Skip to main content
SMFM 2024 Pregnancy Meeting Main banner
Final Program


Icon Legend
This session is not in your schedule.
This session is in your schedule. Click again to remove it.
Presentation Icons
Additional registration fee required
Additional registration fee required
Faculty have requested this content not be shared on social media
Faculty have requested this content not be shared on social media
CME Credit Offered
CME Credit Offered
Poster Icons
Foundation Awardee
Foundation Awardee
No Social Media
No Social Media
Back
Q&A

Operative Obstetrics

Poster Session 2

(434) Evaluating the Predictive Value of Risk Factors for Fetal Acidosis at Scheduled Cesarean Deliveries

Tuesday, February 13, 2024
3:30 PM – 5:00 PM  
Location: Prince George's Exhibit Hall CDE, Lower Atrium Level
Objective: This study evaluates the relative impacts of maternal and surgical risk factors, both separately and together, on the risk of fetal acidosis at scheduled cesarean delivery (CD).

Study Design: This is a multi-center retrospective cohort study of non-labor, term, singleton, non-anomalous births via CD under neuraxial anesthesia from 2013-2019. Primary outcome was fetal acidosis defined as umbilical artery pH < 7.1. Univariable and multivariable logistic regression were used to determine the likelihood of fetal acidosis relative to maternal factors, surgical factors, and both. Receiver–operating characteristic (ROC) curves evaluated the predictive accuracy of each model, comparing the area under the curve (AUC) using the DeLong test. Best-subset selection identified the factors that best predicted the primary outcome with possible overfitting addressed via k-fold cross-validation (5 repeated 10 fold validation).

Results: Fetal acidosis was present in 159 (2.5%) births included in this study. In a model of only maternal factors, predictors of fetal acidosis were body mass index (BMI), insurance type, and gestational diabetes (gDM). In a model of only surgical factors, predictors were time from anesthesia placement to delivery and hypotension (systolic blood pressure [BP] < 90 or diastolic BP < 50). In a combined model, predictors were BMI, gDM, time from anesthesia to delivery, and hypotension. Comparing the performance of all models, the combined maternal/surgical model performed better (AUC=0.77) than either the maternal (AUC=0.72) or surgical (AUC=0.70) (DeLong test p< 0.001). Using best-subset analysis, the model with the highest predictive accuracy included only obesity and hypotensive episodes (BIC=1383, AUC=0.74).

Conclusion: The etiology of fetal acidosis in non-labor, term, non-anomalous singleton births via CD is multifactorial, with the most predictive model including both maternal and surgical factors. Prenatal interventions to optimize metabolic health, as well as interventions to prevent hypotension or reduce time from anesthesia placement to delivery may reduce incidence of fetal acidosis.