386 Timing of previous cesarean section affects postpartum hemorrhage and maternal morbidity following sequential vaginal birth

Abstract

Women following vaginal birth after cesarean (VBAC) benefit from lower morbidities and reduced risks for future pregnancies, with the expense of higher rates of post partum complications including post-partum hemorrhage (PPH). This study aimed to investigate the association between the timing of previous cesarean section (CS) and the risk of post-partum adverse maternal outcomes following a subsequent successful VBAC. Retrospective case-control study of women following term vaginal delivery in a university-affiliated medical center between 2008-2018. Post-partum complications were compared between women who had their first VBAC and a control group of women following a vaginal delivery without a prior CS. Additional analysis was performed to evaluate the association between the timing of previous CS and the severity of post-partum adverse outcomes. 2879 women met inclusion criteria , 1455 had VBAC and 1424 had a vaginal delivery without a prior CS. Overall, significant post-partum complications, primarily PPH, were observed in the VBAC group compared to controls. Women with previous CS during the 2nd stage of labor presented a higher rate of PPH with a higher drop in hemoglobin levels when compared to women who underwent either emergent CS during 1st stage of labor or an elective CS (4.3±0.9g/dL vs. 2.8±1.1g/dL vs. 2.4±0.8g/dL, respectively, p=0.033). A concomitant increase in the need for blood transfusion (8.1% vs. 3.5% vs. 2.9%, respectively, p< 0.0001) and uterine atony rates (12.6% vs. 6.2% vs. 4.4%, respectively, p=0.009) was also noted. No significant differences were shown in duration of hospitalization, rate of uterine revision, vacuum assisted deliveries, postpartum urinary retention, endometritis, and obstetric and anal sphincter injuries (OASIS) (Table 1). VBAC is associated with an increased rate of post-partum complications, primarily PPH. The risk is significantly increased in women who were previously operated during the 2nd stage of labor (Figure 1). These data should be considered when counseling women for trial of labor after cesarean (TOLAC).View Large Image Figure ViewerDownload Hi-res image Download (PPT)