Which Foetal-Pelvic Variables Are Useful for Predicting Caesarean Section and Instrumental Assistance?

Area of Science:

• Obstetrics and Gynecology
• Fetal Medicine
• Biomedical Engineering

Background:

• Accurate prediction of delivery mode is crucial for maternal and fetal well-being.
• Identifying key fetopelvic variables can optimize delivery management and reduce complications.
• Existing predictive models may not fully incorporate a comprehensive set of fetopelvic measurements.

Purpose of the Study:

• To identify and assess fetopelvic variables that effectively predict spontaneous vaginal delivery (SVD), caesarean delivery (CD), and instrument-assisted delivery (IAD).
• To evaluate the discriminatory power of various fetal and maternal pelvic measurements using statistical analysis.

Main Methods:

• A prospective study included 114 pregnant women.
• 43 maternal pelvic and 18 fetal variables were measured for each mother-fetus pair.
• Partial least squares-discriminant analysis was employed to differentiate between SVD, CD, and IAD groups.

Main Results:

• For SVD versus CD: Fetal size (transverse diameter, fetal weight) and maternal pelvic inlet dimensions (anteroposterior inlet) were significant predictors. A narrow pelvic inlet increased CD risk.
• For SVD versus IAD: Fetal variables, particularly bi-parietal diameter, were most important. Reduced anteroposterior outlet diameter and a narrow pubic arch increased IAD risk.
• The obstetric conjugate was found to be less useful in predicting delivery mode compared to the anteroposterior inlet.

Conclusions:

• The anteroposterior inlet is a valuable sagittal variable for predicting delivery outcomes.
• The obstetric conjugate diameter is not a reliable predictor for labor arrest.
• Combining sub-pubic angle, bi-parietal diameter, and anteroposterior outlet diameter aids in identifying risks for instrumental assistance.