Association of Preconception Thyrotropin Levels With Fecundability and Risk of Spontaneous Abortion in China.
JAMA Netw Open
; 5(8): e2228892, 2022 08 01.
Article
in En
| MEDLINE
| ID: mdl-36044217
ABSTRACT
Importance Abundant evidence suggests thyroid dysfunction is associated with adverse pregnancy outcomes. However, associations of preconception thyrotropin levels outside of reference range with reproductive health outcomes are not well characterized. Objective:
To evaluate the associations of preconception thyrotropin levels with time to pregnancy (TTP) and risk of spontaneous abortion (SA). Design, Setting, andParticipants:
This population-based cohort study used data from the Chinese National Free Prepregnancy Checkups Project. Female participants aged 20 to 49 years who were trying to conceive were enrolled between January 1, 2013, and December 31, 2016, for the analysis of TTP or SA. Data were analyzed between August 1, 2020, and July 5, 2021. Exposures Levels of thyrotropin within 1 year prior to pregnancy. Main Outcomes andMeasures:
The main outcomes were TTP, assessed using hazard ratios (HRs), and SA, assessed using odds ratios (ORs), according to preconception thyrotropin levels. Thyrotropin dose-response associations were assessed using restricted cubic spline regression.Results:
Among 11â¯194â¯002 female participants (mean [SD] age, 27.56 [5.10] years) in the TTP cohort, 4â¯739â¯421 (42.34%) participants became pregnant within 1 year. Both low and high preconception thyrotropin levels were associated with delayed TTP compared with thyrotropin levels of 0.37 to 2.49 mIU/L (thyrotropin <0.10 mIU/L HR, 0.90; 95% CI, 0.89-0.92; thyrotropin 4.88-9.99 mIU/L HR, 0.86; 95% CI, 0.86-0.87; thyrotropin ≥10.00 mIU/L HR, 0.78; 95% CI, 0.77-0.79). In the SA analysis cohort including 4â¯678â¯679 pregnancies, 108â¯064 SA events (2.31%) were documented. High thyrotropin groups showed an increased risk of SA compared with the group with thyrotropin levels of 0.37 to 2.49 mIU/L (thyrotropin 4.88-9.99 mIU/L OR, 1.33; 95% CI, 1.28-1.38; thyrotropin ≥10.00 mIU/L OR, 1.25; 95% CI, 1.14-1.36). Preconception thyrotropin levels showed an inverted J-shaped dose-response association with TTP (χ2 = 311.29; nonlinear P < .001) and a J-shaped dose-response association with SA (χ2 = 58.29; nonlinear P < .001). Conclusions and Relevance In this cohort study, preconception thyrotropin levels outside of reference range were associated with increased risk of reduced fecundity and SA. These findings may provide insights for the implementation of preconception thyroid function screening and the design of future levothyroxine supplementation trials.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Thyrotropin
/
Abortion, Spontaneous
/
Fertility
Type of study:
Etiology_studies
/
Incidence_studies
/
Observational_studies
/
Risk_factors_studies
Limits:
Adult
/
Female
/
Humans
/
Pregnancy
Country/Region as subject:
Asia
Language:
En
Journal:
JAMA Netw Open
Year:
2022
Document type:
Article
Affiliation country:
China