Neonatal Thyroid Function and Disorders

Synthroid, also known as levothyroxine, is a medication commonly prescribed to treat an underactive thyroid gland. However, when it comes to using Synthroid during pregnancy, there are both benefits and risks that need to be taken into account. Congenital hypothyroidism most often occurs when the thyroid gland does not develop properly, either because it is missing, is too small, or ends up in the wrong part of the neck. Also, sometimes the thyroid is missing the signal from the pituitary (master) gland, which tells it to produce thyroid hormone.

Thyroid Disease and Pregnancy

Although the incidence of persistent hypothyroidism does not appear to differ from term and preterm infants, the risk of transient hypothyroidism is higher in the latters (7). Aim of our work is to review the most significant reports regarding the relationship between prematurity/dysmaturity and the endocrine/metabolic future in the offspring. The thyroid hormone promotes fetal development by promoting protein synthesis, RNA, DNA, and specific enzymes 30,31. Before the 20th week of pregnancy, brain development primarily relies on the mother’s thyroid hormone. Because fetal thyroid follicular epithelial cells are immature and cannot make thyroid hormone initially, this hormone is delivered to the fetus by transplacental administration 32,33. Maternal thyroid hormone insufficiency in the latter stages of pregnancy may induce neurodevelopmental abnormalities, albeit the effects may be less severe than maternal thyroid shortage in the first trimester.

In a small number of cases, medications taken during pregnancy, mainly medications for treating an overactive thyroid, can lead to congenital hypothyroidism, which is temporary in most cases. This means if one child is affected, it is unlikely that other children you may have in the future will suffer from the same condition. Neonatal Graves’ disease occurs in about 1 percent of babies born to mothers with active Graves’ disease or a history of the disease. In less severe forms, and with good control, the consequences of Graves’ disease on the baby are usually temporary. However, even under the best of circumstances there may be permanent consequences of maternal Graves’ disease on the baby. The fetus of an iodine-deficient mother can be successfully treated if iodine supplementation is given during the first or second trimester.

Hyperthyroidism and pregnancy

It may be important in the first half of gestation, before the fetal thyroid gland is capable of T4 production, as well as the latter half of gestation when thyroid hormone effects on multiple organ systems are developing. Management of fetal thyroid dysfunction requires normalization of maternal serum T4 concentrations, avoidance or careful monitoring of synthroid depletion potentially goitrogenic drug effects in the fetus, and in some instances, direct or indirect fetal therapy. In most cases fetal hypothyroidism is sporadic and undetected, and prognosis for normal growth and development is excellent if the mother is euthyroid and the hypothyroid state is detected and adequately treated at birth.

For normal fetal development, an adequate quantity of thyroid hormone is necessary 17. By weeks of gestation, the fetal thyroid gland develops and produces the thyroid hormone. Until the fetus reaches 36 weeks of gestation, thyroid hormone levels in serum do not reach the levels of an adult 18.

It is always best to plan for pregnancy and to consult with your physician to ensure your thyroid status and treatment are optimized prior to becoming pregnant and monitored throughout your pregnancy. However, if this does not happen and you find out you are pregnant, you should contact your physician immediately to arrange for increased testing of your thyroid functions and a potential change in your medication. It seems clear that there is a great deal more to learn about the molecular mechanisms by which thyroid hormones support normal development of the brain. When considering the use of Synthroid during pregnancy, it’s essential to weigh the potential risks against the benefits.

Following an interprofessional approach when treating pregnant women with thyroid disease is vital.
Early studies found that children born to mothers with hypothyroidism during pregnancy had lower IQ and impaired psychomotor (mental and motor) development.
Exclusion criteria include hypothyroidism with comorbidities such as cardiovascular disease and other secondary pathologies.
There has been evidence of poor response in terms of attention, language, reading motor, and visual-spatial skills in infants born to hypothyroid mothers 38.

This has adverse effects on the fetus, including poor neurologic, cognitive, and musculoskeletal development. Pregnancy causes many changes to the thyroid gland and its function; thyroid hormone production during pregnancy increases by 50%. Thyroid autoantibodies can harm a pregnant individual and the fetus, as untreated hyperthyroidism and hypothyroidism in pregnancy pose risks to both mother and fetus. The course underscores the value of interprofessional collaboration, where the combined expertise of endocrinologists, obstetricians, nurses, and other healthcare professionals enhances patient outcomes.

Endocrine effects

The treatment for hyperthyroidism during pregnancy is indicated based on etiology as well as the severity of hyperthyroidism.
First, this is a longitudinal observational study instead of randomized clinical trial.
We compared the maternal characteristics between the treated and untreated group, however, did not find significant differences.
The etiology of this condition is heterogeneous; among the causes, there could be iodine excess or iodine deficiency.

When appropriately prescribed and monitored, taking Synthroid during pregnancy can provide several benefits for both the mother and the baby. The datasets generated and/or analyzed during the current study are not publicly available due to the Biosecurity Law of the P.R.C. but are available from the corresponding author on reasonable request. Each author declares that he or she has no commercial associations (e.g. consultancies, stock ownership, equity interest, patent/licensing arrangement etc.) that might pose a conflict of interest in connection with the submitted article.

Physiology of maternal thyroid in pregnancy

Treatment involves replacing the missing thyroid hormone to restore thyroid hormone levels to normal. The common form of thyroid hormone, considered the best treatment, is called levothyroxine (although it is synthetic, it is identical to theT4 produced by the body). Parents should crush up each day’s tablet, and then mix with a small volume (about 1 tsp) of liquid, either expressed breastmilk, water, or formula. This can be given to the baby on a teaspoon or by using a medicine dropper or syringe and squirting the suspension into the baby’s mouth (against the side or cheek pad). Levothyroxine should not be mixed with a soy protein formula, as soy protein binds thyroid hormone, reducing absorption from the gut. It is extremely important that parents administer thyroid hormone daily to maintain steady blood levels.

Pregnancy-Induced Alterations to Thyroid Function

The proportional of primipara and employment status were significant difference among Euthyroid, Untreated mild SCH and Treated mild SCH groups. The TSH level in both the Untreated and Treated mild SCH groups were significantly higher than Euthyroid group, the FT4 level in the Untreated and Treated mild SCH groups were significantly lower than Euthyroid group. There were no significant differences in TSH and FT4 levels between the Untreated and Treated mild SCH groups. Therefore, it is essential for pregnant women to prioritize their thyroid health and work closely with their healthcare providers to ensure that any thyroid disorders are properly managed throughout pregnancy.