Iodization and thyroid status in relation to stillbirths and congenital anomalies

Iodine and thyroid status during pregnancy and risk of stillbirth: A population-based nested case-control study

Prior research suggests that severe iodine deficiency in pregnancy may be associated with stillbirth. However, the relationship between mild to moderate iodine insufficiency, which is prevalent even in developed countries, and risk of stillbirth is unclear. We thus examined associations of iodine status and risk of stillbirth in a prospective population‐based nested case–control study in Finland, a mild to moderately iodine insufficient population. Stillbirth cases (n = 199) and unaffected controls (n = 249) were randomly selected from among all singleton births in Finland from 2012 to 2013. Serum samples were collected between 10 and 14 weeks gestation and analysed for iodide, thyroglobulin (Tg) and thyroid‐stimulating hormone (TSH). Odds ratios (ORs) and 95% confidence intervals (CIs) for stillbirth were estimated using logistic regression. After adjusting for maternal age, prepregnancy body mass index, socio‐economic status and other factors, neither high nor low serum iodide was associated with risk of stillbirth (Q1 vs. Q2–Q3 OR = 0.92, 95% CI = 0.78–1.09; Q4 vs. Q2–Q3 OR = 0.78; 95% CI = 0.45–1.33). Tg and TSH were also not associated with risk of stillbirth in adjusted models. Maternal iodine status was not associated with stillbirth risk in this mildly to moderately iodine‐deficient population. Tg and TSH, which reflect functional iodine status, were also not associated with stillbirth risk. The lack of associations observed between serum iodide, TSH and Tg and risk of stillbirth is reassuring, given that iodine deficiency in pregnancy is prevalent in developed countries.

Pregnancy Loss and Iodine Status: The LIFE Prospective Cohort Study

Iodine deficiency in pregnancy is a common problem in the United States and parts of Europe, but whether iodine deficiency is associated with increased pregnancy loss has not been well studied. The LIFE study provided an excellent opportunity to examine the relationship between iodine status and pregnancy loss because women were monitored prospectively to ensure excellent ascertainment of conceptions. The LIFE study, a population-based prospective cohort study, monitored 501 women who had discontinued contraception within two months to become pregnant; 329 became pregnant, had urinary iodine concentrations measured on samples collected at enrollment, and were followed up to determine pregnancy outcomes. Of the 329, 196 had live births (59.5%), 92 (28.0%) had losses, and 41 (12.5%) withdrew or were lost to follow up. Urinary iodine concentrations were in the deficiency range in 59.6% of the participants. The risk of loss, however, was not elevated in the mildly deficient group (hazard ratio 0.69, 95% confidence interval 0.34, 1.38), the moderately deficient group (hazard ratio 0.81, 95% confidence interval 0.43, 1.51), or the severely deficient group (hazard ratio 0.69, 95% confidence interval 0.32, 1.50). Iodine deficiency, even when moderate to severe, was not associated with increased rates of pregnancy loss. This study provides some reassurance that iodine deficiency at levels seen in many developed countries does not increase the risk of pregnancy loss.

Birth defects in India: Hidden truth, need for urgent attention

Birth defects (structural, functional and metabolic disorder present from birth, may be diagnosed later) rising up as an important cause of infant mortality even in developing countries where infant mortality has been reduced to much extent. Seventy percent of birth defects are preventable through the application of various cost effective community genetic services.

Indian people are living in the midst of risk factors for birth defects, e.g., universality of marriage, high fertility, large number of unplanned pregnancies, poor coverage of antenatal care, poor maternal nutritional status, high consanguineous marriages rate, and high carrier rate for hemoglobinopathies. India being the second most populous country with a large number infant born annually with birth defects should focus its attention on strategies for control of birth defects. Many population based strategies such as iodization, double fortification of salt, flour fortification with multivitamins, folic acid supplementation, periconceptional care, carrier screening and prenatal screening are some of proven strategies for control of birth defects. Strategies such as iodization of salt in spite of being initiated for a long time in the past do have a very little impact on its consumption (only 50% were using iodized salt). Community genetic services for control of birth defects can be easily flourished and integrated with primary health care in India because of its well established infrastructure and personnel in the field of maternal and child health care. As there is wide variation for infant mortality rate (IMR) in different states in India, so there is a need of deferential approach to implement community genetic services in states those had already achieved national goal of IMR. On the other hand, states those have not achieved the national goal on IMR priority should be given to management of other causes of infant mortality.

Reproductive failure in women living in iodine deficient areas of West Africa

OBJECTIVES

To investigate the association between iodine status and reproductive failure in a population of West African women.

DESIGN

Epidemiological survey on iodine deficiency disorders carried out in 1996-1997.

SETTING

The iodine deficient areas of Senegal (Casamance and Senegal Oriental).

POPULATION

Four thousand nine hundred and eighty women, aged 10 to 50, of whom 1,544 adolescent and 462 pregnant women were examined for thyroid size and urinary iodine excretion. Their iodine status was associated with their fertility rate and reproductive failures.

RESULTS

Reproductive failure (defined as repeated miscarriages and stillbirth) was associated with low iodine status, with severe iodine deficiency increasing the risk. Poor nutritional status and illiteracy had a significant effect on the outcome of pregnancy: underweight women had a fourfold higher risk, and those who were illiterate an eightfold higher risk, of failed pregnancy, compared with nutritionally healthy, literature women.

CONCLUSIONS

These findings emphasise the need to implement an effective iodine supplementation programme targeted at young and pregnant women in this area of western Africa. They also emphasise the importance of improving the nutritional status of young girls and the crucial role played by education in the prevention of reproductive failure.

Infant survival is improved by oral iodine supplementation

Although reports suggest that infant mortality is increased during iodine deficiency, the effect of iodine supplementation on infant mortality is unknown. A double-masked, randomized, placebo-controlled, clinical trial of oral iodized oil was conducted in Subang, West Java, Indonesia to evaluate the effect of iodine supplementation on infant mortality. Infants were allocated to receive placebo or oral iodized oil (100 mg) at about 6 wk of age and were followed to 6 mo of age. Six hundred seventeen infants were enrolled in the study. Infant survival was apparently improved, as indicated by a 72% reduction in the risk of death during the first 2 mo of follow-up (P < 0.05) and a delay in the mean time to death among infants who died in the iodized oil group compared with infants who died in the placebo group (48 days vs. 17.5 d, P = 0.06). Other infant characteristics associated with reduced risk of death included weight-for-age at base line, consumption of solid foods, female gender and recent history of maternal iodine supplementation. Oral iodized oil supplementation had a stronger effect on the mortality of males compared with females. This study suggests that oral iodized oil supplementation of infants may reduce infant mortality in populations at risk for iodine deficiency.