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Dr Pamela Tan is an obstetrics and gynaecology specialist practising at Thomson Medical Center in Singapore. Prior to leaving for private practice, Dr Tan was a female Consultant in the Department of Obstetrics and Gynecology, KK Women’s & Children’s Hospital.

She obtained her undergraduate medical degree at the National University of Singapore and her post-graduate MRCOG in London at the Royal College of O&G. She is a specialist accredited with the Specialist Accreditation Board (Ministry of Health) and is a Fellow of the Academy of Medicine, Singapore (FAMS). She is an accredited member of the Society for Colposcopy and Cervical Pathology of Singapore (SCCPS) with a subspecialty interest in colposcopy (for pre-cancer of the cervix and vagina) and vulval disease.

In further pursuing this interest, she was a fellow for pre-invasive disease at the colposcopy and vulval unit at the Whittington Hospital in the United Kingdom. 

While in the United Kingdom, she was also a fellow at the Assisted Conception Unit in Guys Hospital to learn the latest in reproductive techniques and approaches to infertility. She is accredited to perform advanced Level 3 minimally invasive keyhole surgery such as laparoscopic hysterectomy, myomectomy and cystectomy (womb, fibroids and cysts removal).

Her philosophy to doctoring is one that is focused on building relationships with her patients. She strives to deliver patient care that is warm, caring, professional and well advised. She is a believer of pro natural birthing and providing an optimal birthing experience as desired by her patients.

Dr Pamela Tan is an obstetrics and gynaecology specialist practising at Thomson Medical Center in Singapore. Prior to leaving for private practice, Dr Tan was a female Consultant in the Department of Obstetrics and Gynecology, KK Women’s & Children’s Hospital.

She obtained her undergraduate medical degree at the National University of Singapore and her post-graduate MRCOG in London at the Royal College of O&G. She is a specialist accredited with the Specialist Accreditation Board (Ministry of Health) and is a Fellow of the Academy of Medicine, Singapore (FAMS). She is an accredited member of the Society for Colposcopy and Cervical Pathology of Singapore (SCCPS) with a subspecialty interest in colposcopy (for pre-cancer of the cervix and vagina) and vulval disease.

In further pursuing this interest, she was a fellow for pre-invasive disease at the colposcopy and vulval unit at the Whittington Hospital in the United Kingdom. 

While in the United Kingdom, she was also a fellow at the Assisted Conception Unit in Guys Hospital to learn the latest in reproductive techniques and approaches to infertility. She is accredited to perform advanced Level 3 minimally invasive keyhole surgery such as laparoscopic hysterectomy, myomectomy and cystectomy (womb, fibroids and cysts removal).

Her philosophy to doctoring is one that is focused on building relationships with her patients. She strives to deliver patient care that is warm, caring, professional and well advised. She is a believer of pro natural birthing and providing an optimal birthing experience as desired by her patients.

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The Fertility Drugs and Supplements That Help Set The Stage for Conception

When your efforts to conceive is turning out to be an uphill climb, seeking the right professional help and treatment is the next sensible thing to do. Fertility drugs are the most commonly used infertility treatments for women, either to help them ovulate, address reproductive health issues, or to prepare their bodies for artificial insemination.

In this blog, we are going to take a quick look at how these medications help women produce eggs and set the stage for conception. Treatment can vary in women, and it could involve oral medication or injections. In addition to that, supplements also play an essential supportive role in the process. 

The Benefit of Fertility Drugs

Fertility medications are used for three purposes:

  • To get women to ovulate (ovulation) 
  • To increase the number of eggs in women who do ovulate (More eggs)
  • In preparation for IVF 

When you seek medical interventions for infertility, there is a hierarchy of treatments where fertility drugs come first. Of course, you wouldn’t want to jump right into surgical measures or IVF when your reproductive issues can still be addressed through less invasive solutions.

Furthermore, medications are not new to the market and have long been proven to work. However, these products are not magic pills that can leave you sprouting offspring. It comes with proper advice from a certified OB or a fertility specialist. 

Ovulatory Medications

To induce ovulation, oral medications are prescribed first since they are less expensive, easier to use, and they don’t require as much monitoring. Click To Tweet

To induce ovulation, oral medications are prescribed first since they are less expensive, easier to use, and they don’t require as much monitoring. However, a step above that are injectables, which are also proven treatments that aid in ovulation. Let’s go through these options to learn what to expect. 

Oral Medications 

When it comes to oral fertility medications, two names are considered as standard treatments. Clomid was the first to come out in the market in 1967 and has been the most commonly used fertility medication in history. Letrozole entered the scene in 1996 – almost 30 years after Clomid. It was initially used as a breast cancer treatment and has only been prescribed as a fertility medication since 2001.



Clomid has been the drug of choice for women with anovulatory infertility and unexplained infertility. It binds to estrogen receptors and triggers the pituitary gland in the brain to release an increased amount of Follicle Stimulating Hormone (FSH) and Luteinising Hormone (LH). These two hormones help stimulate the growth of an ovarian follicle which contains an egg that will be ready for fertilisation. The treatment can produce a predictable ovulatory response to allow for timed intercourse or intrauterine insemination. 

Typically, doctors start prescribing this medication at a lower dose, such as 1 pill a day for five days. But, if your doctor finds that you’re not ovulating after continuous monitoring, then your dose can be increased. Treatment time usually doesn’t go higher than five days, but in rare cases it can be prescribed for up to 7 to 10 days. It’s important that couples have regular sexual intercourse every 2-3 days between the 9th to about 18th day of your menstrual cycle (depending on ovulation time). The most fertile period is about 5 days before ovulation to 1 day after.



