Predicting macrosomia
Jason A Pates1, Donald D McIntire, Brian M Casey
1Department of Obstetrics and Gynecology, Madigan Army Medical Center, Tacoma, WA 98431, USA. jason.pates@nw.amedd.army.mil
Objective:
The purpose of this study was to evaluate the prediction of fetal macrosomia based on ultrasound estimates of fetal weight and amniotic fluid volume combined with clinical risk factors.
Methods:
A retrospective cohort study of women undergoing indicated obstetric ultrasound examinations within 7 days of delivery was conducted.
Results:
A total of 3115 women gave birth within 7 days of ultrasound examinations that included an estimated fetal weight (EFW) and an amniotic fluid index (AFI). Clinical risk factors were associated with an 8% positive predictive value for a birth weight of 4000 g or higher. Adding an ultrasound EFW of 4000 g or higher increased the positive predictive value to 62%. Adding an AFI of 20 cm or higher to the clinical risk factors and the ultrasound EFW further increased the positive predictive value to 71%.
Conclusions:
An ultrasound EFW of 4000 g or higher within 1 week of delivery combined with clinical risk factors and an increased AFI is associated with macrosomia at birth in 71% of cases.