fertility
Common Causes of Female Infertility Explained
The most common causes of female infertility are ovulation disorders (including PCOS), blocked or damaged fallopian tubes, diminished ovarian reserve, and uterine structural problems. In about a third of cases, infertility involves factors in both partners, so a full workup includes semen analysis.
When does difficulty conceiving warrant an evaluation?
The standard recommendation is to seek evaluation after 12 months of regular, unprotected intercourse if you are under 35, and after 6 months if you are 35 or older — because age-related fertility decline accelerates and earlier evaluation preserves more options 1Ref 1Practice Committee of the American Society for Reproductive Medicine (2021).Fertility evaluation of infertile women: a committee opinion.Comprehensive framework for evaluating female infertility including timing of referral, tests for ovarian reserve, tubal patency, and uterine assessment. Some situations call for earlier evaluation regardless of age:
- Irregular or absent periods (suggesting possible ovulation problems)
- Known history of pelvic inflammatory disease (PID), sexually transmitted infection, or prior pelvic surgery
- Endometriosis diagnosis
- Two or more miscarriages
- Any known reproductive structural abnormality
A reproductive endocrinologist or gynecologist will typically begin with bloodwork, a pelvic ultrasound, a uterine assessment, and a semen analysis of any male partner.
Ovulation disorders
Ovulation problems are among the most common identifiable causes. They include:
Polycystic ovary syndrome (PCOS) is one of the most frequent causes of anovulatory infertility 2Ref 2American College of Obstetricians and Gynecologists (2018).ACOG Practice Bulletin No. 194: Polycystic Ovary Syndrome.PCOS as one of the most common causes of anovulatory infertility, and ovulation induction as primary treatment. PCOS involves elevated androgens and typically irregular periods. Many people with PCOS ovulate unpredictably rather than not at all. It is also associated with insulin resistance, which can compound the hormonal disruption. Ovulation induction with letrozole or clomiphene is often an effective first step.
Hypothalamic amenorrhea — the brain's reproductive signaling shuts down in response to very low body weight, intense exercise, or significant emotional stress. Periods stop, and ovulation does not occur until the underlying cause is addressed.
Elevated prolactin (hyperprolactinemia) — prolactin is normally elevated during breastfeeding and suppresses ovulation. In non-breastfeeding individuals, a pituitary adenoma or certain medications can cause prolactin to rise and disrupt ovulation.
Primary ovarian insufficiency (POI) — ovarian function declines before age 40, causing irregular or absent periods and very low estrogen. This is distinct from normal age-related decline.
Fallopian tube problems
The fallopian tubes must be open for an egg to travel from the ovary toward the uterus and for sperm to reach the egg. Causes of tubal blockage or damage include:
- Prior pelvic inflammatory disease (PID) — often caused by untreated chlamydia or gonorrhea, which can scar the tube interior
- Prior ectopic pregnancy — treated ectopic pregnancies may leave scar tissue, and the affected tube may have reduced function or be surgically removed
- Endometriosis — can involve the tubes directly or create adhesions (scar tissue bands) that distort their position
- Prior pelvic surgery — appendectomy, ovarian cyst removal, or other procedures can leave adhesions affecting tubal function
Tubal patency is typically assessed with a hysterosalpingogram (HSG) — an X-ray dye study — or a saline infusion sonogram. If tubes are blocked or significantly damaged, IVF (which bypasses the tubes) is usually recommended 1Ref 1Practice Committee of the American Society for Reproductive Medicine (2021).Fertility evaluation of infertile women: a committee opinion.Comprehensive framework for evaluating female infertility including timing of referral, tests for ovarian reserve, tubal patency, and uterine assessment.
Diminished ovarian reserve
Ovarian reserve refers to the remaining quantity and quality of eggs. It is assessed through:
- Anti-Müllerian hormone (AMH) blood test — reflects the pool of remaining follicles
- Antral follicle count (AFC) — follicles visible on ultrasound at the start of a cycle
- Day 3 FSH and estradiol — elevated FSH indicates the pituitary is working harder to stimulate a declining ovarian pool
Diminished ovarian reserve can occur earlier than expected in some people due to genetics, prior ovarian surgery, smoking, or autoimmune conditions. It does not necessarily mean conception is impossible, but it does affect the response to ovarian stimulation and typically warrants expedited evaluation and treatment.
