Context:

Concern has been raised about the safety of assisted reproduction techniques (ART) for the offspring.

Objectives:

To investigate postnatal growth and growth factors in children born after intra-cytoplasmatic sperm injection (ICSI) and in vitro fertilisation (IVF).

Design:

Two cohorts: a population-based longitudinal infant cohort 0-36 months (236 ICSI, 173 IVF, 1530 naturally conceived (NC)) and a cross sectional child cohort at 5 yr (68 ICSI, 67 IVF, 70 NC).

Intervention:

Anthropometrical measurements at birth, 3, 18, 36 (infant cohort) and 60 months (child cohort), blood samples at 3 or 60 months

Main outcome measures:

Serum IGF-I, IGFBP-3, height, weight, head and abdominal circumference, BMI, fat folds

Results:

Anthropometrical measurements showed no significant differences between ICSI and IVF children and controls in either cohort. However, singleton ICSI girls (3.4 (0.6) kg, P = 0.008) had a slightly lower birth weight than IVF (3.5 (0.5) kg) and NC girls (3.5 (0.5) kg). Birth weights of singleton boys (3.6 (0.5) kg), twin boys (2.6 (0.6) kg) and twin girls (2.4 (0.5) kg) did not differ between types of conception. Infant cohort: In three months old singletons from the infant cohort, serum IGF-I was lower in ICSI (78 (26) ng/ml) than NC boys (94 (27) ng/ml, P < 0.001); and in IVF (74 (34) ng/ml) compared with NC girls (93 (43) ng/ml, P = 0.011). ICSI children were also smaller than their target height (SDS) at 3 yr of age (mean -0.91 (1.2) compared with NC children (-0.61 (0.9), P = 0.033). Child cohort: Target height attainment (SDS) and growth factors did not differ between the three groups.

Conclusions:

The overall growth pattern of ICSI and IVF children in both cohorts was normal. Our findings of subtle differences in target height attainment and serum IGF-I levels between infants born after ART and controls may not be clinically significant. However, these observations indicate that further systematic follow-up of growth and puberty in these children is needed.