Thyroxine therapy does not improve the outcome
of in vitro fertilization in women with autoimmune thyroiditis
(July 2005)
The background of the study. Autoimmune thyroid
disease has been associated with infertility and miscarriage. In
this study, pregnancy, miscarriage, and delivery rates were determined
in infertile women with autoimmune thyroiditis who were treated
with thyroxine (T4) or placebo and then underwent in vitro fertilization.
Infertile women who did not have autoimmune thyroiditis also were
studied.
How the study was done. The study subjects were
484 infertile women scheduled to undergo their first cycle of in
vitro fertilization and embryo transfer to the uterus. Among the
484 women, 72 (15 percent) had a high serum antithyroid peroxidase
antibody concentration. They were randomly assigned to receive T4
(1.0 ?g/kg per day) or placebo. One month later, assisted reproduction
was begun. T4 therapy was continued throughout any pregnancy.
After stimulation of the ovaries, oocytes were retrieved and fertilized
in vitro, and one to three embryos were transferred to the woman’s
uterus. Pregnancy was confirmed by high serum chorionic gonadotropin
concentrations and ultrasonography. The end points were pregnancy
rates, miscarriage rates, and delivery rates.
The results of the study. The mean age, reproductive
history, causes of infertility, and serum TSH and T4 concentrations
were similar in the three groups of women. The pregnancy rate was
also similar in the three groups (53 to 56 percent). Among the women
who became pregnant, the miscarriage rate was 25 percent in the
women with normal serum antibody concentrations, as compared with
40 and 47 percent in those with high serum antibody concentrations
treated with T4 and not treated, respectively. The respective delivery
rates were 75, 60, and 53 percent.
The conclusions of the study. The rate of pregnancy
in women undergoing in vitro fertilization and embryo transfer is
similar in women with and without high serum antithyroid antibody
concentrations. The rate of miscarriage is higher in the former
group, and among them it is not reduced by T4 treatment.
The original article. Negro R, Mangieri T, Coppola
L, Presicce G, Casavola EC, Gismondi R, Locorotondo G, Caroli P,
Pezzarossa A, Dazzi D, Hassan H. Levothyroxine treatment in thyroid
peroxidase antibody-positive women undergoing assisted reproduction
technologies: a prospective study. Hum Reprod 2005;20:1529-33.
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