In this study, TPOAb positivity was not associated with a higher risk of preterm birth except when the sex of the fetus was considered; in particular, TPOAb positivity in women with a female fetus was associated with preterm birth. not associated with an increased risk of poor pregnancy or fetal outcomes in euthyroid women. However, TPOAb-positive euthyroid women pregnant with a female fetus were independently associated with preterm births (OR: 4.511, 95% CI: 1.07518.926) after adjustment for potential confounding factors. == Conclusions == TPOAb positivity was not found to be associated with poor pregnancy-related or fetal outcomes in euthyroid women. However, in euthyroid women with a female fetus, TPOAb positivity was strongly associated with preterm births. The risk of preterm birth in the euthyroid women with TPOAb positivity should be emphasized in clinical practice. == Trial registration == ClinicalTrials.govIdentifier:NCT02966405. Registered on October 24th 2016 – Retrospectively registered. Keywords:Thyroid peroxidase antibodies, Euthyroid, Pregnancy and fetal outcomes == Background == Recent studies have reported that thyroid autoimmunity (TAI) and subclinical CarbinoxaMine Maleate hypothyroidism (SCH) are associated with an increased Rabbit Polyclonal to CDC7 risk of poor pregnancy and fetal outcomes, such as spontaneous abortion, preterm birth, and lower offspring motor and intelligence quotients [1,2]. TAI is characterized by anti-thyroid peroxidase antibody (TPOAb) and/or thyroglobulin antibody (TGAb) positivity. Guidelines published by the American Thyroid Association (ATA) in 2017 [3] recommended establishing population-based trimester-specific reference ranges for serum thyroid-stimulating hormone (TSH) levels. If information is unavailable, the recommended upper normal limit cutoff for TSH is 4.0 mU/L. Meanwhile, 2.5 mU/L can be used as the cutoff for SCH combined with TPOAb positivity. Levothyroxine CarbinoxaMine Maleate (LT4) replacement therapy may be considered for TPOAb-positive women with TSH concentrations > 2.5 mU/L and below the upper limit of the pregnancy-specific reference range [3]. However, whether TPOAb positivity is associated with poor pregnancy and fetal outcomes in euthyroid women is debatable. It is known that the prevalence of TPOAb varies with ethnicity, gender, and iodine intake [35]. A recent meta-analysis [6] showed the presence of TAI was associated with an increased risk of spontaneous miscarriage. A separate meta-analysis [7] found TPOAb-positive women had a higher risk of preterm birth than TPOAb-negative women. Several studies have examined the associations between maternal TAI and child autism spectrum [8] and lower motor and intellectual development [9]. TPOAb positivity has been associated with poor pregnancy and fetal outcomes in euthyroid women in some but not all studies [10,11]. Therefore, the aim of the present study was to investigate the impact of TPOAb positivity on the pregnancy-related and fetal outcomes in euthyroid women. == Methods == == Study population == This was a prospective cohort study conducted at a single site. The inclusion criteria were (a) single birth; (b) fetus at 48 weeks gestation diagnosed by last menstrual period and human chorionic gonadotropin (HCG); (c) euthyroid women (TSH > 0.12 and 2.5 uIU/mL) in the first trimester of pregnancy. The exclusion criteria were (a) diagnosis of hereditary disease, tumors, autoimmune disease (e.g., systemic lupus erythematosus, Sjogren syndrome, or antiphospholipid antibody syndrome), heart disease, liver disease, renal disease, or chronic hypertension; (b) consumption of medication that could affect thyroid function. In total, 1428 pregnant women who presented at the Department of Gynaecology and Obstetrics of Peking University International Hospital volunteered to participate in this study from October 2016 to April 2018. In total, twenty six women with twin pregnancies, 38 pregnant women with subclinical hyperthyroidism or hyperthyroidism, 223 pregnant women with a TSH concentration of > 2.5 and 4.16 uIU/mL, and normal FT4, 105 pregnant women with SCH or hypothyroidism, 24 pregnant women with hypothyroxinemia, 59 euthyroid women with only CarbinoxaMine Maleate TGAb positivity, and 15 pregnant women with other thyroid dysfunctions were excluded. Ultimately, 938 subjects participated in this study. The euthyroid group included 837 pregnant women with a TSH concentration of > 0.12 and 2.5 uIU/mL, normal FT4, and TPOAb and TGAb negativity. The TPOAb-positive group included 101 TPOAb-positive with or without TGAb positivity euthyroid women (Fig.1). Written informed consents were obtained from all study participants. This study was registered onClinicalTrials.gov(Identifier:NCT02966405). == Fig. 1. == Flow chart of patient selection. TSH, thyroid-stimulating hormone; FT4, free thyroxine; SCH, subclinical hypothyroidism; TGAb, thyroglobulin antibody; TPOAb, thyroid peroxidase antibody All pregnant women completed the questionnaire about the history of thyroid or autoimmune disease, family health history of thyroid disorders, and previous abortion. The height, weight, blood pressure, and gestational age of the participants were recorded. The body-mass index (BMI) was calculated as weight in kilograms divided by height in meters squared. The serum blood glucose (GS), glycosylated hemoglobin (HbA1c), low-density.