Pregnant women positive for anti-thyroperoxidase autoantibody and anti-thyroglobulin autoantibody during their first trimester are at increased risks for hypertensive disorders of pregnancy, according to findings published in Clinical Endocrinology.
Fang-Biao Tao, MD, PhD, of the department of maternal, child and adolescent health in the School of Public Health at Anhui Medical University in China, and colleagues evaluated data from the Ma’anshan Birth Cohort study on 2,893 pregnant women to examine the associations of maternal thyroid autoantibody positivity in the first and second trimesters with risks for hypertensive disorders of pregnancy.
Overall, 5.9% of participants had hypertensive disorders of pregnancy; 4.2% with gestational hypertension and 1.7% with preeclampsia. Participants with hypertensive disorders of pregnancy vs. those without had higher prepregnancy BMI (22.9 kg/m2 vs. 20.7 kg/m2; P < .001) and higher rates of diabetes in pregnancy (30.4% vs. 11.7%; P < .001).
The risk for hypertensive disorders of pregnancy was increased in participants with diabetes in pregnancy (OR = 2.76; 95% CI, 1.9-4) compared with participants without diabetes, and higher in participants with overweight (BMI, 18-24 kg/m2; OR = 2.46; 95% CI, 1.6-3.78) and obesity (BMI, 24-28 kg/m2; OR = 7.03; 95% CI, 3.79-13.04) compared with participants with normal weight (BMI, 18.5-24 kg/m2); risk was decreased in participants with low BMI (< 18.5 kg/m2; OR = 0.3; 95% CI, 0.15-0.6).
During the first trimester, 11.8% of participants were positive for anti-thyroperoxidase autoantibody (TPOAb), and 12.5% were positive for anti-thyroglobulin autoantibody (TgAb); rates decreased in the second trimester (TPOAb, 6.9%; TgAb, 5.1%).
The risk for hypertensive disorders of pregnancy was 1.8-fold higher in participants positive for TPOAb in the first trimester (OR = 1.8; 95% CI, 1.17-2.78) and 1.78-fold higher in those positive for TgAb in the first trimester (OR = 1.78; 95% CI, 1.16-2.73) compared with those without positivity, after adjustment for confounders. A borderline association was observed between TPOAb positivity in the second trimester and the risk for hypertensive disorders of pregnancy (OR = 1.69; 95% CI, 1-2.88), but not with TgAb positivity in the second trimester.
During the first trimester, TPOAb positivity (OR = 1.93; 95% CI, 1.17-3.18) and TgAb positivity (OR = 1.89; 95% CI, 1.15-3.11) were both associated with an increased risk for gestational hypertension compared with participants who were not positive, after adjustment for confounders. The risk for gestational hypertension was also increased with TPOAb positivity in the second trimester compared with no positivity (OR = 1.87; 95% CI, 1.02-3.43) after adjustment for confounders. No association was observed between TgAb positivity in the second trimester and risk for gestational hypertension or between autoantibody positivity and risk for preeclampsia.
“Thyroid autoantibodies (either TPOAb or TgAb) in the first trimester were associated with an increased risk for hypertensive disorders of pregnancy, and these associations were independent of thyroid dysfunction,” the researchers wrote. “Further studies are required to assess whether treatment of thyroid autoantibody positivity in pregnancy can reduce the risk for hypertensive disorders of pregnancy.” – by Amber Cox
Disclosures: The authors report no relevant financial disclosures.