Thyroid peroxidase antibodies in Mexican-born healthy pregnant women, in women with type 2 or gestational diabetes mellitus, and in their offspring

Association of Thyroid Function During Pregnancy With the Risk of Pre-eclampsia and Gestational Diabetes Mellitus

OBJECTIVE

To estimate the association of maternal thyroid dysfunction with the risk of gestational hypertension and diabetes. Whether the association was affected by gestational age at diagnosis and thyroid autoimmunity was further explored.

METHODS

A cohort study of 41 647 participants was conducted. Thyroid function (ie, thyroid-stimulating hormone [TSH] and free thyroxine [FT4]) was measured by electrochemiluminescence immunoassay. Thyroid antibody positivity (eg, thyroperoxidase, thyroglobulin, and TSH receptor antibody) was indicated if the values of these antibodies exceeded the upper targets of the reference range. The relationship between maternal thyroid dysfunction and the risk of pre-eclampsia (PE) and gestational diabetes mellitus (GDM) was assessed by multivariate logistic regression.

RESULTS

Isolated hypothyroxinemia (defined as 5th ≤ TSH ≤ 95th percentile, FT4 < 5th percentile) was associated with the risk of PE (odds ratio [OR], 1.32; 95% CI, 1.10-1.58). Overt hypothyroidism (TSH > 95th percentile; FT4 < 5th percentile) was related to the risk of severe PE (OR, 2.59; 95% CI, 1.05-6.37). Being positive for TSH receptor antibody was associated with a decreased risk of GDM (OR, 0.49; 95% CI, 0.35-0.70). A marginally significant association between overt hypothyroidism detected at the first trimester and the risk of GDM was found (OR, 1.60; 95% CI, 1.00-2.83). The association of thyroid dysfunction with the risk of PE and GDM was stronger among pregnant women who were negative for autoantibodies.

CONCLUSION

Some types of thyroid dysfunction during pregnancy were associated with the risk of PE and GDM. The associations varied by gestational age at diagnosis and by thyroid autoantibody status.

The Presence of Thyroid Peroxidase Antibody Is Associated with Lower Placental Weight in Maternal Thyroid Dysfunction

Thyroid dysfunction (TD) is caused by thyroid peroxidase (TPO) antibody, as seen in Hashimoto's disease. TD is a common problem of reproductive age and may impair fetal development. Here, we determined the effect of TPO antibody on perinatal outcomes in Japanese women with TD before conception. A retrospective study involving cases of maternal TD with term singleton birth was conducted. The subjects with TD were divided into two groups according to the presence (n = 22) or absence (n = 20) of TPO antibody. The control groups matched for age, parity, and gestational weeks were selected for TPO antibody-positive (n = 44) and -negative TD subjects (n = 40), respectively. Using the standard curve of Japanese placental weight, the frequency of placental weight less than the 50th percentile (small placenta) was examined. Placental weight was lower among TPO antibody-positive TD subjects, compared with TPO antibody-negative TD subjects (p < 0.01). However, other outcomes were similar between the groups. Importantly, compared with control mothers, placental weight was significantly lower (p < 0.01), birth weight tended to be lower (p = 0.07), and the incidence of gestational diabetes mellitus was higher (p = 0.02) among TPO antibody-positive subjects. There was no significant difference in placental weight between TPO antibody-negative subjects and controls. The frequency of small placenta was significantly higher in TPO antibody-positive subjects (odds ratio: 16.7) even when considering diabetes and pregnancy induced hypertension. Thus, the presence of TPO antibody is associated with lower placental weight among Japanese women having TD.

Isolated effect of maternal thyroid-stimulating hormone, free thyroxine and antithyroid peroxidase antibodies in early pregnancy on gestational diabetes mellitus: a birth cohort study in China

This article aims to understand the isolated effect of maternal thyroid-stimulating hormone (TSH), free thyroxine (FT₄) and antithyroid peroxidase antibodies (TPOAb) in early pregnancy on gestational diabetes mellitus (GDM). Based on a birth cohort, pregnant women presented to maternity hospitals for the first antenatal care from Nov 2008 to Oct 2010 were invited to participate in the study. A self-administered questionnaire was asked to complete to collect data on socio-economic variables, previous adverse pregnancy outcomes, method of conception, previous endocrinic and metabolic diseases, and pregnancy-related anxiety in 1^st trimester of the index pregnancy. Pre-pregnancy BMI was measured. Serum samples were collected, and TSH, FT₄ and TPOAb were assayed. GDM was confirmed from medical records screened on 24-28 gestational weeks by using oral glucose tolerance test (OGTT). The prevalence of isolated subclinical hypothyroidism, hypothyroidemia and positive TPOAb in early pregnancy was 2.0%, 2.0% and 12.8%. Prevalence of GDM in women with the isolated sub-clinical hypothyroidism, hypothyroxinemia and positive TPOAb was 2.9%, 2.8% and 3.1%, respectively, which were all higher than that detected in euthyroidism women (1.2%). Women with isolated positive TPOAb had significantly higher TSH and lower FT₄ level compared with euthyroidism women. It was found that isolated positive TPOAb in early pregnancy increased the risk of GDM, adjusted RR and 95%CI being 2.541(1.037-6.226). No significant relationships were identified between isolated sub-clinical hypothyroidism or hypothyroxinemia with GDM. In conclusion, isolated thyroid autoimmunity, represented by positive TPOAb, in early pregnancy were associated with GDM independent of TSH and FT₄.

