Most couples achieve pregnancy within the first six months of trying. Overall, after 12 months of frequent unprotected intercourse, about 90 percent of couples will become pregnant. The majority of couples will eventually conceive, with or without treatment.
The main sign of infertility is the inability for a couple to get pregnant. There may be no other obvious symptoms.
In some cases, an infertile woman may have irregular or absent menstrual periods. An infertile man may have signs of hormonal problems, such as changes in hair growth, sexual function, reduced sexual desire, or problems with ejaculation. He may also have small testicles or a swelling in the scrotum.
When to see a doctor
In general, you may consider seeing a doctor about infertility if you and your partner have been trying regularly to conceive for at least one year. You may consider being seen earlier if you're a woman and:
- You're age 35 to 40 and have been trying to conceive for six months or longer
- You're over age 40
- You menstruate irregularly or not at all
- You have known fertility problems
- You've been diagnosed with endometriosis or pelvic inflammatory disease
- You've had more than one miscarriage
- You've had prior cancer treatment
If you're a man, you may wish to be evaluated sooner if you have:
- A low sperm count or other problems with sperm
- Swelling in the scrotum (see 'varicocele' below)
- You have had a previous vasectomy
- Undergone prior scrotal or inguinal surgery
- Small testicles or problems with sexual function or desire
- Had prior cancer cancer treatment
- Desire to know your fertility status
To become pregnant, the complex processes of ovulation and fertilization need to work just right. For some couples, infertility problems can be present from birth (congenital) or something can go wrong along the way that results in infertility.
The reasons for infertility can involve one or both partners. In general:
- In about one-third of cases, the cause of infertility involves only the male.
- In about one-third of cases, the cause of infertility involves only the female.
- In the remaining cases, the cause of infertility involves both the male and female, or no cause can be identified.
Causes of male infertility
Causes of male infertility may include:
- Abnormal sperm production or function due to various problems, such as undescended testicles, genetic defects, health problems including diabetes, prior infections such as mumps, trauma or prior surgeries on the testicles or inguinal region. Enlarged veins in the testes can increase blood flow and heat, affecting the number and shape of sperm.
- Problems with the delivery of sperm due to sexual problems, such as premature ejaculation, semen entering the bladder instead of emerging through the penis during orgasm (retrograde ejaculation), certain genetic diseases, such as cystic fibrosis, structural problems, such as blockage of the part of the testicle that contains sperm (epididymis), or damage or injury to the reproductive organs. Men who have previously undergone a vasectomy and desire a return of fertility will also need to either have the vasectomy reversed (see 'vasectomy reversal' below) or have sperm retrieved through a surgical procedure for use in assisted reproductive techniques.
- Overexposure to certain chemicals and toxins, such as pesticides, radiation, tobacco smoke, alcohol, marijuana, and steroids (including testosterone). In addition, frequent exposure to heat, such as in saunas or hot tubs, can elevate the testicular temperature, impairing sperm production.
- Damage related to cancer and its treatment, including radiation or chemotherapy. Treatment for cancer can impair sperm production, sometimes severely. Removal of one testicle due to cancer also may affect male fertility.
Causes of female infertility
Causes of female infertility may include:
- Ovulation disorders, which hinder or prevent the ovaries from releasing eggs. Examples include hormonal disorders such as polycystic ovary syndrome, a condition that might relate to your ovaries producing too much of the male hormone testosterone, and hyperprolactinemia, when you have too much prolactin — the hormone that stimulates breast milk production. Other underlying causes may include excessive exercise, eating disorders, injury or tumors.
- Uterine or cervical abnormalities, including problems with the opening of the cervix or cervical mucus, or abnormalities in the shape or cavity of the uterus. Benign tumors in the wall of the uterus that are common in women (uterine fibroids) may rarely cause infertility by blocking the fallopian tubes. More often, fibroids may distort the uterine cavity interfering with implantation of the fertilized egg.
- Fallopian tube damage or blockage, which usually results from inflammation of the fallopian tube (salpingitis). This can result from pelvic inflammatory disease, usually caused by sexually transmitted infection, endometriosis or adhesions.
- Endometriosis, which occurs when endometrial tissue implants and grows outside of the uterus — often affecting the function of the ovaries, uterus and fallopian tubes.
- Primary ovarian insufficiency, also called early menopause, when the ovaries stop working and menstruation ends before age 40. Although the cause is often unknown, certain conditions are associated with early menopause, including immune system diseases, radiation or chemotherapy treatment, and smoking.
