RESUMEN
We aimed to determine the effect of delivery mode on postnatal platelet count dynamics in neonates born to mothers with immune thrombocytopenia (ITP). This single-center, retrospective study included 41 mothers with ITP and their 65 infants born by vaginal delivery (VD, n = 30) and cesarean section (CS, n = 35) between January 1997 and March 2022. The median difference in platelet counts from day 0 to day 2 (ΔPlt [D 0-2]) was significantly lower in the VD group (- 39 × 109/L, interquartile range [IQR]: - 47 to - 24 × 109/L) than the CS group (15 × 109/L, IQR: - 6.5 to 33 × 109/L) (p < 0.001). The median ΔPlt (D 0-5) was significantly lower in the VD group (- 55 × 109/L, IQR: - 85 to - 31 × 109/L) than the CS group (33 × 109/L, IQR: 1-69 × 109/L) (p < 0.001). Multivariate analysis also showed a significant association of delivery mode with ΔPlt (D 0-2) and ΔPlt (D 0-5) (both p < 0.001). VD neonates with platelet counts ≥ 100 × 109/L at birth were significantly more likely than CS neonates to develop thrombocytopenia < 100 × 109/L at nadir (1/26 vs. 6/25) (p = 0.0496). Our findings indicate that mode of delivery is a useful predictor of postnatal platelet count dynamics in neonates born to mothers with ITP.