IVF pregnancy dating: Comparative analysis of gestational age estimation based on embryo transfer date and ultrasound measurements of crown-rump length

Abstract

Introduction. In in-vitro fertilization pregnancies, the precise date of conception is known. Relying solely on the embryo transfer date for pregnancy dating can lead to inaccuracies and mismanagement in prenatal care. This study aimed to compare gestational age estimated by first-trimester ultrasound measurements with gestational age determined by the known date of embryo transfer. Material and Methods. This retrospective study included 30 patients who conceived through in-vitro fertilization. Only patients with singleton pregnancies who underwent first-trimester ultrasound screening by a single sonographer between January 2008 and March 2024 were included. Gestational age was calculated for each patient based on ultrasound measurements of crown-rump length and the date of embryo transfer. Results. Gestational age estimated by ultrasound in our study was statistically significantly higher than that determined by the embryo transfer date. The mean difference was 0.9 days (?2.14, 95% confidence interval [0.1, 1.7]) (p<0.05), and a median difference was 0.5 days (interquartile range 0-2.75) (p<0.05). Conclusion. Gestational age estimated by crown-rump length was higher than that calculated by the known date of conception. For pregnancies conceived through in-vitro fertilization, it is advisable to consider both the date of embryo transfer and the gestational age calculated from ultrasound measurements for more accurate pregnancy dating.