Journal of Human Reproductive Sciences (Jan 2022)

Relationship between maternal serum thyroid-stimulating hormone and in vitro fertilisation-conceived pregnancy outcomes

  • Ayla Coussa,
  • Thomas M Barber,
  • Zakwan Khrait,
  • Samer Cheaib,
  • Hayder A Hasan

DOI
https://doi.org/10.4103/jhrs.jhrs_168_21
Journal volume & issue
Vol. 15, no. 2
pp. 163 – 170

Abstract

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Background: Thyroid dysfunction impairs female fertility and pregnancy outcome. Optimal preconception and gestational TSH level is still debatable in IVF-conceived pregnancies. Aims: To explore the relationships of IVF success and pregnancy outcomes with maternal serum levels of TSH (at both preconception and 12-week IVF-conceived pregnancy). Also, to confirm or refute the recommended TSH level ≤2.5μIU/mL. Setting and Design: Retrospective cohort. Material and Methods: 158 IVF-conceived pregnant women and 117 age-matched controls non-pregnant (≤39years, BMI 18.5-38kg/m2) were recruited. Preconception and 12-week IVF-conceived pregnancy serum samples were analysed for reproductive hormones, fasting glucose, insulin and TSH levels. Data of pregnant women at 28 weeks for GDM screening (75-gram OGTT) and up until delivery were included. Statistical Analysis: Binary logistic regression used to predict association between preconception TSH levels and IVF success, and pregnancy outcomes. Association of delta change of hormones was determined with linear regression. Significance level P≤0.05 with 95% confidence interval (CI). Results: Overall, median (IQR) age was 32(6)years, BMI 25.4(6.9)kg/m2, HbA1c 5.2(0.52)% and TSH 1.82(1.4)μIU/mL. There was no significant association between preconception TSH level and IVF success rate. During the first trimester of IVF-conceived pregnancy, delta change in TSH level was associated with that of progesterone (P=0.03). 12-week gestation TSH level did not predict adverse pregnancy outcomes (i.e. onset of GDM, delivery type and premature delivery); but a higher TSH level predicted earlier delivery in weeks. There was a higher risk of delivery by caesarean section when TSH>2.5μIU/mL. Conclusion: Variation of maternal TSH within normal range (0.4-4.0μIU/mL) at preconception and 12-week gestation has no predictive effect on IVF success and pregnancy outcomes in IVF-pregnancy. Our data provide no support for a recommended preconception TSH level ≤2.5μIU/mL in IVF-conceived pregnancy, but rather promote a preconception TSH level within normal range.

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