P-474 Association between subchorionic hematoma’s size and miscarriage rate in IVF/ICSI patients

Abstract Study question What is the risk factor for miscarriage in patients undergoing IVF/ICSI with subchorionic hematoma(SCH) in the first trimester? Summary answer The size of SCH is a risk factor for miscarriage in patients undergoing IVF/ICSI. Miscarriage rate increases as the size of SCH grows. What is known already SCH is a frequently observed pathology during routine ultrasound examinations in early pregnancy. Its clinical significance has been unclear. Some studies believed that SCH found in first trimester was not correlated with adverse pregnancy outcome; Other studies believed that SCH in early pregnancy can cause a significant increase in the incidence of late pregnancy complications, such as preterm labor, preeclampsia, and postpartum hemorrhage. Besides, what are the risk factors for miscarriage in pregnant women with SCH? Answers to these questions are urgently needed. Study design, size, duration Retrospective cohort study with 646 patients undergoing IVF/ICSI at a tertiary care university hospital, between February 2017 and November 2020. Participants/materials, setting, methods All patients who underwent IVF/ICSI from February 2017 to November 2020, achieved pregnancy and underwent transvaginal ultrasound at our center during first trimester were included. Risk factors for miscarriage in patients with SCH were explored. Miscarriage rates in patients with different SCH sizes which was expressed as its' ratio to the area of the gestational sac were compared. Main results and the role of chance Patients with SCH who had more embryos transferred (P=0.01), earlier detection of IUH (P=0.003), a smaller GS area (P=0.03) was prone to miscarry. The size of SCH is a risk factor for miscarriage (P = 0.016). Miscarriage rate increased with increasing size of SCH (P for trend: 0.003). Limitations, reasons for caution The main limitation of this study is its retrospective nature and relatively small sample size. Wider implications of the findings Extra clinical attention needs to be paid to the miscarriage risk of in IVF/ICSI patients with large SCH. There is urgent need for future research on SCH affecting pregnancy outcome and the underlying pathophysiological mechanisms. Trial registration number Not applicable