Impact of Gestational Weight Gain on Trial of Labor after Cesarean Success.

OBJECTIVE: Excessive gestational weight gain (GWG) has been associated with adverse pregnancy outcomes, including increased risk of cesarean delivery (CD). Data are limited on associations between GWG and outcomes in women undergoing trial of labor after cesarean (TOLAC). We aimed to investigate whether appropriate GWG impacts TOLAC outcomes. STUDY DESIGN: We performed a retrospective cohort study of women undergoing TOLAC at a single institution from May 2007 to April 2016. Women were divided into three groups based on GWG as compared with the Institute of Medicine recommendations. The primary outcome was successful vaginal birth after cesarean (VBAC). Secondary outcomes included various perinatal morbidity markers. RESULTS: A total of 614 women underwent TOLAC, of whom 444 (72.3%) had successful VBACs. When grouped by GWG in accordance with the Institute of Medicine guidelines, 149 (24.3%) women had GWG below guidelines, 224 (36.5%) met guidelines, and 241(39.3%) exceeded guidelines. There was no difference in the rate of VBAC success among the three groups. We also found no differences in secondary perinatal morbidity markers. CONCLUSION: We found no difference in TOLAC success rates with excess GWG. Providers should not consider excess GWG a risk factor for failed TOLAC, even in obese patients.

Impact of obesity class on trial of labor after cesarean success: does pre-pregnancy or at-delivery obesity status matter?

OBJECTIVE: To investigate whether pre-pregnancy versus at delivery obesity status impacts TOLAC success rates in a modern cohort. STUDY DESIGN: A retrospective cohort study of women undergoing TOLAC at a single institution from May 2007 to April 2016. Women were divided into four groups (not obese; class I, II, and III obesity) by pre-pregnancy and at delivery weight class. We investigated associations between obesity status at both time points and TOLAC success rates. RESULT: Six hundred and fourteen women underwent TOLAC; 444 (72.3%) had successful VBACs. We found no difference in rate of VBAC success across the four groups, both prior to pregnancy (p = 0.91) and at delivery (p = 0.75). We found no differences in secondary perinatal morbidity outcomes. CONCLUSION: We found no difference in TOLAC success rates stratified by obesity class. Properly counseling patients on TOLACs can lower rates of morbidity in women with high-risk conditions and comorbidities.

Validation of a Prediction Model for Vaginal Birth after Cesarean Delivery Reveals Unexpected Success in a Diverse American Population.

Objective To investigate the validity of a prediction model for success of vaginal birth after cesarean delivery (VBAC) in an ethnically diverse population. Methods We performed a retrospective cohort study of women admitted at a single academic institution for a trial of labor after cesarean from May 2007 to January 2015. Individual predicted success rates were calculated using the Maternal-Fetal Medicine Units Network prediction model. Participants were stratified into three probability-of-success groups: low (<35%), moderate (35-65%), and high (>65%). The actual versus predicted success rates were compared. Results In total, 568 women met inclusion criteria. Successful VBAC occurred in 402 (71%), compared with a predicted success rate of 66% (p = 0.016). Actual VBAC success rates were higher than predicted by the model in the low (57 vs. 29%; p < 0.001) and moderate (61 vs. 52%; p = 0.003) groups. In the high probability group, the observed and predicted VBAC rates were the same (79%). Conclusion When the predicted success rate was above 65%, the model was highly accurate. In contrast, for women with predicted success rates <35%, actual VBAC rates were nearly twofold higher in our population, suggesting that they should not be discouraged by a low prediction score.