Thyroid function in the third trimester of pregnancy and after delivery in an area of adequate iodine intake

Thyroid volume and nodular and diffuse thyroid diseases by ultrasonography in pregnant women: A case-control study

Background

Currently, it is shown that pregnancy may have an impact on the thyroid that can be leading to pregnancy complications such as abortion, preeclampsia, and preterm delivery. The objective was to compare the thyroid volume, number and characteristics of thyroid nodules, and prevalence of diffuse thyroid diseases in a sample of Iranian pregnant women in the first trimester to nonpregnant women.

Materials and Methods

This case-control study was conducted on 298 pregnant and 290 nonpregnant women. Thyroid volume, maximum diameter of thyroid nodules and prevalence of moderate to highly suspicious thyroid nodules, Hashimoto's appearance and goiter were assessed using thyroid ultrasonography. Antithyroperoxidase (TPO) antibodies were measured if the sonographic features were highly suggested for Hashimoto's thyroiditis.

Results

The mean of total thyroid volume in pregnant and nonpregnant women was 6 and 6.5 ml, respectively (P = 0.053), and the median (interquartile range) was 6.2 and 5.5, respectively. Nodules were observed in 16.4% of pregnant and 16.6% of nonpregnant women (P = 0.845). Hashimoto's thyroiditis was detected in 6.7% of pregnant and 12.4% of nonpregnant women (P = 0.013). Anti-TPO antibodies were detected in 5% of pregnant and 9.3% of nonpregnant women (P = 0.034).

Conclusion

The thyroid volume and nodule characteristics in the first trimester of pregnancy were similar to nonpregnant women. Hashimoto's thyroiditis and anti-TPO antibodies in pregnant women were significantly lower than in nonpregnant women.

Iron and Iodine Status in Pregnant Women from A Developing Country and Its Relation to Pregnancy Outcomes

Birth related complications and comorbidities are highly associated with a poor nutritional status of pregnant women, whereas iron and iodine are among especially important trace elements for healthy maternal and fetal outcomes. The study compares the status of iron, iodine, and related functional parameters in pregnant and non-pregnant women from a developing country and associates the data with pregnancy complications. The concentrations of ferritin, hemoglobin (Hb), total triiodothyronine (TT3), total thyroxine (TT4), and thyroid-stimulating hormone (TSH) were determined in the blood serum of 80 pregnant women at the time of delivery and compared with 40 non-pregnant healthy controls. Spot urine samples were taken to evaluate the urinary iodine concentration (UIC). In pregnant women, ferritin, Hb concentrations, and UIC were significantly lower, and TT4 values were significantly higher compared to controls. Higher Hb levels were tendentially associated with a reduced risk for pregnancy complications (OR = 0.747, CI (95%) 0.556–1.004; p = 0.053). Regarding covariates, only previous miscarriages were marginally associated with pregnancy complications. High consumption of dairy products was associated with lower Hb and ferritin values. Our results suggest that pregnant women from a developing country have lower iron status with Hb levels being possibly associated with pregnancy complications.

Variation of iodine status during pregnancy and its associations with thyroid function in women from Rio de Janeiro, Brazil

OBJECTIVE

To assess iodine status and its effects on maternal thyroid function throughout pregnancy.

DESIGN

In the present prospective cohort study, three urinary samples were requested for urinary iodine concentration (UIC) determinations in both the first and third gestational trimesters. Serum thyrotropin (TSH) and free thyroxine (FT4) were analysed in both trimesters and thyroid antibodies were assessed once.

SETTING

Rio de Janeiro, Brazil.ParticipantsFirst-trimester pregnant women (n 243), of whom 100 were re-evaluated during the third trimester.

RESULTS

Iodine sufficiency was found in the studied population (median UIC=216·7 µg/l). The first- and third-trimester median UIC was 221·0 and 208·0 µg/l, respectively. TSH levels (mean (sd)) were higher in the third trimester (1·08 (0·67) v. 1·67 (0·86) mIU/l; P<0·001), while FT4 levels decreased significantly (1·18 (0·16) v. 0·88 (0·12) ng/dl; P<0·001), regardless the presence of iodine deficiency (UIC<150 µg/l) or circulating thyroid antibodies. UIC correlated (β; 95% CI) independently and negatively with age (-0·43; -0·71, -0·17) and positively with multiparity (0·15; 0·02, 0·28) and BMI (0·25; 0·00, 0·50). Furthermore, median UIC per pregnant woman tended to correlate positively with TSH (0·07; -0·01, 0·14). Women with median UIC≥250 µg/l and at least one sample ≥500 µg/l throughout pregnancy had a higher risk of subclinical hypothyroidism (OR=6·6; 95% CI 1·2, 37·4).

CONCLUSIONS

In this cohort with adequate iodine status during pregnancy, excessive UIC was associated with an increased risk of subclinical hypothyroidism.

