Association between external pelvimetry and vertex delivery complications in African women

To assess association between external pelvimetry and delivery complications in vertex presentation.

Prospective cohort study of 2,413 pregnant women antenatally measured for height and external pelvimetry in four hospitals of the former Republic of Zaire.

Complications during delivery of single fetus weighing 2,000 g or more in vertex presentation. Cut-off values at risk for delivery complications were height and pelvic distances closest to the study population 10th percentile.

In univariate analysis, maternal height showed significant relative risk for predicting primary cesarean section for failure to progress: 2.0 (95% CI=1.0-4.1; p=0.050) and vacuum or forceps delivery: 15.7 (95%, CI=6.6-37.5; p<0.001). Selected external pelvic distances showed significant relative risks for predicting the following complications: primary cesarean section for failure to progress, elective repeat cesarean section, vacuum or forceps delivery and spontaneous intrapartum stillbirth. Among pelvic predictors, transverse diagonal (TD) of Michaelis sacral rhomboid area was associated with all of these complications. Intertrochanteric (IT) diameter was associated with three of them. The relative risks ranged from 2.3 (95% CI=1.1-6.3; p=0.030) to 9.6 (95% CI=4.1-22.5; p<0.001) for these strongest predictors.

External pelvic distances help to predict vertex delivery complications in African women. The predicted complications are compatible with the cephalopelvic disproportion concept (CPD). After validation of current results in a separate cohort, measurements of IT and/or TD are recommended to improve antenatal screening of women at risk for CPD in limited resources settings.