Perinatology.  2023 Dec;34(4):165-170. 10.14734/PN.2023.34.4.165.

Estimating Gestational Age Using Fetal Biparietal Diameter at 11 to 14 Weeks in a Korean Population: A Retrospective Study

• Kim S
• Kwak DW
• Bae HJ
• Seo KY
• Kim MY
• Han YJ
• Ryu HM
• Chung JH

• KMID: 2550367
• DOI: http://doi.org/10.14734/PN.2023.34.4.165

Abstract

Objective
To evaluate fetal biparietal diameter (BPD) between 11 and 14 weeks of gestation in pregnant Korean women after in vitro fertilization (IVF) and to construct reference charts for esti mating gestational age (GA).
Methods
Data of Korean women with singleton pregnancies who conceived after IVF and underwent sonography between 11 and 14 weeks of gestation were retrospectively collected. BPD was measured from the outer to the inner edge of the parietal bone in a transverse plane. GA was calculated by adding 14 to the number of days between dates of oocyte retrieval and ultrasound scan. Fractional polynomial regression model was fitted to estimate GA in relation to BPD.
Results
BPD measurements were obtained for 960 fetuses. The BPD of Korean pregnancies was similar to previously described estimations at 12 weeks of gestation. However, it tended to be greater with advancing GA than those of non-Hispanic whites, non-Hispanic blacks, and Hispanics based on the Eunice Kennedy Shriver National Institute of Child Health and Human Development fetal growth studies. The best-fit equation for estimating GA from BPD was GA (day)=89.5684− (1.4667×BPD)+(0.0635×BPD² ) with standard deviation=−0.4532+ (0.1007×BPD).
Conclusion
Ethnic differences may exist in fetal BPD during the first trimester. The described chart can improve the accuracy of estimating GA in pregnant Korean women.

Keyword

Biparietal diameter; In vitro fertilization; Gestational age; First trimester