Fertility treatment and cardio-metabolic risk factors in middle childhood

Research question: Is growth or blood pressure altered among children conceived by fertility treatment compared with children conceived without use of treatment? Design: The Upstate KIDS birth cohort originally oversampled for infants conceived by fertility treatment, including by IVF and intracytoplasmic sperm injection, by ovulation induction intrauterine insemination (IUI), or both. A total of 1658 families completed annual questionnaires for children aged 6–10 years, including children's weight, height and blood pressure as reported from paediatric visits. Age- and sex-specific z-scores of weight, height and body mass index (BMI) were calculated. Mixed effects models were applied to assess differences for children conceived by any fertility treatment (n = 541), and by IVF/ICSI (n = 258) and ovulation induction and ICSI (n = 283) separately compared with children conceived without treatment (n = 968), adjusting for sociodemographic and other factors. Results: Children conceived by any fertility treatment did not differ in anthropometry or blood pressure compared with children not conceived by treatment. Children conceived by ovulation induction and IUI were slightly smaller than children conceived without treatment in both weight-for-age (–0.19, 95% CI –0.35 to –0.03; P = 0.02) and height-for-age (–0.27, 95% CI –0.47 to –0.08; P = 0.01) z-scores. Lower systolic blood pressure (–1.55 mmHg; 95% CI –3.02 to –0.07; P = 0.04) was also observed but not after accounting for height (P = 0.12). Children conceived by IVF/ICSI were similar in weight, height, BMI and blood pressure, but had slightly larger waist circumference (1.41 cm; 95% CI 0.36 to 2.46; P = 0.01). Conclusions: Children conceived by ovulation induction and IUI were slightly smaller in middle childhood than children not conceived by treatment but remained in the normal range of growth. Overall, these findings point to reassuring growth and blood pressure levels for children conceived by fertility treatments.