Background: We aimed to determine whether children conceived with ovarian stimulation alone (OS(A)) would differ phenotypically and biochemically from naturally conceived children of fertile and subfertile parents.
Methods: Healthy pre-pubertal children aged 3-10 years, born at term, after singleton pregnancies were recruited in Auckland (New Zealand) and were allocated into three groups: (i) children conceived following OS(A) and naturally conceived children of (ii) subfertile and (iii) fertile parents. Anthropometric, endocrine and metabolic parameters were recorded. Children's heights and body mass index (BMI) were expressed as standard deviation scores (SDS) and corrected for genetic potential (i.e. parental height or BMI).
Results: Three hundred fifty-two children were studied: 84 OS(A) subjects and 268 naturally conceived controls consisting of 54 children of subfertile parents and 214 children of fertile parents. Children of subfertile and fertile parents did not differ in measured outcomes. Overall, OS(A) children were shorter than children of both subfertile (SDS: -0.08 ± 0.09 versus 0.32 ± 0.07; P= 0.001) and fertile (SDS: -0.08 ± 0.09 versus 0.45 ± 0.10; P= 0.004) parents when corrected for genetic height potential. OS(A) boys were shorter than boys of subfertile (SDS:-0.18 ± 0.14 versus 0.42 ± 0.16; P= 0.03) and fertile (SDS: -0.18 ± 0.14 versus 0.35 ± 0.08; P= 0.01) parents. There was also a trend towards OS(A) girls being shorter than girls of subfertile parents (P= 0.06), but not significantly shorter than those of fertile parents (P= 0.17). OS(A) children also had a lower corrected BMISDS than children of subfertile (SDS-0.90 ± 0.15 versus -0.37 ± 0.17; P= 0.06) and fertile (-0.90 ± 0.15 versus -0.34 ± 0.10; P= 0.008) parents. Among metabolic parameters, fasting glucose was lower in OS(A) children than that in children of fertile parents (4.62 ± 0.07 versus 4.81 ± 0.04; P= 0.006).
Conclusions: Conception after OS(A) was associated with shorter stature, particularly in boys, compared with naturally conceived children of fertile and subfertile parents.