Babies conceived by IVF tend to be shorterGoogle Images

When age, sex, and parents’ height are all accounted for, children conceived under the influence of fertility drugs average between 2 and 2.5 cm shorter than children conceived naturally, the Irish Examiner reported.

Tim Savage, pediatrician and Clinical Research Fellow at the University of Auckland, will publish the results of his new study next month in Human Reproduction, a medical journal. Dr. Savage originally hails from Ballygarvan, Co. Cork.

The study contrasted 84 children conceived using fertility drugs but no other fertility intervention with 258 children conceived with no fertility intervention. The children were all between the ages of three and 10, and efforts were also made to account for differing ethnicities and socioeconomic situations.

As to be expected with a height difference of only 2.5 cm, the children conceived with fertility drugs are still within a normal, healthy height range, according to Dr. Savage. X-rays of the children’s hands reveal comparable bone maturity to the group without fertility intervention.

The children conceived with fertility drugs have on average slightly lower body mass indices —  a healthy sign — and comparable cholesterol levels to those conceived without the drugs, according to the Examiner.

Interestingly, previous studies have suggested that children conceived by in vitro fertilisation — a completely different process — are slightly taller than those conceived naturally.

Fertility drugs like clomiphene have been around since the 1960s; at present, between three and seven percent of children in the United States are conceived with fertility drugs.

The study is part of an ongoing investigation into the influence of mothers’ age and fertility treatments on their children’s growth and metabolism, the Examiner reported.