Maternal TSH level and TPOAb status in early pregnancy and their relationship to the risk of gestational diabetes mellitus

Subclinical hypothyroidism is common in pregnant women and often related to adverse pregnancy outcomes, but its relationship with gestational diabetes remains controversial. In particular, the impact of thyroperoxidase antibodies status on the relationship between subclinical hypothyroidism and gestational diabetes is not clear. We investigated the association between combined thyroid stimulating hormone (TSH) level and thyroperoxidase antibodies status in early pregnancy (<20 weeks of gestation) and gestational diabetes mellitus. A total of 7084 pregnant women met the inclusion criteria, which included thyroperoxidase antibodies-positive subclinical hypothyroidism [TSH(H)TPOAb(+)] (n = 78), thyroperoxidase antibodies-negative subclinical hypothyroidism [TSH(H)TPOAb(-)] (n = 281), thyroperoxidase antibodies-positive euthyroidism [TSH(N)TPOAb(+)] (n = 648), and thyroperoxidase antibodies-negative euthyroidism [TSH(N)TPOAb(-)] (n = 6077). Of the 7084 cases included in our study, 1141 cases were diagnosed with gestational diabetes mellitus at 24-28 weeks of pregnancy. The prevalence of gestational diabetes mellitus in TSH(N)TPOAb(-), TSH(H)TPOAb(-), TSH(N)TPOAb(+), and TSH(H)TPOAb(+) was 14.65, 19.57, 24.85, and 46.15 %, respectively. Compared with TSH(N)TPOAb(-) women, the risk of gestational diabetes mellitus was increased in all other groups of women in early pregnancy. After dividing early pregnancy into first and second trimesters, we found that TSH(H)TPOAb(-) women in the first trimester do not show this increase. Our study suggests that subclinical hypothyroidism and thyroperoxidase antibodies-positive euthyroidism in early pregnancy are associated with an increased risk of gestational diabetes mellitus.

Thyroid antibodies and gestational diabetes mellitus: a meta-analysis

OBJECTIVE

To determine whether thyroid antibodies are associated with an increased risk of gestational diabetes mellitus (GDM) in pregnant women.

DESIGN

Meta-analysis.

SETTING

Not applicable.

PATIENT(S)

Twenty cohort and case-control studies involving pregnant women with positive thyroid antibodies were the exposure of interest, and GDM was the outcome.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

A fixed-effects model was used to evaluate the relationship between thyroid antibodies and the risk of GDM. Subgroup analyses were performed among different types of study design, different thyroid antibodies, and patients with specific thyroid dysfunction.

RESULT(S)

The search strategy identified 167 potentially relevant publications, of which 20 were included in the meta-analysis. A significant association between thyroid antibodies and GDM was observed. A meta-analysis of the 11 cohort studies with pregnant women with positive thyroid antibodies in their first trimester suggested no obvious risk of GDM compared with the reference group. In subgroup meta-analyses, no significant association between thyroid antibodies and GDM was found in euthyroid pregnant women, whereas a significant positive association was identified in women with a thyroid dysfunction.

CONCLUSION(S)

Based on the currently available evidence, there is a significant but not strong association between thyroid antibodies and the risk of GDM, and thyroid antibodies in the first trimester lack predictive value for the risk of GDM. In addition, thyroid antibodies may not increase the risk of GDM in euthyroid pregnant women.

Anti thyroperoxidase and anti thyroglobulin antibodies in diabetic pregnancies

INTRODUCTION

Thyroid autoimmunity is very frequent in women of reproductive age and is associated with many adverse pregnancy outcomes; also, diabetes mellitus in pregnancy, of any type, is associated to many complications. In type 1 diabetes, the prevalence of thyroid autoimmunity is higher than in healthy population. Instead, the association of thyroid autoimmunity with other types of diabetes is less clear; however, there are some studies claiming that the prevalence is higher in gestational diabetes too. Poor data about type 2 diabetes in pregnancy are available. It is also unclear how diabetes and thyroid function influence each other and if levothyroxine therapy is necessary in pregnancy with positive autoimmunity but normal thyroid function.

