The association between type of conception through medically assisted reproduction and childhood cognition: A Danish population-wide cohort study

Abstract

BackgroundPrevious research has found that children conceived through medically assisted reproduction (MAR) on average has cognitive outcomes on par with or above naturally conceived children. However, previous work has been unable to consider the relationship at a full population level nor consider heterogeneity across type of MAR.MethodsWe use all Danish live births in the years 2006-2009 (n=259,608) with indicator for MAR conceptions (n=13,554). The dependent variable is the within-year-and-grade standardized test scores carried out in second and third grade in primary schools. We compare the test scores for spontaneously conceived (SC) children and conceived through intra-urine insemination (IUI) and assisted reproductive technologies (ART). We estimate the ordinary least squares regressions: (1) a baseline model only adjusted for birthyear; (2) a model adjusted for birth-related confounders; (3) a model also adjusted for socio-demographic family characteristics, and whether child is young (old) for grade.ResultsAt baseline, ART conceived [grade 2: 𝛽 = 0.106, 95% confidence interval (CI): 0.081, 0.130; grade 3: 𝛽 = 0.094, 95% CI: 0.064, 0.122] and IUI conceived [grade 2: 𝛽 = 0.149, 95% CI: 0.117, 0.181; grade 3: 𝛽 = 0.143, 95% CI: 0.101, 0.185] performed better in tests than SC peers. After adjusting, ART conceived performed worse [grade 2: 𝛽 = −0.035, 95% CI: -0.059, -0.011; grade 3: 𝛽 = −0.038, 95% CI: -0.067, -0.008] than SC peer, and IUI conceived performed as well as SC peers [grade 2: 𝛽 = 0.017, 95% CI: -0.014, 0.048; grade 3: 𝛽 = 0.017, 95% CI: -0.022, 0.060] and better than ART conceived [grade 2: 𝛽 = 0.052, 95% CI: 0.014, 0.089; grade 3: 𝛽 = 0.057, 95% CI: 0.007, 0.105].ConclusionART conceived children do worse in language and math tests than SC peers, but IUI children do not differ from SC peer. Results likely reflect differences in selection of potential parents into type of MAR as well as consequences of differences in fecundability.Key messagesWe study the cognitive outcome in mid-childhood for children conceived through assisted reproductive technologies (ART), intra-urine insemination (IUI), and spontaneous conception (SC) in the country with the highest medically assisted reproduction birth rate in the world.At baseline, children conceived through ART and IUI performed better on low stakes standardized tests than did their SC peers.After adjusting for birth, child, and family characteristics, IUI children performed as well as SC children, whereas ART conceived children preformed worse. Gradients were larger for mothers with educational below university.There exists heterogeneity across MAR treatment types with regard to children’s outcomes.