Context: Euthyroid women positive for thyroid antibodies are prone to develop subclinical/overt hypothyroidism during gestation and seem to suffer from a poor outcome.
Objective: Assessing if patients with autoimmune thyroid disease undergoing Assisted Reproduction Technologies (ART) are afflicted by poor pregnancy and/or delivery rate and if the outcome is conditioned by pre-ART thyroid status.
Design: Prospective study since January 1999 until June 2006. Women undergoing ART were screened for TSH, FT4, TPOAb.
Setting: Division of Physiopathology of Human Reproduction.
Patients: A total of 464 euthyroid women were selected; 52 (11.2%) were TPOAb (+).
Main outcomes: The endpoints were pregnancy rate, miscarriage rate and obstetrical complications.
Results: No difference in pregnancy rate was observed between women with and without antibodies. The rates of miscarriage and pre-term delivery were higher in TPOAb (+) than TPOAb (−) [P=0.049; RR=1.1 (95% CI=0.981.25); P=0.023; RR=1.2 (95% CI=0.981.4), respectively]. In TPOAb (+), women who miscarried displayed higher TSH values before ART (2.8 mIU/L) compared to the ones who delivered or failed to become pregnant (1.6 and 1.7 mIU/L; P=0.032 and P=0.018 respectively).
Conclusions: In euthyroid women undergoing ART the pregnancy rate is not affected either by the presence of TPOAb or thyroid function. TPOAb (+) showed significantly increased number of miscarriages and pre-term deliveries; thyroid function before ART appears to play a pivotal role in determining the gestation outcome. These results show that thyroid autoimmunity and even a mild thyroid impairment represent risk factors for obstetrical complications (miscarriage and pre-term delivery). Further studies are required to ascertain possible benefits of levothyroxine in such patients.
01 - 05 Apr 2006
European Society of Endocrinology