Thyroid problems are common and, importantly for anyone trying to conceive, they can interfere with fertility, pregnancy health, and assisted reproduction outcomes. In India, where both iodine nutrition and autoimmune thyroid disease patterns vary regionally, thyroid dysfunction shows up frequently in women of reproductive age and in infertility clinics.
This article explains how thyroid disorders affect fertility, summarizes Indian data and guidance, and offers practical steps for screening and management for couples planning pregnancy.
The thyroid gland produces hormones (mainly T4 and T3) that regulate metabolism and interact closely with the reproductive endocrine system. Abnormal thyroid function can disrupt menstrual cycles and ovulation, alter sex-hormone levels, and increase the risk of miscarriage and other adverse pregnancy outcomes. Both overt hypothyroidism (clearly low thyroid hormone) and subtler abnormalities (like subclinical hypothyroidism or thyroid autoimmunity) can matter — sometimes before a pregnancy is even established.
Recent Indian analyses show a high burden of thyroid dysfunction among infertile women. A 2024 pooled analysis found that roughly 28% of women presenting with infertility had hypothyroidism (overt or subclinical), although prevalence varied by region and study methods. Many cases are previously undiagnosed at presentation. This elevated prevalence is explained by a mix of iodine nutrition differences, autoimmune thyroiditis, and limited screening in some settings.
Key ways thyroid dysfunction interferes with conception include:
Subclinical hypothyroidism has elevated TSH with normal free T4, is frequent and controversial. Several observational studies and meta-analyses associate SCH in the preconception period with higher miscarriage risk and, in some reports, worse assisted-reproduction (IVF/IUI) outcomes. However, randomized data are limited, and professional bodies differ on whom to treat and when. The American Society for Reproductive Medicine and other groups have reviewed the evidence and highlighted benefits in certain high-risk groups while acknowledging unresolved questions.
Indian expert groups recommend proactive attention to thyroid status in women planning pregnancy:
Treatment with levothyroxine (thyroid hormone replacement) for overt hypothyroidism is standard and clearly improves pregnancy outcomes. For SCH, several studies suggest that treating elevated TSH prior to ART or conception may improve oocyte quality, fertilization rates, and reduce miscarriage in some cohorts — though the magnitude of benefit and which TSH cutoff to use can differ between guidelines and patient situations. Clinicians generally individualize decisions based on TSH value, presence of thyroid antibodies, infertility history, and planned interventions.
Several studies indicate that untreated hypothyroidism or an elevated preconception TSH may be associated with poorer IVF outcomes (maturation, fertilization, implantation) and higher early pregnancy loss; conversely, early detection and correction of thyroid dysfunction before ART have been linked with improved results in some cohorts. Because IVF clinics can identify subclinical problems, infertility care pathways commonly include thyroid screening as standard practice.
In India, region-to-region variations in iodine intake, accessibility of endocrine care, and awareness contribute to underdiagnosis. Studies report that a substantial proportion of women with infertility have previously unrecognized hypothyroidism. Strengthening routine preconception screening, making thyroid tests widely available, and educating women and primary-care providers about the reproductive consequences of thyroid disease would help bridge the gap.
Thyroid disorders are a common and treatable cause of reduced fertility and adverse pregnancy outcomes. For women trying to conceive, particularly those with irregular cycles, a history of miscarriage, autoimmune disease, or those undergoing ART, checking thyroid function is a sensible, evidence-based step. Overt hypothyroidism requires treatment; management of subclinical cases should be individualized, often in consultation with an endocrinologist or fertility specialist. With timely diagnosis and appropriate therapy, most women with thyroid disease go on to have successful pregnancies.