An underactive thyroid (hypothyroidism) can wreak havoc on your fertility. In hypothyroidism, the thyroid—a butterfly-shaped gland in the neck—doesn’t produce enough hormones. This can interfere with ovulation, or the release of an egg. Your period may appear normal, so the only indication that something is wrong is that you can’t get pregnant. Hypothyroidism can also increase the risk of developing cysts on the ovaries, which can also decrease fertility. If you have symptoms of hypothyroidism—weight gain, feeling fatigued, difficulty dealing with cold temperatures—ask your healthcare provider about a thyroid test. Treating hypothyroidism with medications can often correct fertility problems.
If you have hypothyroidism and you do become pregnant, it’s important to work closely with your healthcare provider to make sure your thyroid levels are normal. Untreated or poorly controlled hypothyroidism has been linked to miscarriage and problems with fetal development.