Sex difference in fetal head growth

Area of Science:

• Obstetrics and Gynecology
• Fetal Development
• Medical Imaging

Background:

• Accurate estimation of gestational age is crucial for optimal pregnancy management and outcomes.
• Ultrasound measurement of the fetal biparietal diameter (BPD) is a common method for dating pregnancies.
• Existing growth charts may not fully account for sex-specific fetal growth patterns.

Purpose of the Study:

• To prospectively measure fetal biparietal diameter (BPD) growth during the second and third trimesters.
• To develop sex-specific fetal head growth curves.
• To evaluate the impact of sex-specific growth on the accuracy of pregnancy dating.

Main Methods:

• Prospective longitudinal study design.
• Measurement of fetal biparietal diameter (BPD) in a cohort of fetuses.
• Fitting of linear-cubic equations to individual fetal growth data.
• Generation of mean growth curves for male and female fetuses.

Main Results:

• Significant differences were observed in the head growth trajectories between male and female fetuses.
• Individual fetal growth data were modeled using linear-cubic equations.
• Mean growth curves demonstrated distinct patterns for males and females.

Conclusions:

• Fetal head growth exhibits significant sex-specific differences.
• Relying on non-sex-specific BPD measurements for pregnancy dating, particularly around 16 weeks gestation, can introduce errors.
• Sex-specific fetal growth data may improve the accuracy of gestational age estimation.