The effect of infertility medication on thyroid function in hypothyroid women who conceive.
OBJECTIVE
To determine whether infertility medications alter thyroid status in patients with treated hypothyroidism, and whether resulting pregnancies require additional thyroid supplementation compared with those conceived spontaneously.


METHODS
Prospective observational study of 18 infertility patients with treated hypothyroidism who conceived between July 2005 and July 2006 with or without infertility medications. Thyroid studies were performed prior to conception, at the time of pregnancy diagnosis, and approximately 6 weeks after an increase in thyroid replacement dose.


RESULTS
Orally medicated conceptions were similar to spontaneous conceptions on all thyroid related variables, and therefore the two groups were combined for analysis. Although there was a nonsignificant difference in thyrotropin (TSH) levels postconception (3.8 mIU/L vs. 2.2 mIU/L, p = 0.30), there was no difference in TSH levels after increase in thyroid replacement dose (1.7 mIU/L vs. 1.1 mIU/L, p = 0.30) between patients who conceived after gonadotropin stimulation compared with those who conceived spontaneously or with oral medications. The mean percent dose increases for the nongonadotropin and gonadotropin pregnancy groups were 30.6% and 32.4%, respectively.


CONCLUSIONS
Hypothyroid patients who conceive after gonadotropin stimulation or with oral medications for ovulation induction do not need additional thyroid supplementation compared with those who conceive spontaneously.
Davis
Lynn B
LB
Division of Reproductive Endocrinology and Infertility, Stanford University Medical Center, Palo Alto, California 94304, USA.
Lathi
Ruth B
RB
Dahan
Michael H
MH
D000284:Administration, Oral; D000328:Adult; D004958:Estradiol / Q000097:blood; D005260:Female; D006062:Gonadotropins / Q000627:therapeutic use*; D020249:Hormone Replacement Therapy / Q000379:methods*; D006801:Humans; D007037:Hypothyroidism / Q000150:complications / Q000188:drug therapy*; D007247:Infertility, Female / Q000150:complications / Q000188:drug therapy*; D010062:Ovulation Induction; D011247:Pregnancy; D011248:Pregnancy Complications / Q000188:drug therapy*; D011446:Prospective Studies; D013961:Thyroid Gland / Q000187:drug effects / Q000502:physiology; D013972:Thyrotropin / Q000097:blood; D013974:Thyroxine / Q000097:blood; D013975:Thyroxine-Binding Proteins / Q000378:metabolism; D014284:Triiodothyronine / Q000097:blood
D006062:Gonadotropins; D013975:Thyroxine-Binding Proteins; D014284:Triiodothyronine; D004958:Estradiol; D013972:Thyrotropin; D013974:Thyroxine