Comparison between fates of pregnancies with chorionic bumps with normal controls

Background: Chorionic bump (CB) represents an arterial hematoma in the chorionic plate early in pregnancy. It appears as focal rounded protrusion of the chorion (the early placenta) into the gestational sac (GS). The aim of our study is to explore the fate of such pregnancies in term of risks of miscarriage, preterm labour, fetal growth restriction (FGR) and intrauterine fetal demise (IUFD). Methods: This study is a retrospective case control study that entailed 1700 cases referred to a tertiary center at a gestational age window 6-10 weeks, between April 2018 and April 2024. CB was diagnosed if there was focal rounded protrusion of the chorion into the gestational sac that was separable from the yolk sac and the fetal pole. Results: 12 cases where diagnoses at the initial visit as having chorionic bump (i.e. 0.7% of cases). 8 cases of them continued their pregnancy normally without any complications till full term (i.e. 67% of CB cases give live birth). 4 cases of CB had been documented as failed pregnancy (miscarriage) on the follow up scan that was scheduled 3 weeks after the initial scan (i.e. 33% of CB cases had experienced spontaneous abortion). The incidence of failed pregnancy in the controls (that did not have CB) at the initial scan was 17%. Conclusions: Although the risk of spontaneous abortion in cases who had CB detected early in pregnancy is higher than normal controls (33% versus 17% respectively); most of such cases continues their pregnancy normally with 67% live birth rate.