TUESDAY, Sept. 26 (HealthDay News) -- Thyroid cancer patients treated with radioiodine-131 have significantly more menstrual anomalies than women who do not undergo iodine treatment, but most go on to have normal pregnancies, researchers report in the September issue of Fertility and Sterility.
Chrissa Sioka, M.D., of the Army Share Found Hospital in Athens, Greece, and colleagues compared 45 thyroid cancer patients under age 40 treated with radioiodine-131 between December 1996 and May 2003, with 83 controls.
The researchers found that 31.1 percent of the treated women had irregular menstrual cycles after treatment, including 17.8 percent who had normal cycles before treatment, and 13.3 percent whose anomalies predated treatment and increased afterwards. By contrast, only 14.5 percent of controls had menstrual anomalies. Radioiodine treatment caused a significant increase in menstrual anomalies; these worsened as patients aged. However, none of the seven children borne by six of the 45 patients were premature; there were no miscarriages.
"The study found a significant increase of patients with menstrual cycle and/or menses irregularities after treatment with radioiodine-131," the authors write. "However, therapy with radioiodine-131 did not result in any subsequent pregnancy abnormalities such as premature births or miscarriages."