It can take a while to get pregnant—depending on your age and medical history, anywhere from six months to one year is considered normal. But if you've been having a lot of unprotected sex with your partner at all the right times and still not seeing a plus sign on that pregnancy test, there may be a health issue inhibiting your ability to conceive.
Infertility has a number of causes. Here, Aaron K. Styer, M.D., reproductive endocrinologist and co-medical director of CCRM Boston breaks down the common reasons for female infertility. Men contribute to fertility problems, too; click here to read about what leads to male factor infertility. (If you have a known history of one of these issues, you might want to see a fertility specialist at the very beginning—when you’re just thinking about trying to conceive.)
“Regular ovulation—i.e. a cycle that lasts the same number of days every month and re-occurs at the same interval every month—is essential for women to conceive naturally,” Dr. Styer explains. The most common disorders impacting ovulation are polycystic ovary syndrome (PCOS), a hormone disorder that might result in irregular periods, too many androgens, and/or follicles surrounding your egg cells that prevent ovulation; hypogonadotropic hypogonadism, a hormone disorder most commonly seen in very lean women, athletes, and those with untreated eating disorders, which stops the brain from signaling the ovaries to begin selection of an egg; and ovarian insufficiency, severely reduced quality and number of eggs.
“Age-related infertility is one of the most common causes of female infertility,” notes Dr. Styer. “Women are born with millions of eggs, but the number of eggs decreases progressively from birth. At the same time, as women get older the quality of their eggs—or, the likelihood of an egg being genetically normal—decreases as well. As a result, the chance of conceiving is reduced and the risk of miscarriage is increased” as woman moves into her 30s and 40s. Fertility typically starts to decrease for most women around age 32, and then decreases even more rapidly after she turns 37. After age 35, a woman's eggs are even referred to as “geriatric.” How depressing.
Also known as a tubal blockage, tubal occlusion is when an ovulated egg is unable to be fertilized by sperm or to reach the endometrial cavity or uterus. And because normally the ovaries alternate which side releases an egg each month, if one is blocked, you might realistically only be able to conceive naturally every other month. If both fallopian tubes are blocked, then in vitro fertilization (IVF) is required. Some types of tubal blockage can affect implantation even after an embryo transfer via IVF and may require surgery, adds Dr. Styer.
Endometriosis is a disorder in which cells from the lining of the uterus grow in other locations in the abdomen and pelvis, and commonly, on the ovaries themselves. The inflammation that results from this disease may make the lining of the uterus less receptive to an embryo or cause scarring and blockage of the fallopian tubes, thus preventing fertilization from taking place.
Fibroids are common, benign tumors in the uterus, which are found in approximately 40 percent of women. Dr. Styer explains that while the presence of fibroids alone does not necessarily cause infertility or predispose a woman to pregnancy loss, fibroids that distort the uterine cavity can have an impact on the ability of an embryo to implant and should be removed surgically, often by laparoscopy.
Endometrial polyps are finger-like growths that come out of the lining of the uterus (a.k.a. the endometrium). Large polyps or multiple polyps can interfere with the ability of the embryo to implant and should be removed via surgery.
Even after a full fertility assessment, approximately one in five couples struggling to conceive will find that the exact cause of their infertility cannot be determined—but that doesn’t mean it’s all in your head.
“Unexplained infertility is not the same thing as having no explanation; rather, it reflects the fact that the tests performed have been normal,” emphasizes Dr. Styer. “There is always an explanation!”
In these cases, IVF will often reveal abnormalities in egg quality, sperm function, or embryo development that would not have been determined from standard treatment, Dr. Styer continues, adding that “thankfully, even when the cause of infertility is not known, various fertility treatments can eventually lead to the delivery of a healthy baby.”
Still have questions about getting pregnant? Check out our fertility FAQ here.
Editors’ note: We use the terms “woman” and “female” in this article to refer to people with internal reproductive organs; however we understand that not everyone with internal reproductive organs identifies as a woman or a female. We use the terms “man” and “male” to refer to people with external reproductive organs; however we understand that not everyone with external reproductive organs identifies as a man or a male.