Higher risk of hemorrhage and maternal morbidity in vaginal birth after second stage of labor C-section.

PURPOSE: This study evaluated the association between timing and indication for previous cesarean section (C-section) and its association with postpartum risks for adverse maternal outcomes, primarily postpartum hemorrhage (PPH) in vaginal birth after cesarean (VBAC).

METHODS

This retrospective case-control study examined women following term vaginal delivery in a university-affiliated medical center between 2008 and 2018. Postpartum complications were compared between women who had their first VBAC and a control group comprised of women who had vaginal delivery without prior C-section. Additional analysis was performed to evaluate the association between the timing of previous C-section and the severity of postpartum adverse outcomes.

RESULTS

Of the women meeting the inclusion criteria (n = 2879), 1,455 had VBAC and 1,424 were in the control group. Overall, significant postpartum complications, primarily PPH, were observed in the VBAC group compared to controls. Women who underwent C-section during second-stage of labor experienced higher PPH rates and increased drop in hemoglobin levels compared to women who underwent C-section during the first stage of labor or an elective C-Sect. (4.3 ± 0.9 g/dL vs. 2.8 ± 1.1 g/dL vs. 2.4 ± 0.8, p = 0.033). Concomitant increased need for blood transfusion (8.1% vs. 3.5% vs. 2.9%, respectively, p < 0.0001) and uterine atony (12.6% vs. 6.2% vs. 4.4%, respectively, p = 0.009) were also observed. No significant differences were demonstrated in other postpartum adverse effects evaluated.

CONCLUSION

VBAC is associated with higher rates of postpartum complications, primarily PPH. The risk is significantly increased in VBAC following a second stage cesarean section. This data should be taken into consideration in the management of laboring women after C-section.