A new population-based reference curve for symphysis-fundus height

Area of Science:

• Obstetrics and Gynecology
• Maternal-Fetal Medicine
• Biostatistics

Background:

• Accurate symphysis-fundus (SF) height measurement is crucial for monitoring fetal growth.
• Existing reference curves may not reflect current obstetric populations or methodologies.

Purpose of the Study:

• To develop a new gestational-age-specific percentile curve for symphysis-fundus (SF) height.
• To investigate the impact of maternal and fetal covariates on SF height measurements.

Main Methods:

• A population-based register study involving 42,018 ultrasound-dated singleton pregnancies.
• Non-linear regression analysis was used to construct the SF height reference chart.
• Data collected from antenatal clinics in Västra Götaland County, Sweden (2005-2010).

Main Results:

• The new SF height curve shows linear growth until term, with higher median values than older Norwegian and Danish curves.
• Compared to the previous Swedish curve, higher median SF height values were observed after 34 weeks gestation.
• Maternal pre-pregnancy weight and height were identified as the most significant covariates affecting SF height.

Conclusions:

• The developed SF height reference curve presents a distinct pattern compared to older Scandinavian curves.
• This new curve may better represent contemporary pregnant populations and methodological advancements.
• The curve's ability to be adjusted for maternal and fetal covariates allows for personalized pregnancy monitoring.