There are many causes of infertility. I am not an obstetrician nor a gynecologist. I get many referrals to help women of all ages get pregnant. The overall health needs of both partners need to tested, This includes testing for heavy metals, food allergies and autoimmune testing
I feel a change in dietary lifestyle is needed. I do recommend a dietary lifestyle low in carbohydrates and foods low in acidity . There should be low dairy and low glycemic fruits and vegetables. There could problems with female structures, failure of eggs to mature properly, endometriosis could be present and much more. On the male side there could be systemic disease present that need to be checked. For both men and women I need to balance the thyroid, the vitamin D levels and maintain a good balance of B12, B6 and folic acid. This might involve testing both male and female for any methylation gene.
I also discuss stress with both the woman and the man. Stress increases glucocorticosteroids which reduce testosterone in tests in men. In females the stress inhibits gonadotrophin releasing hormone in females.
A couple trying to have children need to sit with an Integrative Physician, or a Naturopathic Doctor to get the full spectrum of causes of infertility.