral. The incidence of fetal hydrops was significantly lower in the IVIG group (5.9% vs. 52.9%, p = 0.008), and preterm delivery occurred less frequently (70.5% vs. 100%, p = 0.04). The need for IUT, gestational age at first IUT, number of IUTs, gestational age at delivery, and birth weight were comparable between groups. Live birth rate and survival at discharge were higher in the IVIG group, though differences did not reach statistical significance. Infusion-related reactions occurred in 17.6% of IVIG-treated patients and were mild.

Antenatal IVIG was associated with reduced fetal hydrops and preterm delivery in severe Rh isoimmunized pregnancies. However, these findings should be interpreted with caution as improved outcomes may also reflect earlier referral, surveillance, and intervention.