Postpartum hemorrhage among twin pregnancies - Medically assisted versus spontaneously conceived.

INTRODUCTION: In singleton pregnancies, an increased risk of Postpartum hemorrhage (PPH) have been linked with assisted reproductive technology (ART) and abnormal placentation. It is unknown wheather such association exists in twin pregnancies conceived by Medically assisted reproduction (MAR). The aim of the current study was to compare maternal blood loss among twin pregnancies conceived by different types of MAR treatments to spontaneously conceived twins and to identify the cycle characteristics if an association exits. METHODS: Retrospective study conducted on data collected between 2011 and 2020. The study cohort included all twin pregnancies conceived by MAR and born at our institution. Controls were spontaneously conceived twins matched for maternal age on a 1:2 (study: controls) ratio. RESULTS: Overall 113 MAR twin births categorized into three groups; 25 ovulation induction, 59 fresh ART, 29 frozen-thawed ART cycles, and 226 controls were included. The incidence of PPH was higher among MAR twin pregnancies (5.3%) compared to the controls (4%). The highest incidence was observed among women in the frozen-thawed group (13.8%) which differed significantly compared with the controls (p = 0.024). A significant difference was also observed in the mean decrease of postpartum hemoglobin levels between these two groups (2.13 g/dL versus 1.3 g/dL respectively, p = 0.002). Blood transfusion was nearly 2.5 times more common in the frozen-thawed group (3.4%) compared to the control group (1.3%). DISCUSSION: The present study demonstrates that frozen embryo transfer (FET) ART-conceived twin pregnancies are associated with a markedly increased rate of PPH compared to spontaneously conceived twins.