A comparison of propylthiouracil versus methimazole in the treatment of hyperthyroidism in pregnancy.
OBJECTIVE
Our purpose was to demonstrate that propylthiouracil and methimazole are equally effective and safe in the treatment of hyperthyroidism during pregnancy.


METHODS
Between 1974 and 1990 records were available on 185 pregnant patients with a history or diagnosis of hyperthyroidism. Ninety-nine patients were treated with propylthiouracil and 36 with methimazole. The response to therapy was compared with respect to the time to normalization of the free thyroxine index and the incidences of congenital anomalies and hypothyroidism.


RESULTS
The time to normalization of the free thyroxine index was compared in the two groups by means of survival analysis. The median time to normalization of the free thyroxine index on propylthiouracil and methimazole was 7 and 8 weeks, respectively (p = 0.34, log-rank test). The incidence of major congenital malformations in mothers treated with propylthiouracil and methimazole was 3.0% and 2.7%, respectively. No neonatal scalp defects were seen. One infant was overtly hypothyroid at delivery.


CONCLUSIONS
Propylthiouracil and methimazole are equally effective and safe in the treatment of hyperthyroidism in pregnancy.
Wing
D A
DA
Department of Obstetrics and Gynecology, Los Angeles County/University of Southern California Medical Center, Women's Hospital.
Millar
L K
LK
Koonings
P P
PP
Montoro
M N
MN
Mestman
J H
JH
D016009:Chi-Square Distribution; D015331:Cohort Studies; D000013:Congenital Abnormalities / Q000453:epidemiology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D006980:Hyperthyroidism / Q000188:drug therapy*; D015994:Incidence; D008713:Methimazole / Q000627:therapeutic use*; D011247:Pregnancy; D011248:Pregnancy Complications / Q000188:drug therapy*; D011256:Pregnancy Outcome; D011441:Propylthiouracil / Q000627:therapeutic use*; D011446:Prospective Studies; D011863:Radioimmunoassay; D012189:Retrospective Studies; D013974:Thyroxine / Q000097:blood; D014284:Triiodothyronine / Q000097:blood
D014284:Triiodothyronine; D008713:Methimazole; D011441:Propylthiouracil; D013974:Thyroxine