Uterine and structural factors
Even when ovulation and tube function are normal, the uterine cavity must be able to support implantation. Factors that can interfere include:
- Uterine fibroids (leiomyomas) — benign tumors; submucosal fibroids (those bulging into the uterine cavity) are most likely to affect implantation 3Ref 3American College of Obstetricians and Gynecologists (2021).Management of Symptomatic Uterine Leiomyomas: ACOG Practice Bulletin, Number 228.Submucosal fibroids as most likely fibroid type to impair implantation and fertility
- Endometrial polyps — small outgrowths of the uterine lining that may obstruct the cavity
- Uterine septum or other congenital shapes — an abnormal uterine shape present since birth
- Asherman's syndrome — intrauterine scar tissue from prior surgery (such as dilation and curettage) or infection
Endometriosis deserves special mention because it affects multiple parts of the reproductive system. Tissue similar to the uterine lining grows outside the uterus — on the ovaries, tubes, bowel, or pelvis — causing inflammation, adhesions, and sometimes ovarian cysts (endometriomas) 4Ref 4Practice Committee of the American Society for Reproductive Medicine (2012).Endometriosis and infertility: a committee opinion.Endometriosis as a cause of infertility via multiple mechanisms including inflammation, adhesions, and ovarian involvement. Even minimal endometriosis can reduce fertility through mechanisms that are not fully understood.
Unexplained infertility
After a complete evaluation, roughly 10–30% of couples have no identifiable cause found. This is termed unexplained infertility. It is frustrating to hear, but it does not mean nothing is wrong — it means current testing has not identified the specific problem. Many couples with unexplained infertility conceive with empiric treatment such as IUI with ovarian stimulation or IVF 5Ref 5Practice Committee of the American Society for Reproductive Medicine (2020).Evidence-based treatments for couples with unexplained infertility: a guideline.IUI with ovarian stimulation and IVF as evidence-based options for unexplained infertility.
Common questions
Can stress cause infertility?
Extreme physical stress — such as very low body weight or overtraining — can suppress the brain's reproductive signaling and stop ovulation. Everyday emotional stress is unlikely to be a primary cause of infertility on its own, though it is a real part of the experience. If your periods are regular and ovulation is confirmed, stress alone is not the likely explanation.
Does having PCOS mean I cannot get pregnant?
No. PCOS is one of the most common and also one of the most treatable causes of ovulatory infertility. Many people with PCOS conceive with ovulation-inducing medications (letrozole is now commonly preferred) and a supportive clinical team.
Do I need to see a specialist, or can my OB-GYN help?
For many straightforward situations — a healthy 29-year-old with irregular cycles — a gynecologist can start the initial evaluation and even begin treatment. A reproductive endocrinologist (a subspecialty of OB-GYN with additional fertility training) is recommended if you are 35 or older, have a known reproductive condition, have had prior infertility treatment, or if the initial workup reveals a complex issue.
Is infertility more often a female or male issue?
Neither — roughly one-third of infertility is attributable to female factors, one-third to male factors, and one-third involves both partners or is unexplained. This is why a semen analysis is a standard part of any fertility evaluation.
When to seek evaluation sooner
- —Absent or very irregular periods — this suggests possible ovulation problems that warrant evaluation without waiting 12 months
- —Pelvic pain, especially during periods or intercourse — possible sign of endometriosis or other pelvic pathology
- —Prior diagnosis of an STI (especially chlamydia or gonorrhea) without confirmed treatment — risk of tubal damage
This article is for general health education and does not replace a clinical evaluation. Infertility has many possible causes and requires individualized assessment by a clinician — typically a gynecologist or reproductive endocrinologist. Gale can help you prepare questions and find a specialist.
References
- 1.Practice Committee of the American Society for Reproductive Medicine (2021). Fertility evaluation of infertile women: a committee opinion. Fertility and Sterility. doi:10.1016/j.fertnstert.2021.08.038 ✓Comprehensive framework for evaluating female infertility including timing of referral, tests for ovarian reserve, tubal patency, and uterine assessment
- 2.American College of Obstetricians and Gynecologists (2018). ACOG Practice Bulletin No. 194: Polycystic Ovary Syndrome. Obstetrics & Gynecology. doi:10.1097/AOG.0000000000002656 ✓PCOS as one of the most common causes of anovulatory infertility, and ovulation induction as primary treatment
- 3.American College of Obstetricians and Gynecologists (2021). Management of Symptomatic Uterine Leiomyomas: ACOG Practice Bulletin, Number 228. Obstetrics & Gynecology. doi:10.1097/AOG.0000000000004401 ✓Submucosal fibroids as most likely fibroid type to impair implantation and fertility
- 4.Practice Committee of the American Society for Reproductive Medicine (2012). Endometriosis and infertility: a committee opinion. Fertility and Sterility. doi:10.1016/j.fertnstert.2012.05.031 ✓Endometriosis as a cause of infertility via multiple mechanisms including inflammation, adhesions, and ovarian involvement
- 5.Practice Committee of the American Society for Reproductive Medicine (2020). Evidence-based treatments for couples with unexplained infertility: a guideline. Fertility and Sterility. doi:10.1016/j.fertnstert.2019.10.014 ✓IUI with ovarian stimulation and IVF as evidence-based options for unexplained infertility
5 sources, numbered by first appearance. General health information, not medical advice — synthetic demonstration content.