Objective: Older women are at an increased risk for unexplained stillbirth late in pregnancy. The purpose of this study was to compare 3 strategies for the prevention of unexplained fetal death in women aged 35 years and older. We compared usual care (no antepartum testing or induction before 41 weeks), weekly testing at 37 weeks with induction after a positive test, and no testing with induction at 41 weeks.
Method: We used a Markov model to quantify the risks and benefits of each strategy in terms of the number of antepartum tests, inductions, and additional cesarean deliveries per fetal death averted. Probability data used in the model were derived from obstetrical databases and the literature.
Results: Without a strategy of antepartum surveillance between 37 and 41 weeks, women aged 35 years and older would experience 5.2 unexplained fetal deaths per 1,000 pregnancies. For nulliparous women 35 and older, weekly antepartum testing initiated at 37 weeks would avert 3.9 fetal deaths per 1,000 pregnancies but would require 863 antepartum tests, 71 inductions, and 14 additional cesarean deliveries per fetal death averted. A strategy of no testing but induction at 41 weeks would avert 0.9 fetal deaths per 1,000 pregnancies and require 469 inductions and 219 additional cesareans per fetal death averted.
Conclusion: A strategy of antepartum testing in older women would reduce the number of unexplained stillbirths at term and would result in fewer inductions and cesareans per fetal death averted than a strategy of no antepartum testing but induction at 41 weeks.