Thyroid Function and Premature Delivery in TPO Antibody-Negative Women: The Added Value of hCG.

Human chorionic gonadotropin (hCG) stimulates thyroid function during pregnancy. We recently showed that thyroid autoimmunity severely attenuated the thyroidal response to hCG stimulation and that this may underlie the higher risk of premature delivery in thyroperoxidase antibody (TPOAb)-positive women. We hypothesized that a lower thyroidal response to hCG stimulation in TPOAb-negative women is also associated with a higher risk of premature delivery and preterm premature rupture of membranes (pPROM). Thyrotropin (TSH), free thyroxine (FT4), and hCG concentrations were available in 5644 TPOAb-negative women from a prospective cohort. We tested for interaction between TSH or FT4 and hCG in linear regression models for duration of pregnancy and logistic regression models for premature delivery/pPROM. Accordingly, analyses were stratified per TSH percentile (TSH ≥ 85th percentile) and hCG per 10,000 IU/L. Women with high TSH and low hCG concentrations did not have a higher risk of premature delivery or pPROM, with protective effect estimates. In contrast, women with a high TSH concentration despite a high hCG concentration had twofold to 10-fold higher risk of premature delivery (Pdifference = 0.022) and an up to fourfold higher risk of pPROM (Pdifference = 0.079). hCG concentrations were not associated with premature delivery or pPROM. In TPOAb-negative women with high-normal TSH concentrations, only women with high hCG concentrations had a higher risk of premature delivery or pPROM. These results suggest a lower thyroidal response to hCG stimulation is also associated with premature delivery in TPOAb-negative women and that an additional measurement of hCG may improve thyroid-related risk assessments during pregnancy.

Korevaar TIM ，Steegers EAP ，Chaker L ，Medici M ，Jaddoe VWV ，Visser TJ ，de Rijke YB ，Peeters RP ... -  《-》

Thyroid Autoimmunity Impairs the Thyroidal Response to Human Chorionic Gonadotropin: Two Population-Based Prospective Cohort Studies.

Thyroperoxidase antibody (TPOAb) positivity is the main risk factor for thyroid dysfunction during pregnancy and is consistently associated with premature delivery. However, the underlying mechanism is currently unknown. We hypothesized that TPOAb positivity may interfere with gestational thyroid stimulation induced by the pregnancy hormone human chorionic gonadotropin (hCG). Thyrotropin (TSH), free thyroxine (FT4), TPOAbs, and/or hCG concentrations were measured in early and late pregnancy of 7587 pregnant women from 2 Dutch population-based prospective cohorts (n = 5924, Generation R study; n = 1663, Holistic Approach to Pregnancy and the First Postpartum Year study). None. Thyroidal response to hCG stimulation, premature delivery. In TPOAb-negative women, hCG was positively associated with FT4 and negatively with TSH in both cohorts (P < 0.0001). In contrast, in TPOAb-positive women, hCG was not associated with FT4 or TSH in either cohort (all P > 0.40; P for interaction TPOAb positive vs negative ≤ 0.05). Overall, TPOAb positivity was associated with a 1.7-fold higher risk of premature delivery. TPOAb-positive women with an adequate response of FT4 to hCG (high FT4 concentration with high hCG concentration) did not have a higher risk of premature delivery. In contrast, TPOAb-positive women with an inadequate FT4 response to hCG (low FT4 concentration with high hCG concentration) had a 2.2- to 2.8-fold higher risk of premature delivery. TPOAb-positive women display an impaired thyroidal response to hCG and this may explain the higher risk of premature delivery in these women. This abnormal response in TPOAb-positive women might suggest that these women require a different treatment approach than TPOAb-negative women.

Korevaar TI ，Steegers EA ，Pop VJ ，Broeren MA ，Chaker L ，de Rijke YB ，Jaddoe VW ，Medici M ，Visser TJ ，Tiemeier H ，Peeters RP ... -  《-》

Different Thyroidal Responses to Human Chorionic Gonadotropin Under Different Thyroid Peroxidase Antibody and/or Thyroglobulin Antibody Positivity Conditions During the First Half of Pregnancy.

Hou Y ，Liu A ，Li J ，Wang H ，Yang Y ，Li Y ，Fan C ，Zhang H ，Wang H ，Ding S ，Teng W ，Shan Z ... -  《-》

Dose Dependency and a Functional Cutoff for TPO-Antibody Positivity During Pregnancy.

To investigate a dose dependency of thyroperoxidase antibody (TPOAb) concentrations in relation to thyroid function and premature delivery and define a population-based, pregnancy-specific, functional cutoff for TPOAb positivity. Individual participant meta-analysis of three prospective birth cohorts: the Amsterdam Born Children and their Development study, and the Holistic Approach to Pregnancy. Population-based studies in the Netherlands (2002 to 2014). A total of 11,212 pregnant women (<20 weeks' gestation). Thyrotropin (TSH) and FT4 concentrations, premature delivery. In all cohorts, there was a dose-dependent positive association of TPOAb concentrations with TSH concentrations, as well as a dose-dependent negative association with FT4 concentrations during early pregnancy (all P < 0.0001). There was a dose-dependent association of TPOAb concentrations with the risk of premature delivery, which was also modified by TSH concentrations. Women with TPOAb concentrations from the 92nd percentile upward had a higher TSH and a higher risk of a TSH >2.5 mU/L (range, 19.4% to 51.3%). Stratified analyses showed that women with TPOAb concentrations below manufacturer cutoffs already had a higher risk of premature delivery, especially when TSH concentrations were high or in the high-normal range. This study demonstrated a dose-dependent relationship between TPOAbs and thyroid function as well as the risk of premature delivery. Furthermore, our results indicate that the currently used cutoffs for TPOAb positivity may be too high. Furthermore, the use of a population-based cutoff for TPOAbs may identify women with a clinically relevant extent of thyroid autoimmunity and a higher risk of premature delivery but that would not be considered TPOAb positive or eligible for treatment otherwise.

Korevaar TIM ，Pop VJ ，Chaker L ，Goddijn M ，de Rijke YB ，Bisschop PH ，Broeren MA ，Jaddoe VWV ，Medici M ，Visser TJ ，Steegers EAP ，Vrijkotte TG ，Peeters RP ... -  《-》

The Risk of Preeclampsia According to High Thyroid Function in Pregnancy Differs by hCG Concentration.

Korevaar TI ，Steegers EA ，Chaker L ，Medici M ，Jaddoe VW ，Visser TJ ，de Rijke YB ，Peeters RP ... -  《-》