Effects of increased thyroxine dosage pre-conception on thyroid function during early pregnancy

Abstract

Our results suggest that in hypothyroid women anticipating pregnancy (with serum TSH in the lower quartile of normal range), the pre-conception adjustment of L-T4 doses may result in adequate maternal thyroid function up to the first post-conception evaluation. The procedure seems safe and inexpensive; it may be a worthwhile treatment, at least in thyroidectomized women, in view of the well-known potential effects of even marginal maternal thyroid hypofunction on the subsequent IQ of the progeny.

Thyroxine replacement during super-ovulation for in vitro fertilization: a potential gap in management?

“…Conception rate was not altered, but miscarriage rate was lower in the thyroxinetreated group. A similar study was conducted by Rotondi et al (14). Hypothyroid women receiving thyroxine and planning pregnancy were randomized to continue a therapeutic dose or to increase to partially suppressive thyroxine dose to bring TSH into the lownormal reference range.…”

Treatment and screening of hypothyroidism in pregnancy: results of a European survey

“…It is well known that most hypothyroid women need an increased dose of L-T 4 from very early pregnancy (10). Indeed, about 25% women on L-T 4 replacement have biochemical evidence of under replacement at their first antenatal visit (11), which may be prevented by optimizing the L-T 4 dose before pregnancy (12). Other recommended approaches include advising the woman to increase the dose of L-T 4 by 30-50% (10) or by two tablets per week (5) as soon as pregnancy is confirmed.…”

Screening and management of hypothyroidism in pregnancy: Results of an Asian survey

“…Most hypothyroid women need an increased dose of L-T 4 from very early pregnancy [16,17]. Indeed, about 25% women on L-T 4 replacement have biochemical evidence of under replacement at their first antenatal visit [7], which may be prevented by optimizing the L-T 4 dose before pregnancy [18]. In the present study, 32% of responders would advise woman to increase the dose of L-T 4 by 30-50% and 11% by two tablets per week as soon as pregnancy is confirmed according to previous recommendations [3,4,19].…”