Levothyroxine Treatment in Pregnant Women with Thyrotropin Levels Ranging Between 2.5 and 10 mIU/L: A Propensity Score Matched Analysis
Authors' conclusion
LT4 treatment was significantly associated with a lower risk of pregnancy loss and a higher risk of small-for-gestational-age infants in pregnant women with TSH levels of 2.5-10 mIU/L. An increased risk of preterm birth was observed in the LT4-treated group among TPOAb-positive participants with TSH levels of 2.5-4.0 mIU/L.
Study context
- Population
- Chinese pregnant women with first-trimester TSH 2.5–10 mIU/L and normal free thyroxine (11.8–18.4 pmol/L)
- Participants
- 4,370 women668 matched pairs
- Exposure
- Levothyroxine (LT4) treatment vs no LT4 treatment
- Outcome
- Adverse pregnancy outcomes:
- Pregnancy loss
- Small-for-gestational-age infants
- Preterm birth
- Other complications
- Follow-up
- Completion of pregnancy
Methodological detailspropensity-score matched, 1:1 nearest-neighbor matching
- Propensity-score matched
- 1:1 nearest-neighbor matching
Main finding
As reported in the abstract
Adverse pregnancy outcomes (propensity score matching (PSM) cohort)
LT4-treated vs UntreatedRelative risk (95% CI)
Pregnancy loss; decreased risk with LT4
0.528(0.344–0.812)
SGA infants; increased risk with LT4
1.595(1.023–2.485)
Observational data: associations, not effects.
Further findings
| Outcome | RR (95% CI) | |
|---|---|---|
| Preterm birth, TPOAb-positive with high-normal TSH (2.5-4.0 mIU/L)LT4-treatedvs UntreatedIncreased risk with LT4 | 2.214 (1.016–4.825) | |
| 0.20.5125Relative risk (log scale) |
Subgroups by thyroid peroxidase antibody (TPOAb) status and TSH level
- Effects of LT4 on pregnancy loss and SGA mainly from TPOAb-negative participants
Parts of this Brief are withheld: the automatic checks could not confirm them against the abstract.
Original publication
Levothyroxine Treatment in Pregnant Women with Thyrotropin Levels Ranging Between 2.5 and 10 mIU/L: A Propensity Score Matched Analysis. Thyroid. Published 9 May 2024. doi:10.
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