Discrepancy in ultrasound biometric parameters of the head (HC--head circumference, BPD--biparietal diameter) in breech presented fetuses.

Abstract

BACKGROUND: A comparison of fetal ultrasonographic biometric parameters of the head (head circumference - HC, biparietal diameter - BPD) in breech presented fetuses. METHODS: Ultrasound biometry was performed in accordance with the method presented in the reference tables. In all breech presented fetuses, the HC, BPD and FL (femur length) were measured. High-risk and multiple pregnancies were excluded from the study. RESULTS: A total of 111 ultrasonographic biometries were performed between the 31(st) - 38(th) week of gestation. Fetuses in the breech position had a significantly lower BPD compared to HC and FL. The difference between BPD and HC was 16.2 days (95%Cl 14.3-18.1; p = 0.001). Maternal age at delivery was 20 - 36 years (average 28.1; median 28.0). CONCLUSIONS: According to our results, fetuses in the breech position have a significantly lower BPD compared to HC or FL. HC and FL parameters correlate with gestational age. In cases of ultrasonographic biometric discrepancy between BPD and FL, the fetal position should be taken into account. Breech-presented fetuses have an elongated head shape and ultrasound biometrics should evaluate its circumference (HC). It is important to responsibly interpret the results so as not to stress the expecting mother with suspicions of fetal pathology.