Thyroid Function Tests in Women with Infertility Attending a Clinic in Lagos State

Thyroid dysfunction is a frequently overlooked contributor to female infertility and pregnancy loss in Nigeria. This study examines thyroid function tests, specifically serum thyroid-stimulating hormone, free thyroxine, and free triiodothyronine, in women presenting with infertility at a reproductive health clinic in Lagos State, South West Nigeria. A cross-sectional study was conducted involving 200 women aged 20 to 45 years who had been trying to conceive for at least one year without success. A control group of 100 age-matched fertile women was also recruited. Blood samples were collected in the follicular phase of the menstrual cycle and analysed using enzyme-linked immunosorbent assay. Prolactin, follicle-stimulating hormone, and luteinising hormone levels were simultaneously determined to allow a comprehensive hormonal assessment. Clinical and reproductive histories were documented using structured questionnaires. The study aims to determine the prevalence of subclinical and overt thyroid dysfunction among infertile women in an urban Nigerian population and to evaluate its relationship with other reproductive hormone abnormalities. Findings will support the case for routine thyroid function screening in fertility workups across Nigeria. Keywords: thyroid function, infertility, TSH, female reproductive health, Lagos State.