In the United States, when the female partner has regular, monthly cycles, approximately 15% of couples do not conceive after a year of unprotected intercourse. This is why it is advised to see a fertility specialist if a woman under 35 has not conceived after one year.
Due to the fact that couples in the general population (who do not have difficulty conceiving) have a per month pregnancy rate of 20-25% until age 35-37, a woman over the age of 35 is advised to see a fertility specialist if she is not pregnant after 6 months of trying to conceive.
Women who do not have a monthly cycle (for example, those with polycystic ovary syndrome), or couples in which another identifiable barrier to conception has been diagnosed (for example, advanced endometriosis, abnormal ovarian reserve testing, blocked fallopian tubes, significant male factor), are advised to seek help from a fertility specialist.
Causes of Infertility:
Polycystic Ovary Syndrome (PCOS) – approximately 10% of reproductive age women do not ovulate every month because of PCOS. Women with PCOS have two of the following: 1) infrequent or absent ovulation, 2) excessive hair growth on lips, chin, face, chest, or middle of abdomen, 3) Polycystic-appearing ovaries at transvaginal ultrasound (many small cyst-like “follicles”, each containing an oocyte/egg. In addition, conditions such as hypothyroidism, increased prolactin levels, and less common conditions called congenital adrenal hyperplasia and Cushing’s syndrome should be ruled out.
Diminished egg reserve – egg number and egg quality declines over time.
Hypothyroidism – low thyroid hormone (high TSH) can affect ovulation and decrease the chances of conception and increase the risk of miscarriage.
Hyperprolactinemia – increased prolactin levels can also affect ovulation.
Hypothalamic amenorrhea – women can have a lack of ovulation due to extreme weight loss, extreme exercise, or eating disorders such as anorexia/bulemia.
Blockage – fallopian tubes can be blocked due to previous infection, surgery, endometriosis, or even a ruptured appendix.
Endometrial polyps – these are growths in the uterine cavity and the cells are made of the lining of the uterus. Polyps are almost always benign, especially in women of reproductive age.
Uterine fibroids – these are growths in the muscle of the uterus that can sometimes grow into the uterine cavity and make it more difficult to conceive and can increase the risk of miscarriage.
Intrauterine scar/adhesions – these are bands of tissue that can result from a previous surgery or infection. Intrauterine adhesions can occupy the space where implantation of an embryo potentially occurs, decreasing pregnancy rates and increasing miscarriage rates.
Uterine anomalies – different shaped uterus may affect pregnancy rates and miscarriage rates, depending on the specific shape.
Approximately 6-10% of reproductive age women and 30% of infertility patients have endometriosis, which is a condition where cells that make the lining of the uterus can grow outside the uterus and be associated with difficulty conceiving.
Also known as “scar tissue”, adhesions are bands of tissue that can cause the uterus, fallopian tubes, ovaries, and intestines to attach to each other and can be associated with difficulty conceiving. Scar tissue can result from a previous surgery or infection, and also can be a feature of endometriosis.
There are many reasons why semen analysis parameters may be low – if a reason is found, it may be due to hormones, anatomy, genetics, or environmental.
If all of the tests to evaluate fertility are normal and a cause for difficulty conceiving is not found, then the couple may have unexplained subfertility.
"Discussing Infertility" - 06/10/10