Epidemiological trends of iodine-related thyroid disorders: an example from Slovenia

The epidemiology of thyroid disorders is significantly associated with iodine supply. In 1999, Slovenia increased iodine content in kitchen salt from 10 mg to 25 mg of potassium iodide per kg of salt. According to the WHO criteria, Slovenia shifted from a mildly iodine-deficient country to a country with adequate iodine intake. Ten years after the increase in iodine intake, the incidence of diffuse goitre and thyroid autonomy decreased. Now patients with diffuse goitre and thyroid autonomy reach older age than the patients before the increase in iodine intake. In addition, patients with thyroid autonomy are less frequently hyperthyroid than ten years ago and iodine-induced hyperthyroidism is less severe. The incidence of highly malignant thyroid carcinoma has also dropped. However, the incidence of Hashimoto's thyroiditis increased, most probably in genetically predisposed individuals. Over the last ten years, many animal and in vitro studies evaluated the effects of endocrine disrupting chemicals (EDC) on various aspects of the thyroid function. They mostly studied the effects of polychlorinated biphenyls (PCBs) and dioxins, brominated flame retardants, phthalates, bisphenol A, perfluorinated chemicals, and perchlorate. However, human studies on the effects of EDCs on the thyroid function are very scarce, especially the long-term ones. What they do suggest is that PCBs and dioxins interfere with the transport of thyroid hormones and adversely affect the thyroid function. Many authors agree that iodine deficiency predisposes the thyroid gland to harmful effects of EDCs. Therefore the effects of EDCs in iodine-deficient areas could be more severe than in areas with adequate iodine intake.

Pregnancy Outcome in Euthyroid Women with Anti-Thyroid Peroxidase Antibodies

OBJECTIVE

The aim of this study was to compare pregnancy outcomes in euthyroid women who were anti-TPO Ab(+) with those who were anti-TPO Ab(-).

DESIGN

This observational study comprised 1,000 women in the age group of 25-35 years, having normal thyroid function tests, normotensive, non-diabetic, singleton pregnancy and attending Gyn. OPD/ANC up to 20 weeks' gestation and those who were already in the process of abortion. anti-TPO Ab levels of >50 IU/ml were considered as anti-TPO Ab(+).

SETTING

This study was conducted in the SMS Medical College's attached hospital, Jaipur from April 2012 to September 2013.

MAIN OUTCOME

The estimation of the proportion of anti-TPO Abs in the hospital-based population and the comparison of pregnancy and neonatal outcomes in anti-TPO Ab(+) and Ab(-) euthyroid women were done.

RESULTS

The main result showed increased rates in miscarriages (13.33 vs. 2.34 %, P < 0.001), LBWs (25 vs. 5.12 %, P < 0.001), preterm deliveries [<34 weeks] (5 vs. 1.80 %, P > 0.05) in anti-TPO Ab(+) women.

CONCLUSIONS

The current study revealed that anti-TPO Abs are strongly associated with miscarriage and LBW irrespective of their gestational age. However, we did not find any correlation with the other complication as found in the studies by Abbassi-Ghanavati, Negro et al.

Anti-thyroid peroxidase antibody positivity during early pregnancy is associated with pregnancy complications and maternal morbidity in later life

AIMS

We assessed the impact of detecting anti-thyroid peroxidase antibodies (anti-TPO-Ab) in the first trimester of pregnancy on pregnancy outcomes and maternal thyroid function during the postpartum period.

MATERIALS AND METHODS

In a prospective study consisting 400 pregnant women (8-12 weeks pregnant) were screened for their thyroid profile and followed-up to 12 weeks postpartum. Patients with abnormal thyroid function at 12 weeks postpartum were further followed-up with repeated assessment of thyroid stimulating hormone (TSH) and serum-free thyroxine-4 levels at 8 weeks interval up to 12 months postpartum.

RESULTS

11.5% of the subjects were positive for anti-TPO-Ab who had mean TSH level of 2.31 μIU/ml, which was significantly (P- 0.0001) higher than pregnant women negative for anti-TPO-Ab (1.73 μIU/ml). Increased incidence of miscarriage was observed in anti-TPO positive mothers when compared to antibody negative mothers. Postpartum thyroid dysfunction developed in 4.7% cases at 12 weeks, among them antibody positivity was observed in 81.25% of subjects. In 18.75% mothers positive for anti-TPO-Ab, the thyroid dysfunction persisted up to 12 months postpartum.

CONCLUSIONS

Thyroid antibodies detected in early pregnancy seems to be predicting pregnancy complications and later maternal thyroid disease related morbidity.

Alterations of thyroid volume and nodular size during and after pregnancy in a severe iodine-deficient area

OBJECTIVE

The effects of pregnancy on thyroid nodules were investigated in a few number of studies. We aimed to evaluate the prevalence of thyroid nodules, the changes in size, volume and number of nodules during pregnancy and after delivery in pregnant women.

