How Vitamin D impacts ovarian reserve in fertility.

With many women delaying childbearing until their mid to late thirties, the testing and treatment for ovarian reserve has taken centre stage in the field of fertility medicine. Testing for ovarian reserve includes looking at hormone levels (often on Day 3 of a woman’s cycle) and a particular test called Anti-Mullerian Hormone or AMH.

AMH is produced from follicles in the ovary, and can be measured in the blood at any point in the menstrual cycle, or even if women are on an IUD or oral contraceptive. It measures ovarian reserve, which is a prediction of how many eggs remain to be released in a woman’s reproductive lifetime.

AMH is impacted by various lifestyle factors such as smoking and alcohol, medication such as chemotherapy or can be lowered from ovary damage including during surgery for endometriosis. AMH also declines steadily with age, which can help women who are over 30 make decisions about their future fertility care.

An interesting correlation has been made between vitamin D deficiency and AMH levels. Vitamin D is commonly deficient in women who live in North America and appears to be even lower in women who suffer with PCOS, endometriosis and early ovarian failure. Vitamin D is also lower in women who smoke, who don’t have a regular exercise routine, or who are above their ideal body weight.

Vitamin D is vital for fertility because it helps support the connection between the embryo and the mother’s uterine lining. It helps support maternal-fetal connection and helps support implantation. Low levels of Vitamin D have been strongly linked to miscarriage.

Studies have looked specifically at the impact of Vitamin D on AMH levels, and have shown two interesting findings:

• When Vitamin D is low, AMH also tends to be low. This may be related to how many Vitamin D lowering health behaviors also impact fertility such as diet and lifestyle¹.

• When we treat women with Vitamin D deficiency, her AMH levels may improve²

Both Vitamin D and AMH should be tested routinely in women over 30 who have future goals of getting pregnant. These simple tests can help women understand her fertility and help us create a treatment plan that focus on her goals and needs as she pursues her fertility journey.

1.         Ersoy, E. et al. Vitamin D Levels in Patients with Premature Ovarian Failure. Ginekol. Pol. 87, 32–36 (2016).

2.         Grzechocinska, B., Dabrowski, F. A., Cyganek, A. & Wielgos, M. The role of vitamin D in impaired fertility treatment. Neuro Endocrinol. Lett. 34, 756–762 (2013).