Objective: To quantitate the potential effectiveness and monetary costs of a policy of elective cesarean delivery for fetal macrosomia diagnosed by ultrasound.
Design: A decision analytic model was constructed to compare 3 policies: (1) management without ultrasound; (2) ultrasound and elective cesarean delivery for estimated fetal weight of 4000 g or more (4000-g policy); and (3) ultrasound and elective cesarean delivery for estimated fetal weight of 4500 g or more (4500-g policy). The impact of maternal diabetes was analyzed separately. Probability data used in the decision analytic model were summarized from the literature and supplemented with unpublished data from the Collaborative Trial of Preterm Birth Prevention. Costs were estimated from the literature, regional reimbursements, and clinical practice data.
Main outcome measures: Rates of shoulder dystocia and permanent brachial plexus injury, and both the number of additional cesarean births and monetary costs per permanent brachial plexus injury averted.
Results: In the baseline analysis for nondiabetic women, the ultrasound policies increased both the cesarean delivery rate and costs, while decreasing the rate of shoulder dystocia and brachial plexus injury. For each permanent brachial plexus injury prevented by the 4500-g policy, 3695 cesarean deliveries were performed at an additional cost of $8.7 million, vs 2345 cesarean deliveries and $4.9 million with the 4000-g policy. In the baseline analysis for diabetic women, with all 3 policies, rates of cesarean delivery, shoulder dystocia and brachial plexus injury, and total costs were higher than for nondiabetic women. However, more favorable ratios for both cesarean deliveries and cost per permanent injury avoided were observed: 443 deliveries and $930 000, respectively, with the 4500-g policy, and 489 deliveries and $880 000, respectively, with the 4000-g policy. Sensitivity analysis confirmed the general robustness of these findings.
Conclusions: For the 97% of pregnant women who are not diabetic, a policy of elective cesarean delivery for ultrasonographically diagnosed fetal macrosomia is medically and economically unsound. In pregnancies complicated by diabetes, such a policy appears to be more tenable, although the merits of such an approach are debatable.