Maternal and fetal outcomes after recurrent pregnancy loss in an exclusively black cohort

Recurrent pregnancy loss (RPL) affects 2-5 % of patients trying to build their families. RPL is frequently unexplained, though hematologic, immune, uterine, or genetic factors are associated with both RPL. These same risk factors for RPL are associated with poor obstetric outcomes. However, pregnancy outcomes after RPL are poorly studied. While Black race is a known risk factor for both miscarriage and hypertensive disorders of pregnancy (HDP), it is unknown if RPL increases risk of developing HDP or other pregnancy complications in Black pregnant people. The objective of this study is to assess the maternal and fetal outcomes in low-income Black patients delivering after a history of RPL.

We performed a retrospective cohort study in exclusively low-income Black females with a delivery > 20 weeks identified based on gestational age at delivery at a single community hospital between January 1, 2018 and December 30, 2022. RPL was defined as 2 or more pregnancy losses prior to the examined pregnancy. RPL patients were compared to controls with no more than one prior miscarriage. Obstetric and neonatal outcomes were compared using a multivariate regression analysis controlling for age, chronic hypertension, aspirin use, smoking status, BMI, and diagnosis of HDP in a prior pregnancy.

2598 patients met inclusion criteria (248 patients with RPL and 2344 controls) 9.6 % of patients had a history of RPL. Overall, 14.6 % of patients were diagnosed with any HDP. Patients with a history of RPL were significantly more likely to develop any HDP in the examined pregnancy (aOR 1.57 CI[1.11, 2.22]). Additionally, patients with RPL were more likely to be diagnosed with preeclampsia with severe features (aOR1.77 CI [1.05, 2.98]) and gestational hypertension (aOR 1.75 CI [1.11, 2.275]. Patients with RPL were also more likely to deliver preterm (aOR 1.58 CI [1.32, 2.22] and deliver low birthweight infants (OR 1.44 [1.05,1.98]). There were no differences in 1- and 5-minute APGAR scores.

The rate of RPL was high in this cohort, at 9.6 %. Low-income Black patients with RPL were at increased risk of HDP, specifically gestational hypertension and preeclampsia with severe features, as well as preterm delivery compared to low-income Black patients without RPL. Future studies are needed to assess the underlying pathophysiology of recurrent pregnancy loss and HDP to identify opportunities for risk reduction for this high risk and understudied population.