DESIGN AND METHODS

This prospective study was performed in a severe iodine-deficient area and included 83 pregnant women (mean age 30·4 ± 5·5 years). We evaluated thyroid hormone levels, ultrasound examination of thyroid and urine iodine concentration (UIE) at each trimester and at 3-month post-partum period (PP). All patients with thyroid nodules >1 cm underwent fine-needle aspiration biopsy (FNAB) after the last visit at the PP.

RESULTS

Twenty-six women had thyroid nodules on thyroid ultrasonography at the first trimester. The volume of single/dominant nodule showed enlargement during pregnancy and remained at the PP; however, it was not significant (first trimester: 0·83 ± 0·8 ml; second trimester: 0·92 ± 1 ml; third trimester: 0·99 ± 1·2 ml; PP: 0·92 ± 1·2 ml). The maximum diameter of single/dominant nodule in the third trimester of pregnancy (12·6 ± 5·4 mm) was greater than the first trimester (11·9 ± 4·8 mm) (P = 0·002). The number of nodules did not change during pregnancy. The mean TV increased during pregnancy and remained 3 months after delivery (P < 0·001), and the maximum value of TV was reached in the third trimester (14·2 ± 7·9 ml). FNAB results revealed a 6·6% prevalence of malignancy among the nodules.

CONCLUSIONS

Thyroid nodules were present in 30·1% of pregnant women. While size of the single/dominant thyroid nodule increased significantly during pregnancy, the number of nodules did not change.

Urinary iodine and thyroid function in a population of healthy pregnant women in the North of Spain

BACKGROUND

Iodine is an essential trace element for the synthesis of thyroid hormones, which are keys in maternal metabolism during pregnancy as well as in neurological development during fetal and postnatal life. This was a prospective study on iodine status and thyroid function in women during pregnancy in the Basque country to assess whether there was any relationship among maternal urinary iodine, maternal thyroid function and thyrotropin (TSH) in newborns, and to explore any difference in women experiencing miscarriages.

METHODS

We analyzed TSH, free T(4) (FT(4)), free T(3) (FT(3)), thyroid peroxidase antibody (TPO-Ab) titers in serum and urinary iodine concentrations (UIC) in 2104 women in the first trimester of pregnancy and in 1322 of them in their second trimester. We obtained neonatal TSH levels in 1868 cases.

RESULTS

In the first (T1) and second trimesters (T2), the median UICs were 88.5 μg/L and 140 μg/L, respectively. No relationship was found between UIC and FT4, or maternal and neonatal TSH. In T1 and T2, 9.7% and 7.5% of women were TPO-Ab positive, respectively. The total miscarriage rate was 10%. The percentage of miscarriages in healthy women was 8.9%, lower than in women with overt hypothyroidism (21.2%; p < 0.001) and than in women with subclinical hypothyroidism (15.6%; p < 0.025). The miscarriage rate was not higher in TPO-Ab-positive women.

CONCLUSIONS

In this study most women had iodine deficiency during pregnancy. Neonatal TSH is not correlated with maternal UIC during pregnancy. Pregnant women with hypothyroidism have a higher rate of miscarriages.

Biological aspects of postpartum depression

In comparison with the vast epidemiological literature on postpartum depression (PPD), relatively few studies have examined the biological aspects of the disorder. However, research into the biological mechanisms of PPD is a challenging task, as normal pregnancy and the postpartum period cause adaptive endocrine changes, which would otherwise be considered pathological in nonpregnant women. This review focuses on the adaptive changes of childbearing and nursing, which ultimately may put women at increased risk of PPD. In light of the normal physiology, the authors also attempt to describe the current evidence of the biological changes associated with the development of depression in the postpartum period, including ovarian steroids, the hypothalamic-pituitary-adrenal axis, the serotonergic neurotransmitter system, the thyroid system and inflammatory markers. In addition, current knowledge on candidate genes associated with PPD is reviewed.

Iodine deficiency in northern Paris area: impact on fetal thyroid mensuration

Introduction

Iodine is essential for normal fetal and neonatal development. We studied the prevalence and impact on fetal thyroid development of iodine deficiency in pregnant women in the northern part of the Paris conurbation.

Materials and Methods

110 patients underwent several determinations of urinary iodine excretion (UIE) and of serum FT4, FT3, and TSH. Fetal thyroid gland size was assessed using ultrasonography.

Results

We found evidence of widespread iodine deficiency (mean UIE, 49.8 µg/L [standard deviation, 2.11]). Iodine deficiency did not correlate significantly with maternal thyroid parameters but showed a significant negative correlation with fetal thyroid gland size (rho = 0.25, P = 0.02).

Conclusion

Iodine deficiency during pregnancy is still a problem in our geographical area and affects the fetal thyroid gland.

Clinical Trials.gov NCT00162539