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Struggling with infertility is not uncommon. Singapore has one of the lowest total fertility rates in the world at 1.2 per female in 2011. Women are starting families later due to education, work, family commitments or inability to find a suitable spouse earlier in life. The average age of first time mothers is now 30 years old. Subfertility can be very stressful and may come as a surprise since many women have no complaints until they try to conceive. Even when it ends with a healthy baby, the journey can exact a toll. 

Singapore has one of the lowest total fertility rates in the world at 1.2 per female in 2011. Click To Tweet

Most of us grow up believing that we can start a family when we are ready, but this is not often the case. A recent poll of 1000 respondents in Singapore found that more than half knew someone struggling for a first or second child.

Among the usual obstacles couples face are long work hours and job stress, which leave them too tired or not in the mood to have sex. However, apart from infrequent intimacy, there are also physiological factors that may negatively affect female fertility.


Medically, a woman is considered subfertile if she is unable to conceive after 12 months of trying naturally. If the woman is over the age of 35, she would be regarded as subfertile if she has not conceived after 6 months of trying. In about a third of subfertility, the cause is primarily female, in another third, the cause is male factor ( sperm abnormalities) while the remainder is a combination of both. 

To understand this struggle, here are 10 of the common reasons for infertility in women. 

1. Endometriosis

This is a condition in which tissues similar to your uterine lining grow elsewhere in the body. It can develop outside the uterus, tubes, ovaries, and even in the bladder or intestines. It may significantly lower the chance of getting pregnant in those who have the condition. Patients classically complain of painful periods, painful intercourse or painful bowel movements and urination. 

Endometriosis can trigger fertility issues in several ways such as scarred fallopian tubes, adhesions, distorted pelvic anatomy, inflamed pelvic structures, and impaired implantation. It can even alter your egg quality and ovulation. 

Through laparoscopy, the doctor can assess the amount, location, and depth of endometriosis then treat it. From these laparoscopic findings, your condition can be graded according to severity. This scoring system correlates to your chances of getting pregnant. Women who fall under severe (stage 4) have the most difficulty conceiving and will require extensive fertility treatment. If there are endometriotic cysts or deposits, these can be removed during laparoscopy and an assessment for fallopian tube patency (hydrotubation) can be performed concurrently.

2. Failure to Ovulate

Ovulation is when your ovaries release an egg—a process that is essential for pregnancy to be achieved naturally. However, there are cases where a woman does not ovulate (anovulation), or ovulation occurs irregularly (oligo-ovulation). If this seems familiar to you, know that ovulatory disorders are one of the common reasons women find it hard to conceive. 

A woman may fail to ovulate due to hormonal problems which are linked to malfunctions in the hypothalamus or pituitary gland or diminishing ovarian reserve as a result of ageing. In other cases, it is also linked to ovarian or gynaecological conditions such as polycystic ovarian syndrome (PCOS) or primary ovarian insufficiency (POI). Furthermore, scarred ovaries from previous surgeries, premature menopause, lifestyle, and environmental factors are also potential causes. 

An indicator of ovulatory dysfunction is when your menstrual cycles are shorter than 21 days, or longer than 36 days. It’s still possible for those whose cycle falls within the normal range of 21 to 36 days, but the length may vary every month. 


3. Primary Ovarian Insufficiency (POI)

It is expected that women in their 40s have a lower fertility rate. It is usually around this age where your body starts transitioning to menopause, often characterised by irregular menstrual periods. However, for women with POI, the process starts even before they reach 40, sometimes as early as their teenage years.

This is slightly different from premature menopause when periods stop before you hit 40. In such a case, you can no longer get pregnant. But, with POI, some women can still have occasional periods, giving them a 5 percent to 10 percent chance of getting pregnant even without medical intervention. 

In most cases, the cause of POI is unknown. But it has been linked to chromosomal abnormalities like Turner’s syndrome, autoimmune conditions and previous chemoradiation therapy.

4. Polycystic Ovarian Syndrome (PCOS)

PCOS is one of the most common causes of infertility among women of reproductive age. But having it doesn’t mean you can never conceive because PCOS is treatable. This condition is associated with hormonal imbalance due to the overproduction of androgens. Excess levels of these interfere with the development of ovarian follicles, which results in the formation of fluid-filled sacs or cysts. Hormonal fluctuations also interfere with the growth and release of eggs from the ovaries. Patients have abundant egg follicles but they do not mature and ovulate hence pregnancy chance is reduced.

Normally, a woman releases an egg (ovulate) 14 days before her menstrual period. But, if you have irregular cycles, it may be difficult to predict ovulation and time the intercourse. 

