Thyroid Research Thyroid Research Archive Thyroid Cancer

Treatment with radioiodine does not decrease fertility in women with thyroid cancer

(July 2002)

The background of the study. Some women with thyroid cancer treated with high doses of radioiodine have transient ovarian dysfunction, but whether their fertility is reduced is uncertain. In this study the frequency of menstrual disturbances and pregnancies in women with thyroid cancer who had been treated with radioiodine was determined.

How the study was done. The study subjects were 496 women less than 40 years old with papillary or follicular thyroid cancer who were treated with surgery and then radioiodine and survived for at least two years thereafter. The women were asked about their menstrual and obstetric histories and their desire for children during follow-up visits or by mail.

After surgery, 322 women (65 percent) received a single dose of radioiodine, and 174 women (35 percent) received multiple doses because they had persistent or recurrent tumor. The women were advised not to become pregnant for one year after each treatment.

The results of the study. Eighty-seven women (18 percent) had died or were lost to follow up. Among the remaining 409 women, 326 (80 percent) had normal menstrual cycles, 49 (12 percent) had transient menstrual irregularity, and 34 (8 percent) had transient amenorrhea. No woman had permanent amenorrhea.

A total of 133 women (33 percent) reported that they did not want to have children and used contraception. Among the 276 women (67 percent) who wanted to have children, 275 had a total of 427 children.

The conclusions of the study. In women with thyroid cancer radioiodine therapy may transiently decrease ovarian function, but it has no long-term effect on fertility.

The original article. Vini L, Hyer S, Al-Saadi A, Pratt B, Harmer C. Prognosis for fertility and ovarian function after treatment with radioiodine for thyroid cancer. Postgrad Med J 2002;78:92-3.