Why can't I fall pregnant again?

secondary infertility is a big issue for many moms
secondary infertility is a big issue for many moms

Having successfully conceived and delivered a child before does not mean that you are necessarily fertile. Many physical, emotional and lifestyle changes after a first child can affect the chances of falling pregnant again.

If you’ve been unable to conceive after a year of unprotected and appropriately timed intercourse, and one or both partners have previously conceived children, you will officially be diagnosed as suffering from secondary infertility. So what are the primary causes of secondary infertility?

Causes of secondary infertility

You're over 35

Fertility peaks in your mid-20s to early-30s and decreases quite significantly at 35 and again after 40. By the time you are 45, your chances of falling pregnant naturally is as low as 6% per cycle.

All women are born with all the oocytes (eggs) they will ever have. The older they are, the more they will have been exposed to environmental factors that can decrease their quality or even cause subtle gene mutations. Poor quality eggs may fertilise but spontaneously abort before you even realise you are pregnant.

While 35 may be the magic number we all work around, fertility should become a consideration when planning your second baby. “The onset of a decline in fertility starts in the early 30s,” says Dr Silke Dyer, head of the Reproductive Medicine Unit Department of Obstetrics and Gynaecology at Groote Schuur Hospital. “If you fell pregnant easily in your early 30s, you can’t assume the same thing will happen with your next child in your late 30s.”

The quality/quantity of sperm

Women are quick to blame themselves for infertility but there is a real chance that the problem could lie with their partner. Recent studies have shown that the quality and quantity of sperm also begins to decline after the age of 35.

Problems can also occur as a result of stress, illness, injury and/or environmental factors, says Dr Colin La Grange of the Life Institute.

Blockage in the semen-delivery system can also be a factor. In some cases, men have immune-system disorders, which cause their bodies to develop antibodies to their own sperm, which attack and weaken the sperm. The antibodies can also attach to the sperm surface and interfere with their movement or ability to fertilise the egg.

"A decline in libido and frequency of intercourse may also be a factor here," says Dr Dyer.

The couples factor (it's both of you)

While you might have fallen pregnant easily with one partner, it doesn’t mean the same thing will happen with another. It’s not uncommon for couples who remarry and try for a “second family” to encounter problems.

You're no longer ovulating

In about 30% of cases of secondary fertility anovulation is the culprit. "Causes include polycystic ovarian syndrome [PCOS], birth control pills, chronic physical illness, extreme changes in weight, prolonged extreme exercise, and high levels of prolactin, TSH and thyroid hormones," says Dr La Grange.

“Using the Chinese system, I see anovulation as a deficiency response in blood, Qi and yang, with lowered levels of hormones or a poor hormone response. Acupuncture, Network Spinal Analysis, reflexology and nourishing, supportive herbs are paramount to the success of the ovulation occurring on time,” he says.

If you suffer from PCOS but conceived easily with your first pregnancy, weight gain is probably a factor. "You might have put on weight in your mid to late 40s so you stopped ovulating. But, studies have shown that even minor weight loss can restore ovulation," says Dr Dyer.

While most women experience menopause in there 40s and beyond, it can hit you in your 20s and 30s. This is called premature ovarian failure.

Conception is being interrupted

Your egg and your partner’s sperm might be perfectly healthy, but unless they meet and fuse in an ideal environment, you will not fall pregnant. Your fallopian tubes – a minute “passage” along which your fertilised egg must travel to reach your uterus – may have become blocked after your first pregnancy.

Tubal damage is responsible for about 15% of cases of secondary infertility and as many as 25% in African countries. There are many causes including adhesions caused by a Caesarean section, pregnancy complications, infections, pelvic inflammatory diseases, scar tissue, fibroids (tissue growths in the uterus wall) and endometriosis.

A blocked tube hinders a pregnancy by preventing the egg and sperm from meeting. Blocked tubes also increase your risk of an ectopic pregnancy.

Another factor that could cause infertility for women with endometriosis may be the over-production of hormones called prostaglandins, which play an important role in the fertilisation and implantation of the embryo.

“With mild damage surgery may be an option to restore fertility but for more severe cases your most effective option is IVF,” says Dr Dyer.

It's a hostile environment

Hormonal changes can affect the consistency of your vaginal mucus. If it becomes too thick or sticky even healthy sperm will have trouble swimming up through the cervix to meet your egg in the fallopian tubes.

