Iodine deficiency in pregnancy along a concentration gradient is associated with increased severity of preeclampsia in rural Eastern Cape, South Africa

Iodine Status, Thyroid Disorder and Feto-Maternal Outcome among the Tribal Pregnant Women of Eastern Himalayas

Introduction

Iodine deficiency and thyroid disorder during pregnancy have adverse effects on fetal and neonatal outcomes.

Objective

To assess iodine status and thyroid functioning during pregnancy and to evaluate the feto-maternal outcome.

Methods

Urinary iodine content (UIC) is determined by arsenic cerium catalytic spectrophotometry method and thyroid hormone analysis was carried out by chemiluminescence assay. Fetal and neonatal outcomes were obtained from hospital records.

Results

Among the considered tribal pregnant women 56.75% had insufficient urinary iodine and 24.5% had a thyroid disorder. Thyroid disorder was more common in pregnant women with urinary iodine concentration (UIC) <99 μg/L than UIC >150 μg/L (56.75% vs 41.5%). Pregnant women with UIC<99 μg/L had a higher incidence of anemia (86.36%), gestational diabetes mellitus (GDM) (3.33%), and preeclampsia (5.71%) than UIC >150 μg/L. The fetal outcome with UIC <99 μg/L had a higher incidence of low birth weight (9.09%) and preterm births (1.9%). Stillbirths were distributed equally among different UIC groups. The neonatal outcomes with UIC <99 μg/L between 150-249 μg/L had a higher incidence of respiratory distress (5.23%). Hypothermia was equally distributed among different UIC groups. Subclinical hypothyroid had a high prevalence of anemia (62.96%), preeclampsia (3.7%), and GDM (6.17%) respectively than the euthyroid group. The fetal outcome with low birth weight (LBW) (9.87%), stillbirths (3.7%), and preterm birth (8.64%) was more common in the subclinical hypothyroid than in the euthyroid group. Among the neonatal outcomes respiratory distress (6.17%) and hypothermia (4.93%) were more common in subclinical hypothyroid than euthyroid pregnant women.

Conclusion

Insufficient maternal iodine and thyroid disorders during pregnancy were associated with adverse pregnancy outcomes.

Iodine nutrition level and thyroid function in pregnant women in the Yongchuan district of Chongqing

BACKGROUND AND AIM

This study aims to investigate thyroid function-associated parameters and the incidence of thyroid disorders in pregnant women, with the overarching aim to ensure that pregnant women do not develop said disorders due to aberrant iodine levels during the course of pregnancy.

METHODS

A total of 300 pregnant women who underwent routine check-ups at the Yongchuan Hospital Affiliated to Chongqing Medical University from January to December 2021 were enrolled. Venous blood and morning urine were collected. Serum thyroid-stimulating hormone (TSH), free thyroxine (FT4), and free triiodothyronine (FT3) were determined by chemiluminescence immunoassay. Urinary iodine concentration (UIC) was detected by arsenic cerium catalytic spectrophotometry. Thyroid disorders were extrapolated from the measured parameters.

RESULTS

The overall median UIC was 203 μg/L, which was within normal range. Subgroup analysis revealed that the median UIC in the first trimester was 187.5 μg/L, 211.8 μg/L in the second trimester, and 239.9 μg/L in the third trimester. However, based on the WHO criteria, 32%, 30%, and 18% of pregnant women were iodine deficient during their first, second, and third trimester, respectively. The proportion of women with iodine deficiency in the first and second trimesters was higher compared to the third trimester (P < 0.05). Serum FT3 and FT4 concentrations were higher in subjects in their first and second trimester versus the third trimester, while serum TSH levels were lower in subjects in their first and second trimester versus the third trimester (P < 0.05). The TSH concentration in subjects with inadequate iodine intake (UIC < 150 μg/L) was lower compared to subjects with adequate iodine intake (UIC 150 - 249 μg/L), but higher than in subjects with more than adequate intake (UIC 250 - 499 μg/L) and excess iodine intake (UIC ≥ 500 μg/L) (P < 0.05). TSH concentration and UIC were positively correlated (r = 0.1945, P = 0.0007), while no relationship was observed between UIC and FT3 and FT4 serum levels (r₁ = -0.0593, P₁ = 0.3053; r₂ = -0.0149, P₂ = 0.7968). There was no significant difference in FT3 and FT4 concentration between different UIC strata (P > 0.05). The incidence of thyroid disease during pregnancy in iodine-deficient women was greater compared to pregnant women with adequate iodine intake (P < 0.05) and higher in subjects in the more than adequate as well as excessive iodine intake cohorts (P < 0.05).

CONCLUSION

The iodine nutritional intake by pregnant women in Yongchuan District, Chongqing, was generally sufficient to meet developmental and metabolic needs. However, about a third of women in their first and second trimester exhibited iodine deficiency. Iodine deficiency was associated with an increased incidence of thyroid diseases.

RELEVANCE FOR PATIENTS

In clinical practice, the UIC of pregnant women should be measured during key stages in the pregnancy to prevent the manifestation of thyroid diseases.

Histological and hemodynamic characterization of corpus luteum throughout the luteal phase in pregnant and non-pregnant buffalos in relation to nitric oxide levels based on its anatomical determination

This study aims to compare the complete growth and development of corpus luteum (CL) in domestic buffalos from day 5 until day 40 after ovulation either in pregnant or non-pregnant animals and whether luteal vascularity (LV) with progesterone (P4) and nitric oxide (NO) could determine luteal functionality or not. Pluriparous buffalos (Bubalus bubalis) were categorized as pregnant (n = 6) or non-pregnant (n = 9) after pregnancy check at day 25. Animals were subjected to ultrasound analysis to determine the CL area (cm²) and LV. Blood sampling was performed following the Doppler examination. Ovarian tissue samples from non-pregnant buffalo genitalia (n = 18) and early pregnant buffalo genitalia (n = 3) were collected from great abattoirs. Luteal Doppler indices were lower in the pregnant group, while peak systolic velocity (PSV) was increased (p < 0.05) in the same pregnant females. Both P4 and NOMs were elevated (p < 0.05) in the pregnant group. There was a positive correlation (p < 0.01) between P4 and CL PSV. Based on our macroscopical examination, the CL of non-pregnant buffalos was classified into four stages. Histologically, stage I showed that CL was covered by a highly vascularized connective tissue (CT) capsule. It consisted of small and large lutein cells, whereas stage II was similar to stage I except for the presence of numerous fibroblast cells and vacuolated cells. Stage III was characterized by increasing the number of collagen fibers and the thickness of the blood vessels. Stage IV revealed thickening of the CT capsule and septae, regressed capillaries and arterioles, in addition to shrunken degenerated lutein cells. CL of pregnant buffalos revealed the same structure as CL at stage II. CL area was increased in the pregnant group. The collective data suggested that evaluation of the luteal artery could be extremely helpful to determine the potential benefits of colored and pulsed Doppler in CL vascularization assessment in both luteal and early pregnancy phases.