Association Between Second-Trimester Dyslipidemia And The Risk Of Developing Preeclampsia Among Pregnant Women With Subclinical Hypothyroidism
Abstract
Background: Subclinical hypothyroidism (SCH) is one of the most common endocrine disorders encountered during pregnancy and has been increasingly recognized as a contributor to adverse maternal and fetal outcomes.
Aim: This study aimed to evaluate the association between second-trimester dyslipidemia and the risk of developing preeclampsia among pregnant women with subclinical hypothyroidism and to identify clinically useful biochemical markers for early prediction of preeclampsia.
Patients and Methods: A hospital-based case–control study was conducted at the Department of Obstetrics and Gynecology, Tikrit Teaching Hospital, Salah Al-Din Governorate, Iraq, from 1 October 2025 to 30 June 2026. A total of 120 pregnant women diagnosed with SCH during the second trimester were enrolled. The participants were divided into two equal groups: 60 women who subsequently developed preeclampsia (cases) and 60 women who remained normotensive throughout pregnancy (controls). fasting serum samples were analyzed for thyroid-stimulating hormone (TSH), free thyroxine (FT4), total cholesterol (TC), triglycerides (TG), low-density lipoprotein cholesterol (LDL-C), and high-density lipoprotein cholesterol (HDL-C).
Results: Women who developed preeclampsia had significantly higher serum TSH concentrations than controls (5.92 ± 1.31 vs. 4.51 ± 0.88 mIU/L, P < 0.001), whereas FT4 levels did not differ significantly (P = 0.148). Maternal lipid profile demonstrated significantly higher concentrations of TC (228.64 ± 29.81 vs. 198.73 ± 24.16 mg/dL), TG (242.51 ± 47.36 vs. 182.45 ± 36.28 mg/dL), and LDL-C (146.82 ± 26.14 vs. 118.41 ± 22.33 mg/dL), together with significantly lower HDL-C levels (41.62 ± 6.83 vs. 50.48 ± 7.22 mg/dL) among women with preeclampsia (all P < 0.001). Composite dyslipidemia was present in 81.67% of cases compared with 45.00% of controls (P < 0.001). Serum TSH demonstrated significant positive correlations with TC (r = 0.421), TG (r = 0.487), and LDL-C (r = 0.394), while HDL-C showed a significant inverse correlation (r = −0.336).
Conclusions: Pregnant women with subclinical hypothyroidism who subsequently developed preeclampsia exhibited significantly more pronounced dyslipidemia and higher serum TSH concentrations than those who remained normotensive. Elevated triglycerides, total cholesterol, LDL-C, increased TSH, reduced HDL-C, and higher maternal BMI independently predicted the development of preeclampsia.
