Gestational age: comparing estimation methods and live births' profile

Area of Science:

• Obstetrics and Gynecology
• Public Health
• Perinatology

Background:

• Accurate gestational age (GA) estimation is crucial for perinatal care and research.
• Discrepancies in GA estimation methods can impact clinical and epidemiological outcomes.
• Understanding factors influencing GA recording is essential for data quality in live birth certificates (LBC).

Purpose of the Study:

• To identify factors associated with the gestational age (GA) estimation method recorded on live birth certificates (LBC).
• To compare outcomes based on different GA estimation methods in São Paulo city (CSP) from 2012-2019.

Main Methods:

• A cross-sectional, population-based study utilized the Live Birth Information System.
• Descriptive and comparative analyses were performed based on GA estimation methods.
• Univariate and multivariate logistic regression identified predictor variables for the chosen GA estimation method.

Main Results:

• Gestational age (GA) estimated by the last menstrual period (LMP) was used in 39.9% of cases, compared to 60.1% for other methods (physical examination, ultrasound).
• LMP-based GA was more common among older, white, more educated mothers with partners, for cesarean births, and with private funding.
• Public funding was associated with a 2.33 times higher likelihood of using other methods (OM) over LMP. The proportion of preterm infants (<37 weeks) was 26.5% higher when GA was estimated by LMP.

Conclusions:

• Higher prematurity rates were observed with GA estimated by LMP in São Paulo, suggesting potential overestimation.
• Healthcare funding source emerged as the most significant predictor for the GA estimation method recorded on LBCs.
• Caution is advised when comparing GA data derived from different estimation methods due to potential biases.