Academic performance in adolescents aged 15-16 years born after frozen embryo transfer compared with fresh embryo transfer: a nationwide registry-based cohort study

Objective: To assess academic performance in singletons aged 15-16 years conceived after frozen embryo transfer (FET) compared with singletons born after fresh embryo transfer (ET) in Danish cohorts born from 1995 to 2001.

Design: Danish national registry-based cohort study.

Setting: Danish national registries.

Population: All 6495 singletons conceived after assisted reproductive technology (ART) treatment in Denmark from 1995 to 2001 [FET (n) = 423; fresh ET (n) = 6072].

Methods: Mean test scores on a national standardised and international comparable grading-scale. Comparisons of test score were first made in univariate analysis (Model 1) and secondly in a multivariate linear model (Model 2) adjusting for relevant reproductive and socio-demographic covariates such as the occupational and educational level of the parents. Sensitivity analyses on FET-IVF (in vitro fertilisation) versus fresh ET-IVF and FET-ICSI (intracytoplasmic sperm injection) versus fresh ET-ICSI were made. Linear mixed models were used to account for the correlation in test scores of siblings for continuous outcome.

Main outcome measures: Mean overall test score and test score in Danish, mathematics, English, and physics/chemistry.

Results: Crude and adjusted mean test scores were similar for adolescents conceived after FET compared with fresh ET. The crude mean difference was +0.11 (95% CI -0.11; 0.34), and the adjusted mean difference was +0.12 (95% CI -0.09; 0.34).

Conclusions: Adolescents conceived after FET had similar academic performance at 15-16 of years of age compared with children conceived after fresh ET.

Tweetable abstract: Using frozen embryos in fertility treatment does not affect school performance in Danish adolescents aged 15-16 years.