Planning a Baby? Don’t Ignore Even ‘Borderline’ Thyroid Levels- Doctor Explains

Even minor thyroid issues might delay pregnancy. The thyroid, the body's biggest gland, controls metabolism and hormonal balance, which are crucial for ovulation, implantation, and early pregnancy. 

Thyroid disorders can delay pregnancy even when symptoms are mild or barely noticeable. Thyroid is the largest gland in the body and its main function is to control metabolism and hormonal balance which includes hormonal activities very important for an ovary, implantation and very early pregnancy. Even slight changes in thyroid function can upset the balance of these processes which will result in a pregnant woman who is regular with her periods and is not suffering from any illness unable to conceive.

How the thyroid affects fertility

Thyroid hormones and reproductive hormones such as estrogen, progesterone, luteinizing hormone and follicle-stimulating hormone are said to have a very close interaction. A slight impairment in thyroid function will lead to disruption in this coordination. In the case of mild or subclinical hypothyroidism the situation is that TSH levels are high while thyroid hormone levels are normal. Not all women experience the symptoms clearly but ovulation may not be regular or of lesser quality. Moreover, the quality of the egg can also be reduced and the resulting increase in prolactin may further inhibit ovulation. Thus, the chances of pregnancy being delayed are there even when the menstrual cycle appears regular. 

Even mild hyperthyroidism can indirectly affect human fertility. The main effect of excess thyroid hormone is that it alters the estrogen metabolism and, at the same time, increases sex hormone–binding globulin thereby changing the amount of active estrogen available to the body. This situation may cause irregular ovulation, shortened luteal phases and reduced chances of implanting the embryo. Patients complaining of anxiety, palpitations, or weight changes are sometimes thought to be under stress; thus, the condition goes undiagnosed and the patient's fertility remains affected.

Autoimmune thyroid disease matters even with normal hormones 

The situation becomes even more complicated with autoimmune thyroid disease. Autoimmunity-related disorders like Hashimoto’s thyroiditis or Graves’ disease can affect fertility even if thyroid hormone levels are within the normal range. The presence of thyroid antibodies has been associated with lower ovarian reserve, poor implantation, and a higher risk of early miscarriage. Chronic, low-grade inflammation caused by autoimmune activity might disrupt the development of uterine lining and embryo, the factor contributing to the burden of delays in achieving pregnancy repeatedly.

Thyroid hormones are of utmost necessity even after conception. Their support to the endometrial receptivity and the early placental development is indispensable. Mild thyroid dysfunction not only increases the chances of implantation failure, biochemical pregnancies and early pregnancy loss but also risks these confusions. Many of such losses are misidentified as undone pregnancies since they occur before a pregnancy is clinically confirmed. Thus, women who are going through the recurrent losses might not even realize that the thyroid health is their hidden ally behind the constant setbacks.

Thyroid-related fertility issues often go unnoticed for one reason that symptoms lack specificity. The symptoms of fatigue, hair loss, a little weight gain, mood swings and inability to tolerate cold are usually associated with stress from lifestyle, anemia or getting old. Thus, women might be diagnosed with unexplained infertility while the underlying thyroid imbalance is not treated.

Finding the thyroid problems is not complicated and is not expensive either. The blood tests that check TSH, free T4 and thyroid antibodies can even spot the slightest of abnormalities. A TSH level below 2.5 mIU/L is what most experts suggest for women who are about to conceive. Quick medical intervention, which is usually with a low-dose drug, can bring back the normal ovarian function, increase the chance of implantation, lower the risk of abortion, and, furthermore, remarkably reduce the time taken for a couple to get pregnant. 

Conclusion 

Thyroid diseases may still cause infertility or prolonged conception time in women who show little or no signs of the disease. Subclinical hypothyroidism, mild hyperthyroidism and autoimmune thyroid disease are likely to have an impact on ovulation, implantation and early pregnancy without the woman being aware of it. Pregnancy delays and reduced fertility may be the result of very simple and effective measures such as early screening and prompt therapy.

Dr. Shwetha S Kamath, Consultant - Obstetrics & Gynecology, Advanced Laparoscopy, Infertility & High-risk pregnancy, Rainbow Children’s Hospital, Hebbal