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Gender-related differences in fetal heart rate during first trimester
D S McKenna1, G Ventolini, R Neiger
1Department of Obstetrics and Gynecology, Wright State University, Dayton, OH 45409-2902, USA.
Fetal Diagnosis and Therapy
|December 16, 2005
Summary
Early fetal heart rate (FHR) does not differ significantly between male and female fetuses. This study found no statistical difference in FHR for predicting fetal sex in the first trimester.
Area of Science:
- Reproductive Medicine
- Fetal Development
- Obstetrics
Background:
- Many expectant parents seek early fetal sex determination.
- Commonly held beliefs suggest differences in fetal heart rate (FHR) between sexes.
Purpose of the Study:
- To investigate if fetal heart rate (FHR) in the first trimester differs significantly between male and female fetuses.
- To provide evidence-based information for early pregnancy gender prediction.
Main Methods:
- Prospective study of 477 singleton pregnancies with sonography before 14 weeks' gestation.
- Fetal heart rate (FHR) measured via m-mode by a single sonographer.
- Fetal gender determined by second-trimester sonography and confirmed at delivery.
Main Results:
- Average female FHR was 151.7 bpm (±22.7), and average male FHR was 154.9 bpm (±22.8).
- No statistically significant difference was observed in FHR between male and female fetuses (p=0.13).
- No significant differences in maternal age, gravidity, parity, or gestational age at the time of the first study.
Conclusions:
- Fetal heart rate (FHR) in the first trimester is not a reliable indicator of fetal sex.
- Dispels the myth that FHR can predict gender early in pregnancy.
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