Fetal cardiac axis in non-anomalous pregnancies: does fetal gender or maternal body mass index (BMI) matter?

• Published in: The journal of maternal-fetal & neonatal medicine Vol. 29; no. 13; p. 2125
• Main Authors: Adekola, Henry, Soto, Eleazar, Dai, Jing, Puder, Karoline, Abramowicz, Jacques S
• Format: Journal Article
• Language: English
• Published: England 02.07.2016
• Subjects: Body Mass Index; Female; Fetal Development; Fetal Heart - diagnostic imaging; Fetal Heart - physiology; Fetus - physiology; Gestational Age; Humans; Lung - diagnostic imaging; Lung - embryology; Male; Organ Size; Pregnancy; Sex Factors; Ultrasonography, Prenatal; late ultrasound study; Early ultrasound study; fetal lung volume
• ISSN: 1476-4954
• DOI: 10.3109/14767058.2015.1077219

To determine if cardiac axis obtained at an early ultrasound study (11-15 weeks) differs from that obtained at a late ultrasound study (18-22 weeks) in the same fetus and to evaluate the impact of fetal gender and/or maternal body mass index (BMI). Cardiac axes of 324 non-anomalous fetuses at 11-15 weeks gestation were measured, with follow-up measurements obtained at 18-22 weeks. Comparisons were performed based on gestational age period, fetal gender and obese/non-obese maternal status. (1) Mean fetal cardiac axis did not change between 11 and 15 weeks; p = 0.8, (2) mean fetal cardiac axis was more levorotated at 11-15 weeks than measurements obtained at 18-22 weeks; 48.1 ± 7.1° versus 43.7 ± 8.9°; p < 0.0001, (3) male fetuses had less levorotated cardiac axis than female fetuses in late ultrasound studies but there was no difference between them at early ultrasound studies; 18-22 weeks male fetus, 42.7 ± 9.3° versus female fetus, 45.2 ± 8.3°; p = 0.02 and 11-15 weeks male fetus, 48.1 ± 7.0° versus female fetus, 48.4 ± 7.4°, p = 0.7, respectively, and (4) similar trends with the overall study population were observed in the comparison between fetuses of obese and non-obese women. Fetal cardiac axis remains stable at 11-15 weeks, becoming less levorotated at 18-22 weeks. This may be attributed to increments in fetal lung volume. The differences in cardiac axis measurements between male and female fetuses examined at 18-22 weeks may also be attributable to differences in increment of fetal lung volume during this gestational age period.