Infertility - What are the factors that can increase the risk of infertility in both women and men?

Article by Dr Christopher Ng

Infertility - What are the factors that can increase the risk of infertility in both women and men?

Dr Christopher Ng

Obstetrician & Gynaecologist
Imperial College, London, United Kingdom
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What are the factors that can increase the risk of infertility in both women and men?

For healthy, young couples, the chances are about 20% that a woman will conceive in any one menstrual cycle. This figure starts to decline in a woman's late 20s and early 30s and decreases even more after age 35 years. The effect of age on men's fertility is less clear. There is a small decline in sperm numbers and motility (the ability of sperm to swim to an egg) in men over 45. But even though these characteristics are less robust than in younger men, they usually remain within normal limits until about age 70. For this reason, older couples may not want to wait 6–12 months to seek care if they are having problems conceiving.

Male factors most often involve problems with the amount or health of the sperm. Abnormal hormone levels may be a cause. Infection or scarring from a sexually transmitted disease (STD) also may be a cause. Female factors also may involve abnormal hormone levels. The ovaries may not produce enough eggs at the right time (anovulation). Scarring or blockages in the cervix or tubes also may be a cause. Lifestyle factors, such as poor nutrition, anorexia, and obesity can play a part in infertility. Other health problems also can play a role (diabetes, thyroid problems).

Infertility seems to have taken on “national” urgency. How does a couple determine if they are capable of conception?

Infertility is defined as the inability to conceive after 1 year of having regular intercourse without using contraception. About 15% of couples are infertile and this number is increasing as more and more couples are delaying starting their family. If a couple has been trying unsuccessfully for more than a year then they should see a gynaecologist to get investigated for possible causes for their infertility. However as the risk of genetic disorders, miscarriage and infertility increase with increasing age, women who are over 35 years old and have been unsuccessful may wish to seek medical help after 6 months of contraceptive-free intercourse for these very reasons. Infertility may be caused by more than one factor. Some are easy to find and treat, while others are not. The factor may relate to the woman or the man. In some cases, no cause can be found in either partner.

How do you test or diagnose infertility? Is the problem gender-specific?

Infertility affects both men and women. The decision to begin testing depends on a number of factors. They include woman’s age and her partner's age, as well as how long they have been trying to get pregnant. Testing involves an evaluation as follows:

  • Physical exam
  • Medical history
  • Semen analysis
  • Ovulation check
  • Tests to check for a normal uterus and open fallopian tubes
  • Discussion about how often and when you have sex

Basic Tests for the Man

A semen analysis is a key part of the basic workup for a man. It may need to be done more than once. The semen sample is obtained by masturbation and is analysed for:

  • Number
  • Shape
  • Movement
  • Signs of infection

Basic Tests for the Woman

The investigation for a woman begins with a physical exam and health history. The health history will focus on key points:

  • Menstrual function, such as irregular bleeding and pain
  • Pregnancy history
  • STD history
  • Birth control

There are many tests to see if ovulation occurs. These include:

  • Urine test. This test can be done by the woman at home with a kit. It is a way to predict ovulation. This test measures a rise in luteinizing hormone (LH) indicating that ovulation has occurred.
  • Basal body temperature. This test can be done by the woman at home. It is a way to tell that ovulation has occurred. After a woman ovulates, her body temperature increases a bit. To measure it, a woman takes her temperature by mouth every morning before she gets out of bed (basal temperature). She records it on a chart for two or three menstrual cycles. Other tests may be done, depending on a woman's risk factors.
  • Serum progesterone. This is a timed blood test performed at a specific time during a woman’s menstrual cycle to determine if she has ovulated.


Procedures are used to look at a woman's reproductive organs. They check if the uterus is normal and the fallopian tubes are patent.

  • Hysterosalpingography (HSG). This test is an X-ray that shows the inside of the uterus and fallopian tubes. In most cases, it is done right after a menstrual period. A small amount of dye is placed in the uterus through a thin tube inserted through the cervix. An X-ray is then taken. The dye outlines the inside of the uterus and fallopian tubes. If it spills from the tubes, it shows that the tubes are patent.
  • Transvaginal ultrasound. This test checks the ovaries and uterus by using sound waves to produce pictures of pelvic organs. First a device (a transducer) shaped like a wand is lubricated and inserted into the vagina. A machine displays an image of the organs.
  • Hysteroscopy. This procedure lets the doctor look inside the uterus. A thin telescope-like device, called a hysteroscope, is placed through the cervix. The uterus may be filled with a gas or liquid to reveal more information. During this procedure, the doctor can correct minor problems or get a sample of tissue to study. The doctor also may decide other procedures are needed.

Laparoscopy. This procedure lets the doctor view the tubes, ovaries, and the outside of the uterus. A small telescope-like device, called a laparoscope, is inserted through a small cut in the navel. Fluid is placed in the uterus to see if it spills from the ends of the tubes. This shows if the tubes are patent or blocked. The doctor also can look for pelvic problems, such as endometriosis or scar tissue. 

Would you advise couples to go for fertility screening before they get married?

It is assumed that most couples are fertile so long as they do not have any medical problems so preconception testing for infertility is not necessary unless the couple may have some reasons to suspect that they may encounter difficulties in conceiving. 

Some people believe that diet and the types of food consumed can affect fertility. What’s your advice?

Eating healthy food and staying well nourished increases your odds of conceiving. Make sure to include enough protein, iron, zinc, and vitamin C, because deficiencies in these nutrients have been linked to decrease fertility and a higher risk of early miscarriage. Generally speaking a well balance diet along with regular exercise and reduce stress also help to increase a couple’s chances of successfully conceiving.

Avoiding alcohol and reducing caffeine intake certainly helps as alcohol consumption decreases the ability to get pregnant (not to mention the harm it can cause to a developing foetus). Cutting back on caffeine while you try to conceive and during your pregnancy is encouraged as high caffeine consumption can increase the risk of miscarriage.

Quit smoking because aside from health concerns, cigarette toxins can damage a woman's eggs, interfering with the fertilization and implantation process.


Disclaimer: Health articles posted at are provided for information purposes only and reflect the views of the respective authors. They do not necessarily represent endorsement by or an official position of Advice on the treatment or care of individual patients should be obtained through consultation with a physician who has examined that patient and is familiar with that patient's medical history.