Improved in Vitro Fertilization Outcomes after Treatment of Subclinical Hypothyroidism in Infertile Women

ObjectiveTo assess the effect of treatment of maternal subclinical hypothyroidism on infertility outcome.MethodsBetween April 1, 2006, and April 22, 2007, we conducted a prospective, randomized trial in infertile women with subclinical hypothyroidism who elected to undergo in vitro at the Shatby University Hospital for Women in Alexandria, Egypt. Patients were randomly assigned to 2 groups: treatment group (group A) and placebo group (group B). Male-factor infertility was ruled out. One month before the assisted reproduction technology procedure, group A underwent levothyroxine treatment with a dosage of 50 to 100 mcg daily, while group B started placebo. All patients underwent controlled ovarian stimulation. Patients who achieved pregnancy were followed up throughout their pregnancy until delivery. Levothyroxine treatment and placebo were maintained throughout pregnancy in group A and group B, respectively.ResultsMean thyrotropin value was significantly lower in group A than in group B (1.1 ± 0.3 mIU/L vs 4.9 ± 0.7 mIU/mL, respectively). Mean number of retrieved oocytes was similar in both groups (6.19 ± 0.74 [group A] vs 6.08 ± 0.79 [group B]). Miscarriage rate was significantly lower in group A than in group B (9% vs 13%, respectively), and the clinical pregnancy rate and delivery rate were significantly higher in group A than in group B (35% and 10% vs 26% and 3%, respectively), indicating that the quality, not the quantity, of retrieved oocytes was more important.ConclusionThese preliminary data suggest that levothyroxine supplementation should be recommended to achieve clinical pregnancies in women with subclinical hypothyroidism who are undergoing in vitro fertilization–intracytoplasmic sperm injection. (Endocr Pract. 2010:16: 792-797)