- Pelvic adhesions, bands of scar tissue that bind organs after pelvic infection, appendicitis, or abdominal or pelvic surgery.
Other causes in women include:
- Thyroid problems. Disorders of the thyroid gland, either too much thyroid hormone (hyperthyroidism) or too little (hypothyroidism), can interrupt the menstrual cycle or cause infertility.
- Cancer and its treatment. Certain cancers — particularly female reproductive cancers — often severely impair female fertility. Both radiation and chemotherapy may affect a woman's ability to reproduce.
- Other conditions. Medical conditions associated with delayed puberty or the absence of menstruation (amenorrhea), such as celiac disease, Cushing's disease, sickle cell disease, kidney disease or diabetes, can affect a woman's fertility. Also genetic abnormalities can make conception and pregnancy less likely.
- Certain medications. Temporary infertility may occur with the use of certain medications. In most cases, fertility is restored when the medication is stopped.
Many of the risk factors for both male and female infertility are the same. They include:
- Age. A woman's fertility gradually declines with age and this decline becomes more pronounced in her mid-30s. Infertility in older women may be due to the number and quality of eggs as they age or to health problems that may interfere with fertility. Men over age 40 may be less fertile than younger men are.
- Tobacco use. A couple's chance of achieving a pregnancy is reduced if either partner uses tobacco. Smoking also reduces the possible benefit of fertility treatment. Miscarriages are more frequent in women who smoke. Smoking can increase the risk of erectile dysfunction and low sperm count in men.
- Alcohol use. For women, there's no safe level of alcohol use during conception or pregnancy. Avoid alcohol if you're planning to become pregnant because you may not realize you're pregnant for the first few weeks. Alcohol use increases the risk of birth defects, and it may also make it more difficult to become pregnant. For men, heavy alcohol use can decrease sperm count and motility.
- Being overweight. Among American women, an inactive lifestyle and being overweight may increase the risk of infertility. In addition, a man's sperm count and testosterone levels may be affected if he is overweight.
- Being underweight. Women at risk of fertility problems include those with eating disorders, such as anorexia or bulimia, and women who follow a very low calorie or restrictive diet.
- Exercise issues. Lack of or not enough exercise contributes to obesity, which increases the risk of infertility. Less often, ovulation problems may be associated with frequent strenuous, intense exercise in women who are not overweight.
Some types of infertility aren't preventable. But several strategies may increase your chances of pregnancy.
For couples, having regular intercourse several times around the time of ovulation offers the highest pregnancy rate. Intercourse occurring several days before and until a day after ovulation improves the probability of pregnancy. This is usually at the middle of the cycle halfway between menstrual periods for most women with menstrual cycles 28 days apart.
For men, although most types of infertility aren't preventable, these strategies may help:
- Avoid drug and tobacco use and excessive alcohol consumption, which may contribute to male infertility.
- Avoid high temperatures as this can affect sperm production and motility. Although this effect is usually temporary, avoid hot tubs and steam baths.
- Avoid exposure to industrial or environmental toxins, which can impact sperm production.
- Limit medications that may impact fertility, both prescription and nonprescription drugs. Talk with your doctor about any medications you take regularly, but don't stop taking prescription medications without medical advice.
- Exercise regularly, eat a balanced diet, and maintain a healthy weight. Obesity is directly related to testosterone levels, which is a key hormone responsible for sperm production. Eating a balanced diet provides the necessary nutrients to optimize sperm function and minimize the effects of factors which may otherwise damage sperm.
- Treating reversible causes, such as a varicocele frequently improves sperm numbers and quality and may help to prevent further loss of fertility.
For women, a number of strategies may increase the chances of becoming pregnant:
- Exercise moderately. Regular exercise is important, but if you're exercising so intensely that your periods are infrequent or absent, your fertility may be impaired.
- Avoid weight extremes. Being overweight or underweight can affect your hormone production and cause infertility.
- Quit smoking. Tobacco has multiple negative effects on fertility, not to mention your general health and the health of a fetus. If you smoke and are considering pregnancy, quit now.
- Avoid alcohol and street drugs. These substances may impair your ability to conceive and have a healthy pregnancy. Don't drink alcohol or use illegal drugs, such as marijuana or cocaine.
- Limit medications that may impact fertility. The use of some prescription and nonprescription drugs can decrease your chance of getting pregnant or keeping a pregnancy. Talk with your doctor about any medications you take regularly, but don't stop taking prescription medications without medical advice.
- Limit caffeine. Women trying to get pregnant may want to limit caffeine intake. Ask your doctor for guidance on safe use of caffeine.