5. Malfunction of the usual hormonal (hypothalamo-pituitary-gonadal) axis

In the brain, the hypothalamus sends hormonal signals (Gnrh) to the pituitary gland to release the hormones FSH and LH that control the stimulation and maturation for eggs to develop in the follicles of the ovary. If there is a failure of the brain to control this process, the egg will also fail to mature and will be unable to get released. Stress is one common reason for delayed periods because of non-ovulation during the cycle. Increase in cortisol (stress hormone) suppresses the reproductive hormonal axis in favour of survival ( flight or fight response). It is evolutionary that the body will reduce reproductive potential when experiencing stresses like illness, malnutrition, chronic fatigue, excessive physical toll like heavy exercise, or emotional turmoil like anxiety or depression as it will be perceived as an incompatible time to carry a fetus. 

6. Reproductive Tract Infection

Reproductive tract infections are among the causes of subfertility in women, especially those that manifest no symptoms. 

Untreated infections like gonorrhoea and chlamydia can cause scarring that can block the fallopian tubes. Bacterial vaginosis is an infection that causes a bacterial imbalance in a woman’s vagina, and may even affect IVF results. Furthermore, if you get pregnant with untreated syphilis, you have a 50 percent chance of a miscarriage or stillbirth. 

Meanwhile, chronic vaginal infections can also reduce the amount or quality of mucus and natural lubrication making intercourse uncomfortable and patients unkeen for intimacy.. 

7. Structural Abnormalities of the Reproductive System

In some instances, structural issues to your reproductive system can also be a contributing factor to infertility. For example, a blocked fallopian tube due to endometriosis can impede fertilisation. In the same way, scarring or adhesions on the uterus caused by injuries, infection, or surgery can obstruct implantation, which can also lead to infertility. 

Uterine fibroids, which are growths that can potentially distort the uterine cavity, also play a significant role in infertility depending on their size and location. Polyps, which are also non cancerous growths in the uterine lining, may prevent the successful implantation of a fertilised egg. 

Sometimes, the uterus and fallopian tubes may not form as they should, and an unusually shaped uterus (congenital malformation) can also be a problem. While this usually goes unnoticed, it can affect implantation or a woman’s ability to carry a pregnancy to term. Some types of congenital abnormalities like septums can be resected with surgery.

8. Uterine Fibroids


Uterine fibroids are noncancerous growths that form inside the uterus, which can reduce fertility in a variety of ways. First, fibroids can potentially change the shape and size of the uterus. Consequently, it may affect the cervix and the number of sperm that enters the uterus. This structural change can also interfere with the movement of the sperm or embryo. Second, fibroids may block Fallopian tubes or impair implantation. Third, these growths can also interfere with blood flow to the uterus, which can hamper the implantation of the embryo. 

Fibroids located in the uterine cavity (submucosal) or push into the cavity (intramural type III) are more likely to cause fertility issues and miscarriages. This is particularly true for growths that are larger than five centimetres. 

Scientists do not know what triggers fibroid formation but it is believed that genetics, hormones, and environmental factors all play a role. 

Read: A Beginner’s Guide on Fibroid Treatments in Singapore

9. Impaired implantation

Apart from anatomical causes preventing implantation, there may also be impaired functioning of the endometrium. A thin endometrium at the time of implantation and poor receptivity may affect the ability to conceive. There are some studies linking immunological factors or antibodies (thrombophilias) to poor receptivity but interventions like IV Ig, steroids, or aspirin are still controversial. 

10. Autoimmune Disorders

Autoimmune disorders occur when your body’s immune system malfunctions, setting off an inflammatory response aimed at healthy tissues. Women with an existing autoimmune disease, including rheumatoid arthritis, diabetes, systemic lupus erythematosus (SLE), or Crohn’s disease, may be at higher risk of infertility. The reason is not fully understood and may differ between diseases, but it is believed that inflammation in the uterus and placenta, or medications used to treat the disease, may have a hand in this. 

Investigating Possible Causes of Female Subfertility

A subfertility evaluation may be prescribed to a woman who, by definition, has subfertility or has a high risk. This process involves a comprehensive medical history, a targeted physical examination (e.g vital signs, thyroid, breast, pelvic examination), ovarian tests  (e.g. ovarian reserve, ovulatory function, structural abnormalities), and imaging of reproductive organs. 