MATERIALS AND METHODS

The aim of this article was to find in the literature studies on thyroid autoimmunity in different types of diabetes in pregnancy, in order to detect any difference in prevalence. Data were found through pubmed database from 1990 to 2013.

CONCLUSIONS

Several studies found a higher prevalence of thyroid autoimmunity in GDM compared to healthy controls; therefore it would be appropriate to extend screening for thyroid diseases to women with GDM. More studies are needed on the possible requirement of therapy for thyroid autoimmunity when the function is normal.

Evaluation of thyroid dysfunction in pregnant women with gestational and pre-gestational diabetes

Objective: The aim of this study was to investigate thyroid function tests in Gestational Diabetes Mellitus (GDM) and pre-gestational DM and control group.

Methodology: There were 61 pregnant diabetic women in study group and 35 pregnant women in control group. Serum T4, T3, T3RU, FTI, TSH and Anti TPO Ab were assessed in each person.

Results: About 36% of patients had GDM and 64% pre-gestational DM. Thyroid dysfunction was detected in 18% of study group compared with 8.6% of control group (P = 0.2). There was Thyroid dysfunction in 4.5% of GDM and 25.6% of pregestational DM (P = 0.045). There was no statistically significant difference between thyroid dysfunction in GDM group and control group (P=0.99).27% of GDM and 36% of pregestational DM and 23% of control group had positive titer of Anti TPO Ab without statistically significant differences among the three groups.

Conclusion: Thyroid dysfunction is prevalent in women with pre-gestational DM so, thyroid function should be evaluated in these patients during pregnancy. Rate of thyroid dysfunction in GDM patients is similar to normal pregnant control women. High prevalence of positive titer of TPO Ab was seen in diabetic and non-diabetic pregnant women.

Gestational diabetes and thyroid autoimmunity

Background. About 10% of pregnancies are complicated by previously unknown impairment of glucose metabolism, which is defined as gestational diabetes. There are little data available on prevalence of thyroid disorders in patients affected by gestational diabetes, and about their postgestational thyroid function and autoimmunity. We therefore investigated pancreatic and thyroid autoimmunity in gestational diabetic patients and in women who had had a previous gestational diabetic pregnancy. Methods. We investigated 126 pregnant women at the time of a 100-g oral glucose tolerance test: 91 were classified as gestational diabetics, and 35 were negative (controls). We also studied 69 women who had delivered a baby 18-120 months prior to this investigation and who were classified at that time gestational diabetics (38 women) or normally pregnant (31 women; controls). Results. Our data show no differences for both thyroid function and prevalence of autoimmune disorders during pregnancy; however, a significant increase in thyroid autoimmunity was seen in women previously affected by gestational diabetes. This increased prevalence of thyroid autoimmunity was not associated with the development of impaired glucose metabolism after pregnancy. Conclusions. Our data suggest that maternal hyperglycemia is a risk factor for the development of thyroid autoimmunity, a conclusion that should now be confirmed in a larger cohort of patients.

Thyroid function abnormalities and antithyroid antibody prevalence in pregnant women at high risk for gestational diabetes mellitus

Both gestational diabetes mellitus (GDM) and thyroid dysfunction in pregnancy compromise maternal and fetal health. The aim of the present study was to determine the prevalence of abnormal thyroid function and antithyroid antibodies during early pregnancy in a population at high risk for GDM. Serum free triiodothyronine (FT3), free thyroxine (FT4) and thyroid-stimulating hormone (TSH) were measured in 301 pregnant women who underwent routine 'universal screening' for GDM. The antithyroid peroxidase antibody (antiTPOAb) was also quantified in 255 of these women. GDM was confirmed by a 75-g oral glucose tolerance test using World Health Organization criteria. No statistically significant difference was found between the 80 (26.6%) women with GDM and the 221 (73.4%) women without GDM for any of the thyroid function tests. In the cohort tested for antiTPOAb, the 51 (20.0%) women who were positive for antiTPOAb had higher mean TSH (1.57 +/- 2.49 mIU/l; p < 0.001) than the women negative for antiTPOAb. Seventeen (5.6%) women had low FT4 while 12 (4.0%) women had high TSH; 28 (9.3%) women had low serum TSH, among whom three (1.0%) also had high FT4. The significantly higher prevalence of hypothyroxinemia and antiTPOAb titers than generally reported warrants routine screening for thyroid abnormalities. This screening, which can be effectively and easily incorporated into screening practices already in place for GDM, would result in improved obstetric care.