Fertility & Thyroid

• TSH and Free T4: how well your thyroid is working.
• TPO and thyroglobulin antibodies: markers of thyroid autoimmunity.
• AMH: a hormone from small ovarian follicles, used to estimate egg supply.
• FSH and LH: the pituitary signals that drive the ovarian cycle.
• Estradiol: the main estrogen, read alongside FSH early in the cycle.
• Prolactin: a pituitary hormone. High levels can interfere with ovulation.

This panel suits women with a thyroid condition who are trying to conceive or planning to, and who want a baseline. It also suits women with irregular cycles or a family history of thyroid disease who want to check both areas early.

It does not check ovulation, which needs a timed progesterone test, or sperm health. If you have been trying for 12 months, or 6 months if you are 35 or older, talk with a fertility specialist.

Ideally, test before you start trying, so there is time to act on any thyroid result. If you take thyroid medication, your clinician will likely want to recheck TSH before conception and early in pregnancy.

Book your draw for cycle day 2 to 5, counting the first day of full flow as day 1, so FSH, LH and estradiol can be read correctly. AMH can be drawn on any day. If your cycles are irregular or absent, ask your clinician how to time the draw.

This panel requires fasting because of the prolactin test, so plan a morning draw on cycle day 2 to 5.

• Thyroid medication: if you take levothyroxine or another thyroid medication, have your blood drawn before that day's dose and bring the dose with you. Keep taking your medication as prescribed otherwise.
• Biotin: high-dose biotin, common in hair, skin and nail supplements, can distort many of these lab results. Stop it at least 2 to 3 days before your draw.
• Before the draw: avoid strenuous exercise and nipple stimulation, which can raise prolactin.
• Birth control: hormonal contraception can change FSH, LH and estradiol and can lower AMH. Tell your clinician if you use it.

Your report shows Quest's reference range next to each result.

• TSH: for women taking levothyroxine and planning pregnancy, American Thyroid Association guidance suggests a TSH below 2.5 mIU/L. Ask your clinician about your own goal.
• Thyroid antibodies: positive antibodies with normal thyroid function have been associated with a higher risk of miscarriage in studies. Your clinician can advise whether closer monitoring makes sense.
• AMH: lower levels suggest a smaller egg supply and higher levels are common with polycystic ovary syndrome. AMH does not predict your chance of conceiving naturally.
• FSH and estradiol: a high early-cycle FSH can suggest lower ovarian reserve, and a high estradiol can make a normal FSH look more reassuring than it is.
• Prolactin: mild elevations are common and can come from stress, some medications or an underactive thyroid, so a high result is usually repeated.