Secondary infertility is the medical term for having fertility troubles after having at least one child without difficulty. With the exception of congenital birth defects or genetic problems, the causes for secondary infertility are the same as those for primary infertility. Female fertility troubles arise from problems with the ovaries, the fallopian tubes or the uterus. Male fertility troubles arise from problems with the testicles including low male hormone production and low or absent sperm production.
Fertilization Failure
Fertility trouble can arise from pelvic inflammatory disease (PID), which results from sexually transmitted diseases that can scar shut the fallopian tubes, the natural site of fertilization, making fertilization impossible. Previous abdominal surgeries can cause scarring and adhesions on ovaries and fallopian tubes causing them to adhere together, preventing fertilization by inhibiting egg release and pick-up of the egg by the Fallopian tube, states the American Pregnancy Association.
Fertilization also requires healthy normal sperm capable of fertilizing an egg. In the male, sexually transmitted diseases, if left untreated, can damage the testis or epididymis (the sperm storage organ). Infections in these organs can create blockages preventing the production and the release of sperm during intercourse, preventing fertilization. Physical trauma to the testicles can also damage these sites of sperm and male hormone production resulting in secondary infertility, according to the National Library of Medicine.
Ovarian Problems
The ovaries produce female hormones, estrogen and progesterone, and also drive the production of mature eggs in response to hormonal signals produced by the pituitary and hypothalamus glands in the brain. Cancer occurring either in the brain or in the ovaries can disrupt the signaling process to the ovaries and ovarian function. Cancer can cause secondary infertility by either directly damaging the ovaries or through side effects of chemotherapy and radiation treatments used to fight the cancer.
Morbid obesity can cause hormonal imbalances that disrupt the normal functioning of the ovaries, causing irregular or absent periods. Severe malnutrition causing anorexia can also cause periods to cease, causing secondary infertility.
The normal processes of aging decrease fertility, particularly in women. After the age of 35, fertility begins to decline rapidly so that most women in their early forties have less than 10 percent chance of pregnancy each month, according to the American Society for Reproductive Medicine.
Implantation Problems
Endometriosis is a disease in which the cells lining the uterus begin to grow in areas outside the uterus, such as the fallopian tubes, which can can cause problems with embryo implantation. Endometriosis tissue growing in the fallopian tubes produces toxic fluid which causes the fallopian tubes to balloon, creating an abnormal swelling called a hydrosalpinx. Leakage of toxic fluid from these swollen tubes into the uterus can create an inhospitable environment for the implanting embryo, according to U.S. News Health.
Fibroids are a kind of benign uterine growth that develop over time and can become large, taking up space inside the uterus, interfering with implantation and later stages of pregnancy.
