Treatment with estrogen to reduce the adult height of tall girls has been available since the 1950s. No randomized trials have examined the effect of estrogen therapy, however, which alters the development of the long bones and has been reported to reduce adult height by 2–10 cm.

In a retrospective cohort study, historical data from pediatric endocrinologists and self-referrals identified around 1,400 women who were assessed for estrogen therapy from 1959 onward. 780 of these women completed a survey about their fertility in later life. Half of them (the treatment group) actually received therapy; the other half (the control group) were assessed but not given hormone treatment.

Adverse Reproductive Effects

After adjusting for age, the researchers found that treated women were more likely to have tried for a year or more to become pregnant without success (80% increase compared with women in the control group).

They were also more likely to have seen a doctor because they were having difficulty becoming pregnant (80% increase) and were twice as likely to have taken fertility drugs, compared to women not given hormone therapy.

In terms of the time to first pregnancy, the women who had received estrogen therapy in adolescence were 40% less likely to conceive following unprotected intercourse in any given menstrual cycle.

“Although the possibility of adverse reproductive effects of oestrogen treatment for tall stature in girls has been acknowledged for many years, we believe ours is the first study to report longterm follow-up of the reproductive experiences of a large cohort of treated girls," comments lead investigator Alison Venn of the Menzies Research Institute, University of Tasmania, Australia.

Infertility Treatments Hide Problems

"Our findings indicate that exposure to high-dose oestrogens in adolescence is associated with impaired fertility in later life," Venn continues. "This effect was seen as both a reduced per cycle rate of conception in those who conceived, and as an increase in the risk of experiencing infertility," she noted.

"The availability of infertility treatments is likely to have contributed to the finding that women who were treated for tall stature had only a small decrease in the probability of eventually conceiving and having a live birth compared with untreated women,” Venn concluded.