Preexisting Thyroid Disease in Pregnancy: A Brief Overview
We sincerely thank the research group of the Peking University Retrospective Birth Cohort in Tongzhou based on the hospital information system. We appreciate the health professionals in the Tongzhou Maternal and Child Health Care Hospital of Beijing for data collection and management. The most common manifestation in sheep, cattle, pigs and horses is a high incidence of stillbirths and birth of small, weak offspring. By taking proactive steps to maintain thyroid health during pregnancy, women can help ensure the best possible outcomes for both themselves and their babies.
Thyroid Disease and Pregnancy
It controls how quickly the body uses energy, affects weight, and influences the functioning of various organs and systems. When the thyroid gland fails to produce enough thyroxine, the body’s metabolism slows down, leading to symptoms such as fatigue, weight gain, and depression. The hormone in the pill is identical to what is made in the body, and you are just replacing what is missing. In general, side effects occur only if the dose is too high, which the endocrinologist can avoid by checking blood levels on a periodic basis.
A Narrative Review on the Effect of Maternal Hypothyroidism on Fetal Development
Remember, transient subclinical hyperthyroidism can be seen during the first trimester of pregnancy due to adaption in thyroid physiology, as discussed above. Additionally, in Graves disease, TSH receptor antibodies are elevated on blood testing. There is an increase in iodine requirement during pregnancy due to increased maternal thyroid hormone production, as well as an increase in renal iodine clearance. However, in areas of iodine deficiency, where iodine requirements are not optimally replenished, maternal iodine deficiency frequently results.
Availability of data and materials
- Subclinical hyperthyroidism, as well as gestational thyrotoxicosis, do not require treatment during pregnancy, and rather, observation is recommended with periodic monitoring of thyroid function tests every 4 to 6 weeks.
- The primary care provider or the pediatric endocrine specialist will give instructions for how often the blood tests are monitored.
- There is an increase in iodine requirement during pregnancy due to increased maternal thyroid hormone production, as well as an increase in renal iodine clearance.
- Before a baby is born and up to 2 to 3 years of life, thyroid hormone is very important for brain development.
This may involve regular monitoring of thyroid hormone levels, medication adjustments, and close monitoring of the baby’s growth and development. During pregnancy, the body’s demand for thyroid hormones increases to support the growth and development of the baby. However, the production of hCG can also interfere with the normal functioning of the thyroid gland, leading to imbalances in thyroid hormone levels. Overt hyperthyroidism during pregnancy is characterized by decreased TSH and increased free T4 levels. Subclinical hyperthyroidism is characterized by decreasedTSH and normal free T4 levels.
What are the signs and symptoms of congenital hypothyroidism?
Treatment for subclinical hypothyroidism is generally recognized to be beneficial in preventing adverse events, particularly pregnancy loss. Most study results show greater improvement when thyroid replacement is initiated earlier in pregnancy. Before a baby is born and up to 2 to 3 years of life, thyroid hormone is very important for brain development. After this time, thyroid hormone is important for growth as well as enabling the body to use energy and stay warm (metabolism) and to help the brain, heart, muscles, and other organs work as they should. Congenital hypothyroidism occurs when a newborn infant is born without the ability to make normal amounts of thyroid hormone. The condition occurs in about 1 in 3,000-4,000 children, is most often permanent and treatment is lifelong.
- When there is a positive result (a low level of thyroid hormone with a high level of thyroid-stimulating hormone, called TSH, from the pituitary), the screening program immediately notifies the baby’s doctor, usually before the baby is 2 weeks old.
- In the recent ATA guideline in 2017, LT4 treatment is considered for mild SCH pregnant women with TPOAb positive, but LT4 treatment is not recommended for mild SCH pregnant women with TPOAb− 11.
- This setting provided us the opportunity to compare the LT4 treated and untreated groups to evaluate the adverse effect of LT4 treatment among those women.
The developing fetus is initially reliant upon maternal thyroid hormones that cross the placenta, until the fetal thyroid begins to supply thyroid synthroid reliability hormone for the fetus. Maternal thyroid status affects fetal thyroid function and maternal thyroid dysfunction can have a significant impact on the fetus and neonate. Here, we describe thyroid function in the fetus and neonate and discuss the most common thyroid disorders seen in neonates.
Levothyroxine is excreted into breast milk, but levels are too low to alter thyroid function in the infant or to interfere with neonatal thyroid screening programs. Periodic monitoring with an annual serum TSH concentration for the mothers is generally recommended. For patients with chronic lymphocytic thyroiditis (CLT), also called Hashimoto’s thyroiditis, there is some evidence to suggest an increased risk of pregnancy loss.
In the management and screening of thyroid disease in pregnancy, there are few areas where the ATA recommendations differ from what ACOG suggests in clinical guidelines. For example, the ATA suggests mothers with thyroid disease have labs checked every four weeks, while ACOG recommends every four to six weeks. Thyroid hormones are critical for development of the fetal and neonatal brain, as well as for many other aspects of pregnancy and fetal growth. Hypothyroidism in either the mother or fetus frequently results in fetal disease; in humans, this includes a high incidence of mental retardation. It is important to note that Synthroid is not only used during pregnancy but also in individuals who have hypothyroidism outside of pregnancy.
Ethical considerations must guide decision-making, ensuring informed consent and respecting patient autonomy in treatment choices. Each healthcare professional must know their responsibilities and contribute their unique expertise to the patient’s care plan, fostering a multidisciplinary approach. Effective interprofessional communication is paramount, allowing seamless information exchange and collaborative decision-making among the team members. Care coordination plays a pivotal role in ensuring that the patient’s journey from diagnosis to treatment and follow-up is well-managed, minimizing errors and enhancing patient safety.
The usual range of TSH during pregnancy is now re-established to 2.5 mlU/L during the first three months of pregnancy and 3.0 mlU/L during the remaining six months 7,8. Sufficient levels of this hormone are necessary for average growth and development 9,10. Brain development depends on the maternal iodine supply, which transports T4 into the fetus, thus proving the importance of the proper amount of iodine in the diet 4,5. Hence, optimal levels of thyroid hormones are necessary for the proliferation and differentiation of cytotrophoblasts. The most common cause of gestational hypothyroidism is a deficiency in iodine levels 11.
