PERINATAL OUTCOMES IN PREGNANCIES IMMEDIATELY FOLLOWING STILLBIRTH - A MULTICENTER, PROSPECTIVE, OBSERVATIONAL STUDY.

Objective: To evaluate the outcomes of pregnancies immediately following stillbirth in relation to treatments prescribed.

Study design: A prospective, observational study was conducted in patients with a history of stillbirth (≥ 22 weeks) between 2014 and 2022 across four Italian University Hospitals. Outcomes were stratified based on the cause of previous fetal death (classified according with ReCoDe classification) and treatment (low dose aspirin (LDA), low molecular weight heparin (LMWH), both, progesterone or other drugs). The main outcome was adverse neonatal outcome, including perinatal death, stillbirth recurrence, intrauterine growth restriction, early preterm birth, Apgar <7 at 5 minutes and need for neonatal resuscitation. The secondary outcome was adverse maternal outcome, including postpartum hemorrhage, emergency cesarean delivery and operative vaginal delivery.

Results: Among 308 subsequent pregnancies, 46 (14.94%) had an adverse neonatal outcome, including 4 stillbirths. A total of 76 pregnancies (24.68%) experienced adverse maternal outcome, and 19 pregnancies (6.17%) had both. In individuals with previous placental vascular disorders, adverse neonatal outcomes were reduced by 75% when treated with LDA+ LMWH (OR 0.25, 95% CI 0.06-1.03, p=0.049). However, adverse maternal outcome was significantly higher in individuals who received LDA+LMWH without specific indications (OR 3.07, 95% CI 1.07-8.78, p=0.036).

Conclusions: LDA and LMWH should be prescribed only for previous placental vascular disorders to improve adverse neonatal outcome and avoid unnecessary maternal risk.