Your lifestyle has changed

Changes to your body-fat percentage can interfere with ovulation. Putting on significant weight or rapidly losing it can both lead to secondary infertility. If you’ve picked up a smoking habit or increased your intake of alcohol since your last pregnancy, this could also be a factor.

You've had an STI

The worrying rise in HIV figures in married women or those who are in monogamous relationships mean that we can’t always be sure what our better half has been up to. Even if you have remained faithful, your partner could have given you a sexually transmitted disease that you were unaware that you had contracted: gonorrhea and chlamydia are the most common.

Up to 40% of women with untreated chlamydia develop pelvic inflammatory disease. If this is left untreated infection can spread into the uterus or fallopian tubes and cause permanent damage. "Studies have also shown that HIV can affect sperm quality and lead to an increase in early pregnancy loss," says Dr Dyer.


While many doctors dismiss the link between stress and fertility, most alternative practitioners believe it is an important factor as the release of cortisol (the stress hormone) can wreak havoc with your body’s delicate hormonal balance.

“The more we stress, the more cortisol we produce and the less fertile we become as cortisol steals the progesterone needed to make adequate oestrogen and testosterone. This stress cycle results in a range of hormone and sugar imbalances, all of which wreck havoc on the body’s reproductive processes,” says Dr La Grange.

“Ruling out any major pathology, I believe that one of the key causes of secondary infertility is stress, which is a culmination of daily habits, poor diet, lack of sleep and exercise, incorrect breathing, and emotional upset.”

"To increase your chance of conceiving naturally, you need to make a number of lifestyle choices or changes. These need to include a low GI diet, particularly avoiding wheat and sugar; breathing from the diaphragm rather than shallow chest breathing, getting earlier to bed for a minimum of 7 hours sleep, and spending more time honouring your needs and taking time for yourself.  

"However, not all people are in control of their stress", says Dr Dyer. "I tell patients not to be stressed about being stressed. We often recommend a fertility sabbatical where people take 3 months off trying to conceive," she says.

To read an inspiring story about how a mother overcame secondary infertility, go to "Overcoming secondary infertility"

To find out what tests can be done if you are suffering from secondary infertility, go to page 2


What tests can be done?

If you are suffering from secondary infertility, your doctor may attempt to get to the bottom of it by doing the following tests as deemed necessary:

A Day 21 blood test

Taken 21 days since the start of your last period (if you have a 28-day cycle), this test will measure the levels of the hormone progesterone in your blood to determine if you are ovulating. A level of 30nmol/l or more suggests ovulation has occurred.

A Day 3 blood test:

The levels of FSH (follicle stimulating hormone) and oestrogen will diagnose PCOS or premature ovarian failure, indicating follicle quality and ovarian response.

Thyroid function and prolactin tests

If a woman has irregular or infrequent menstrual cycles, or shows other signs of thyroid disease, then it’s important to exclude this.

Prolactin is a hormone that is normally involved in the production of breast milk and is released from a gland in the brain called the pituitary. An overactive pituitary gland can cause abnormally high levels of prolactin, which prevents ovulation.

Stress levels can also be elevated by too much prolactin and prolactin can inhabit ovulation.


Depending on the results of your blood tests, an ultrasound may be performed to confirm the existence of cysts on your ovaries that indicate you have PCOS. “A well done ultrasound can pick up a lot,” says Dr Dyer. “This includes fibroids, endometriosis and even a blocked tube if it has swelled up.”

Sperm analysis

Before any invasive tests are performed, it is wise to get your partner’s sperm tested. If the results indicate problems, you may be asked to repeat the test again.

Hysterosalpingogram (HSG)

The HSG test X-rays the uterus and fallopian tubes after dye is injected into your uterus. The dye travels through the tubes and will show any damage, abnormalities or blockages. It will also highlight the shape of your uterus. HSGs can reveal tubal blockages and, though uncomfortable, are less invasive than a laparoscopy.


This allows your doctor to look inside your womb using a narrow tube-like telescope passed through the vagina and cervix, and into your womb. It can diagnose fibroids or abnormalities in the shape or structure of the womb or be used to remove polyps and scar tissue.


Investigative surgery using a viewing instrument inserted through an incision below your belly button will look for damage and abnormalities in your reproductive system. If an HSG indicates there may be a blockage in your fallopian tubes, dye will also be injected into your tubes to confirm this.

A post-coital test

Similar to a pap smear, this test examines the mucus around the cervix shortly after intercourse. The interactions between the sperm and cervical mucus are analysed under a microscope.

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