Subclinical hypothyroidism: levothyroxine improves pregnancy outcomes

  • Rao M & al.
  • Hum Reprod Update
  • 1 May 2019

  • International Clinical Digest
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Takeaway

  • Supplementation with levothyroxine (LT4) is associated with reduced risk for pregnancy loss and preterm birth in pregnant women with subclinical hypothyroidism (SCH) and/or thyroid autoimmunity (TAI), according to a systematic review and meta-analysis.

Why this matters

  • SCH and TAI are associated with adverse pregnancy outcomes.

Key results

  • LT4 was associated with decreased rates of pregnancy loss (relative risk [RR], 0.56; P<.0001 and preterm birth in women with sch tai.>
  • In women with SCH, LT4 was associated with decreased risk for pregnancy loss (RR, 0.43; P=.001), but not preterm birth (RR, 0.67; P=.13).
  • In women with SCH, LT4 was associated with decreased risk for pregnancy loss after in vitro fertilization/intracytoplasmic sperm injection (RR, 0.27; P=.001).
  • In women with TAI, LT4 was associated with decreased risk for pregnancy loss (RR, 0.63; P=.009) and preterm birth (RR, 0.68; P=.04).
  • In women with TAI, LT4 was associated with decreased risk for pregnancy loss and preterm birth after natural conception (RR, 0.61 [P=.009] and RR, 0.49 [P=.04], respectively).

Study design

  • 13 studies (8 randomized controlled trials and 5 retrospective studies, N=7970 women) were included.
  • Funding: Kunming Medical University.

Limitations

  • Limited number of included studies, particularly in subgroup analysis.