Hypothyroidism during pregnancy: Controversy over screening and intervention

Prevalence, risk factors, and consequences of hypothyroidism among pregnant women in the health region of Lleida: A cohort study

BACKGROUND

Primary maternal hypothyroidism is defined as the increase of TSH levels in serum during pregnancy. Hypothyroidism in pregnancy is the second most common endocrine disease, after diabetes mellitus, with a prevalence ranging between 3.2 and 5.5%. Its variability depends on ethnical differences. Hypothyroidism in pregnancy is associated with other chronic diseases and fetal and maternal outcomes.

OBJECTIVE

To analyze the prevalence of hypothyroidism among multiethnic pregnant women, and to evaluate the comorbidity with chronic diseases and outcomes leaded during pregnancy and newborn.

METHODS

Retrospective observational cohort study in pregnant women during the years 2012-2018 in the health region of Lleida. The relationship of hypothyroidism with different variables was analyzed by calculating the adjusted odds ratio (aOR) and the 95% confidence intervals (CI) with multivariate logistic regression models.

RESULTS

We analyzed a sample of 17177 pregnant women, which represents more than 92% of the total of pregnant women in the health region of Lleida. The annual prevalence of hypothyroidism was 5.7-7.1%. According to the region of origin, the lowest prevalence was found in the population from Sub Saharian Africa (2.1%), while the highest was from Asia and the Middle East (8.6%). Other factors associated with hypothyroidism were age, hypertension, diabetes mellitus, and dyslipidemia. In addition, we did not observe an effect of hypothyroidism on the course of pregnancy, childbirth, and on the newborn. Finally, there was a good control of the disease during pregnancy.

CONCLUSIONS

The prevalence of hypothyroidism in pregnancy was 6,5% in this study which depends on the country of origin, lower values were found in Sub Saharian African women and higher in those from Asia and the Middle East. Hypothyroidism was associated with age, diabetes mellitus, arterial hypertension, or dyslipidemia, and was not related to the Apgar score or the weight of the newborn.

Correlation of Maternal Thyroid Stimulating Hormone Levels With Lipid Profile in Pregnant Women With Hypothyroidism

Introduction Pregnancy leads to changes in hormonal levels and lipid profile. Thyroid hormones play a crucial role in embryonic growth and fetal development. Untreated thyroid disease during pregnancy can lead to a high risk of complications. Aim The aim of the study is to examine the correlation between thyroid stimulating hormone (TSH) and lipid profile in pregnant women with hypothyroidism. Materials and methods This cross-sectional case-control study was conducted at the Biochemistry Department, Alfalah School of Medical Science & Research Centre, Dhauj, Faridabad, Haryana, India. The study consisted of 500 patients (250 cases and 250 controls) who fulfilled the inclusion and exclusion criteria. Of the 250 cases recruited, 23 cases were in the 2nd trimester and 209 cases were in the 3rd trimester. Blood samples were collected from the participants to assess their lipid profile and TSH levels.  Results The study showed a statistically significant difference between the mean TSH levels of hypothyroid pregnant females in the 2nd trimester (3.85 ± 0.59) and the 3rd trimester (4.71 ± 0.54). There was a significant positive correlation observed between TSH and Total Cholesterol, Triglycerides, and LDL-C in both the 2nd and 3rd trimesters. In the second trimester, there was a significant positive correlation observed between TSH & TC (r = 0.6634, p<0.0005), TSH & TG (r= 0.7346, p=0.00006), TSH & LDL (r= 0.5322, p= 0.008). In the third trimester, there was a significant positive correlation observed between TSH & TC (r = 0.8929, p<0.00001), TSH & TG (r= 0.430, p<0.00001), TSH & LDL (r= 0.168, p= 0.015). However, no significant correlation was found between TSH levels and HDL-C in either trimester. The correlation coefficient and p-value for TSH & HDL were r = 0.2083, p=0.340 in the second trimester, and r = 0.0189, p=0.2384 in the third trimester. Conclusion A significant increase in TSH levels in hypothyroid pregnant women was observed in the 3rd trimester compared to the second trimester. Moreover, a significant positive correlation was found between TSH and lipid profile (total cholesterol, triglycerides, and LDL) in both trimesters, but not with HDL. These findings highlight the importance of monitoring thyroid hormone levels in the later stages of pregnancy to avoid potential maternal & fetal complications.