A subfertility evaluation may be prescribed to a woman who, by definition, has subfertility or has a high risk. Click To Tweet

In women, tests may be conducted to check blood and urine. One can tell from a urine LH kit analysis when and if you have ovulated. Meanwhile, blood tests that may be ordered will measure: 

  • ovarian reserve (egg supply) 
  • progesterone levels (to check if you have ovulated) 
  • thyroid function (thyroid issues may cause infertility)
  • your levels of prolactin (high levels disrupt ovulation)

To check structural issues, these are the usual imaging tests and surgical procedures involved in female infertility: 

  • Ultrasound – It can view changes to the follicles and help predict when ovulation will occur as well as rule out polyps, fibroids and congenital malformations.
  • Hysterosalpingography – It is an x-ray procedure that investigates the shape of the uterine cavity, as well as the shape and patency of the fallopian tubes.
  • Laparoscopy – It involves the use of a device called a laparoscope, which comes with a camera and a thin light source. It is inserted through the umbilicus and into the abdominal cavity to view internal structures such as the fallopian tubes, ovaries, and the outside of the uterus. 
  • Hysteroscopy – It involves a device with a camera and a thin light source, inserted through the vagina into the cervix and into the uterus. It can explore the internal structures and show any abnormal intrauterine structures. 

How is Female Infertility Treated? 

Medication is among the common interventions for female infertility. Often, medication is prescribed to correct ovulation problems. Some are formulated to trigger ovulation while others stimulate the ovaries to release multiple eggs. There are also drugs that can help those who struggle with unexplained infertility and serve as a therapeutic option for those who didn’t find success in other treatments. 

Laparoscopy is a minimally invasive procedure that can remove fibroids or endometriotic lesions and scar tissue, unblock a fallopian tube, or reverse tubal ligation—all of which can help increase the chances of conceiving. 

Hysteroscopy. In this procedure, your doctor places a hysteroscope into your uterus through your cervix. It is used to remove polyps and fibroid tumours, divide scar tissue, remove congenital septums and open up blocked tubes.

Intrauterine insemination (IUI) is a procedure where the semen is prepared and inserted into your uterus around the time you’re ovulating. It is occasionally done along with pharmacologic interventions that help stimulate the release of an egg (SO-IUI).  

In vitro fertilisation (IVF) is a form of treatment that uses assisted reproduction technology (ART) to help couples struggling with conceiving. It is a combination of medications and surgical procedures where the ovaries are stimulated to produce a large number of mature eggs that are extracted under sedation. Sperm and an egg are put together in a petri dish and fertilised in the lab. The grown embryo is then implanted into your uterus 3-5 days later. If both partners agree, extra embryos can be frozen and saved for future use. 

An IVF is considered for the following reasons:

  • A woman’s fallopian tubes are blocked or missing
  • A woman has severe endometriosis
  • There is unexplained infertility for a long time 
  • Intrauterine insemination has not been successful 
  • A man has a low sperm count, poor sperm quality, and low sperm quantity

Another ART option is ICSI (intracytoplasmic sperm injection) which is similar but specifically caters to sperm-related infertility problems. In this procedure, the lab technician injects a chosen sperm directly into the egg instead of allowing natural fertilisation of the sperm and egg placed in a dish and this improves the rate of fertilisation of the egg and development into an embryo. 

Egg donation is also another option when your ovaries fail or you are above 40 yr with poor ovarian reserve but you have a normal uterus. The process involves retrieving eggs from a consenting donor with normally functioning ovaries. After in vitro fertilisation, your doctor transfers the fertilised eggs into your uterus.

Surrogacy to overcome uterine factors for subfertility is illegal in Singapore. Many patients opt to seek commercial surrogacy services overseas eg USA. 

With all that, now you realise that while there are several reasons behind female infertility, there is also a gamut of treatments to address it. What’s important is that you take the first step as soon as possible because when it comes to fertility, age is a critical factor and time is of the essence.

So, seek the right help. With what you know now, ask the right questions during a consultation. If you have any concerns, Dr Pamela Tan provides customised care for all your obstetric and gynecologic needs. Send us a message if you wish to schedule an appointment today!

Dr Pamela Tan
About Dr Pamela Tan

Dr Pamela Tan is a board certified obstetrician and gynecologist in Singapore. She finished her undergraduate studies at the National University of Singapore and earned her post-graduate degree at the Royal College of Obstetricians and Gynaecologists in the UK. She is an accredited specialist by the Specialist Accreditation Board (Ministry of Health), and a fellow of the Academy of Medicine, Singapore. She subspecialises in colposcopy and is certified to perform Level 3 minimally invasive keyhole surgeries such as laparoscopic hysterectomy, myomectomy and cystectomy. Dr Pam also supports the natural birthing method and she strives to provide a personalised care and treatment for each patient.