Source: Dr Tan Thiam Chye, Dr Tan Kim Teng, Dr Tan Heng Hao, Dr Tee Chee Seng John, The New Art and Science of Pregnancy and Childbirth, World Scientific 2008.

How Does a Pregnancy Happen?

Conception can only happen when a sperm swims up into the womb before fertilising an egg in the fallopian tube. This allows the fertilised embryo to implant or embed itself into the womb lining, where it will grow into a foetus.

Related: Conception to Birth: Eating for a Healthy Baby

Am I Subfertile?

There is indeed a possibility that something is wrong in you or your partner if you are still not pregnant after a period of trying to conceive. An average couple in their 30s will conceive after about 6 months of trying to do so.

Certainly, any couple that fails to conceive after a year of trying should seek prompt medical attention, so that the appropriate investigations and treatment can be carried out.

In our current climate of a hectic schedule, it is important to note that regular sexual intercourse of two to three times per week should be happening between the couple before they can be labelled as subfertile.

The most fertile period is usually two weeks before the onset of a women’s period if she has a regular cycle. This is when the egg is released from the ovary into the fallopian tubes.

Related: Sexual Positions and Timing of Conception

What Can Possibly Be Wrong?

It is important to remember that subfertility is never the fault of any one individual. There are varying factors that could contribute to a couple not being able to conceive.

For a start, one must exclude male or female sexual dysfunction, whereby the sexual act is never carried out anyway. This can lead to a breakdown of the relationship in the long run.

There can be many reasons for male sexual dysfunction and an inability to ejaculate.

They include:

  • Impotence

  • Erectile Dysfunction

  • Diabetes

  • Prostate Surgery

  • Chronic Usage of Medications, e.g. Anti-Hypertensives

In the female, vaginismus or pain during sexual intercourse is perhaps the most common cause of female sexual dysfunction.

Various tests may be carried out to further investigate underlying causes. They include:

  • A sperm analysis to look out for any sperm abnormalities.

  • Hormonal blood tests to confirm ovulation.

  • Radiographic tests such as a pelvic ultrasound scan to assess for womb problems or growths. A hysterosalpingogram, that involves the X-ray of the pelvis after passing of a dye contrast into the womb to assess the patency of the fallopian tubes, can also be performed.

  • A key-hole surgical survey of the womb cavity (via hysteroscopy) and the fallopian tubes (via laparoscopy) can also be performed and any gynaecological problems may be treated at the same time.

In 20 percent of couples, no identifiable causes can be found (idiopathic subfertility). In such cases, treatment is only empirical and assisted reproductive techniques (ARTs) such as intrauterine insemination or in-vitro fertilisation (test-tube baby) can be employed to help the couple conceive.

In the remaining 80 percent, problems can be divided into female factors, male factors or a combination of both.

Related: Sexual Positions and Timing of Conception

Female Factor Subfertility

In the female, any factor that prevents the sperm from reaching the egg (ovum) in the fallopian tube will result in subfertility.

Anovulation (Failure of the Ovaries to Produce an Egg)

This commonly results from stress, excessive weight loss or exercise, poor nutrition, chronic medical conditions, inherent ovarian problems such as polycystic ovarian syndrome or previous ovarian surgeries. They usually manifest as an absence, delay or irregularity in the menses.

Fallopian Tube Blockage

Even if an egg is released, blocked fallopian tubes can still prevent fertilisation from happening. These may result from previous genital infections, tubal surgeries, endometriosis or pelvic adhesions.

Womb or Cervical Mucus Defects or Abnormalities

These can prevent fertilisation or implantation, resulting in subfertility. Large fibroids, especially those disrupting the womb cavity, have been known to be associated with an inability to conceive.

Womb adhesions (Asherman Syndrome) resulting from previous surgeries or instrumentations will result in the obliteration of the entire cavity and prevent subsequent conception. Congenital defects such as septum or abnormal womb structure can contribute to this problem as well.


This is a very common gynaecological condition amongst women in the reproductive age group. It is characterised by the implantation of the womb lining tissue in the abdomen or the pelvic cavity.

Menstrual pain and subfertility are the most common symptoms that can affect these women. In severe cases, it can disrupt the fallopian tubes and cause tubal blockage. However, even mild cases have been known to be associated with subfertility and the surgical removal of these deposits can result in an improvement of the fertility.

Male Factor Subfertility

Abnormal sperm parameters can include:

  • Low sperm count (Oligospermia)

  • A lack of sperm (Azoospermia)

  • Abnormal sperm shape (Teratozoospermia)

  • A lack of sperm motility (Asthenospermia)

There are many underlying factors that may contribute to the above. Prolonged heat exposure may reduce sperm potency, hence explaining the rationale of avoiding tight undergarments.

Various other possible underlying causes of poor sperm quality or low counts include:

  • Alcoholism

  • Recreational drug abuse

  • Environmental toxins

  • Long-term usage of certain medications

More commonly, problems may exist in the testicles or testicular ducts, and these affect sperm production.

The testicular problems include:

  • Varicocele (engorged blood vessels surrounding the testes)

  • Undescended testes (even if successfully treated in infancy)

  • Previous testicular infections (such as mumps)

  • Previous testicular or hernia operations.

Testicle duct blockage affects sperm delivery and this can be due to testicle duct scarring (from previous sexually transmitted infections) or an inherent genital tract abnormality.

Related: Benefits of Quitting

Frequently Asked Questions

1. When and why should I seek medical attention if I am unable to conceive?

Any couple who cannot conceive after 12 months of regular sexual intercourse should seek immediate medical attention. It is preferable that both the partners see their doctor together so that the appropriate investigations and counselling can take place.

We advise women aged 35 years and above to seek medical attention urgently as the treatment success is lower in older women.

Related: Pre-Pregnancy Preparations

2. What can be done for subfertility?

Depending on the underlying causes, varying treatment modalities may be offered. In cases of anovulation, drugs that enhance ovulation e.g. clomiphene may be prescribed to help the couple conceive. This can result in minor side effects such as nausea and bloatedness, multiple pregnancies (5 to 10 percent chance of twins) and may increase the risk of ovarian cancer in cases of prolonged and unregulated usage. Therefore, clomiphene is usually prescribed for only six ovulatory cycles.

Laparoscopic (key-hole) surgical interventions can also be used to treat tubal blockages, uterine abnormalities, fibroids or endometriosis.

Assisted reproductive techniques (ARTs), such as intra-uterine inseminations or in-vitro fertilisations (test tube babies), may be employed by reproductive specialists in certain cases.

In cases of severe male factors, intra-cytoplasmic sperm injection (ICSI) can be used. This refers to the injection of a single sperm to fertilise the egg. All these can only happen after detailed counselling of the procedural risks and benefits.

In the most extreme cases or for those adverse to assisted reproductive programmes, child adoption can even be considered as a last resort.

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