Detecting fetal macrosomia with abdominal circumference alone.

Area of Science:

• Maternal-fetal medicine
• Diagnostic imaging in obstetrics
• Fetal growth assessment

Background:

• Macrosomia, defined as birth weight greater than or equal to 4,000 grams, poses risks to both mother and infant.
• Accurate identification of macrosomia is crucial for appropriate obstetric management.
• Ultrasound-based measurements are commonly used to estimate fetal weight, but their accuracy in identifying macrosomia can vary.

Purpose of the Study:

• To evaluate the efficacy of abdominal circumference (AC) in identifying macrosomic fetuses at or beyond 37 weeks of gestation.
• To determine the diagnostic performance of AC for macrosomia using receiver-operating characteristic (ROC) curve analysis.

Main Methods:

• Prospective study involving 256 parturients at term.
• Sonographic measurement of abdominal circumference (AC) was performed.
• Receiver-operating characteristic (ROC) curve analysis and likelihood ratio calculation were used to assess AC's ability to differentiate between normal birth weight and macrosomia.

Main Results:

• The prevalence of macrosomia was 8.2% (21/256) with a mean gestational age of 39.1 weeks.
• An AC threshold of >= 350 mm was identified as indicative of macrosomic fetuses.
• The area under the ROC curve was 0.79 +/- 0.04, and the likelihood ratio for detecting macrosomia was 2.9 (95% CI, 2.1-4.0).

Conclusions:

• Abdominal circumference (AC) demonstrates slight utility in detecting macrosomia among term parturients.
• Further research with a larger sample size is required to obtain narrow confidence intervals for a clinically useful likelihood ratio.