Making a baby is a complex process that's contingent upon four crucial steps:
- A woman and man each producing eggs and sperm
- Healthy fallopian tubes that allow the sperm to easily get to the egg
- Sperm's ability to fertilize the egg upon reaching it
- A fertilized egg's ability to attach to the uterus and continue developing normally
Infertility may result when there's a hiccup in one or more of these steps. Because conception is so complicated, there are a number of factors that can lead to infertility in women:
Fallopian tube damage is the primary cause of infertility in women, occurring in about 30 percent of cases. If your fallopian tubes are scarred or blocked, sperm may have difficulty reaching your egg, or your fertilized egg may not be able to safely travel to your uterus to develop into a healthy baby. Having very painful periods or a history of pelvic pain are common signs of fallopian tube damage.
Fallopian tubes may become blocked or damaged in a few ways. Often, it's from an infection called pelvic inflammatory disease, which usually results when sexually transmitted diseases like chlamydia and gonorrhea go untreated (they're easily curable with antibiotics).
Another cause is endometriosis, a condition where the tissue that normally lines the uterus starts growing where it shouldn't -- like in the fallopian tubes, ovaries, or other nearby organs. If this tissue blocks openings in the ovaries or fallopian tubes, it can prevent an egg from being released or fertilized.
In rarer cases, fallopian tube damage may be due to having a prior ectopic pregnancy (where the fertilized egg implants outside of the uterus). Ectopic pregnancies are very dangerous for moms-to-be; because they need to be terminated as soon as possible, they don't result in live births.
Ovulation problems occur about 20 percent of the time. If you don't ovulate normally, then you're not releasing healthy eggs for sperm to fertilize. The main symptoms of ovulation roadblocks are irregular or missing periods.
Ovulation problems usually result from hormonal imbalances. The female sex hormones LH, FSH, and estrogen are the big ones needed to launch an egg each menstrual cycle -- if they're released at the wrong time or in the wrong amounts, it can throw off ovulation. Weighing too much or too little can also mess with your hormones and hinder ovulation.
Up to 10 percent of all women experience a condition called polycystic ovarian syndrome (PCOS), where a hormone imbalance triggers the body to produce excess testosterone, which can also hinder ovulation. Women with PCOS may be overweight and have excess body or facial hair and acne, in addition to irregular or missing periods.
Problems with the uterus occur about 20 percent of the time. If your egg can't attach normally to the wall of the uterus, it can't continue developing into a healthy fetus. Unexplained lower-abdominal pain or bloating may be a sign of uterine problems that can affect fertility. This may be due to fibroids or polyps, which are benign tissue growths from the wall of the uterus; they may sometimes affect fertility depending on their size and location. Scar tissue in the uterus from infection, miscarriage, or abortion may also play a role.
The remaining causes of infertility in women may include immune system diseases, kidney disease and diabetes, early menopause, cancer and treatment for it (like chemotherapy and radiation), or taking certain medications (some drugs that treat blood pressure, depression, or asthma, for example, may impact fertility).