Letrozole is a newer pill out in the market that has gained universal acceptance. It is classified as an aromatase inhibitor, which is a group of drugs that are designed to treat breast cancer. This also means that it is an oral chemotherapeutic medication, but don’t brush it off just yet because it’s not the kind of chemotherapy you may have in mind. While it prevents breast cancer recurrence, it also boosts fertility as its off-label use because of its hormonal effect. 

Like Clomid, Letrozole can also help a woman ovulate, especially for those who are obese and are struggling with Polycystic Ovarian Syndrome (PCOS); a condition that is also a deterrent to conception. Many find that this drug provides preferablee results than Clomid. A 2014 study showed that 27.5 percent of those on Letrozole eventually gave birth, compared to the 19.1per cent on Clomid. This means that more women ovulated with this treatment. Additionally, clomid is more likely to thin the womb lining (endometrium) negatively affecting implantation than letrozole. 

Read: 10 Common Causes of Infertility in Women 

A negative blood pregnancy test is required before you start a cycle. Depending on your situation, your OB may also prescribe a baseline ultrasound before you start therapy, to rule out the presence of ovarian cysts. Once everything checks out, you can start taking Letrozole on Cycle Day 2- 3 (Cycle Day 1 is the first day of menses) and continue for 5 days, just as you would with Clomid. 

Even though Clomid and Letrozole are constantly compared with each other, there’s really no telling from the get-go on which among the two is a suitable treatment for you. The treatment you’ll receive will rely on your fertility diagnosis, other medications you are taking, and pre-existing conditions. These drugs may jumpstart ovulation in patients, but it doesn’t guarantee that pregnancy will occur. 

However, beyond the Clomid and Letrozole face-off, there are other oral treatments that can also help with fertility issues. The list includes oral diabetic medications, dopamine agonists, and gonadotropin agonists.

  • Oral Diabetes Medicine (Metformin)

In some cases, an oral diabetes medication may also be prescribed, particularly for infertility in patients with PCOS. It is appropriate for women with no immediate desire for pregnancy but would like to cover their bases. In these instances, pre-treatment with oral diabetes medication will be considered.

Studies have shown that a 4 to 6-month pre-treatment prior to using Clomid can improve the rate of ovulation and live birth than when administered simultaneously. In addition, this drug can also decrease resistance to insulin, especially in women whose BMI is over 35, which can pose a problem with ovulation. Excess weight hampers the effects of Clomid, but this drug can facilitate weight loss in some women, especially with diet and exercise.

  • Dopamine agonists

Another hormone that is also linked to fertility issues is prolactin. It’s a hormone that is necessary for breast development and milk production, but having excess amounts in your system can interfere with ovulation and reduce your chances of conceiving. However, dopamine agonists can help reduce prolactin levels and eventually resume menstrual cycles. 

Injectable Medications 


Injectable medications are considered the next option to oral medications in the process of correcting infertility. These are considered when other oral drugs are not successful, or if several eggs are needed for infertility treatments like IVF. Typically, this treatment rakes in a higher percentage of women who will ovulate and more will get pregnant. 

Like Clomid, if you are aiming to induce ovulation, the doctor will usually start on a lower dose and increase only if necessary. The aim is to get 1-2 mature eggs ovulating and not more which will increase the risk of twin, triplets or even higher order multiple pregnancies. The exact dose is going to be determined by a number of factors such as:

  • your age
  • hormone testing results
  • and the response you had to any previous treatments

Since their potency is on a different level, the injections require closer monitoring with ultrasounds and on occasion blood tests in the doctor’s office every few days to track the development of the follicles. When the follicles have reached a certain size, another drug may be given to trigger the follicle to release its matured egg.

When it’s used to get multiple eggs in women in an IVF cycle, the prescribed dosage will be a lot higher than when it’s used to induce ovulation in a natural cycle as the aim in IVF would be to try to induce as many eggs that can be retrieved surgically. More eggs retrieved would hopefully translate to more good embryos that can then be subsequently selected and 1-2 implanted into the uterus at the appropriate time. 

Injected Hormones

If Clomid on its own doesn’t work, your doctor may recommend hormone injections to trigger ovulation. 

These include the following: 

  • Follicle-stimulating hormone (FSH)

It is used to treat infertility in women who are unable to ovulate. These drugs work directly on the ovaries to make multiple follicles. However, it is not effective in women with primary ovarian failure, or when the ovaries cannot produce an egg.

  • Human chorionic gonadotropin (hCG)

Also known as the “hormone of pregnancy”, it supports the normal development of an egg in the woman’s ovary. It is used to mimic the LH spike/ surge that naturally occurs for an egg to be released. This injectable triggers mature egg release from the follicle in the ovary and it must be administered at a precise time during the menstrual cycle. This is usually determined by ultrasound. It also helps prepare the endometrial lining for implantation. If administered in the context of an IVF cycle, the egg retrieval will usually be approximately 36 hours later. 

Additional medications during IVF: 

  • Gonadotropin-releasing hormone agonist (GnRH agonist) 

GnRH is normally produced by the pituitary gland to stimulate the ovaries to produce hormones. But, when it is taken as a medication, it initially increases hormone production which is then followed by a decline as the body senses that there is already too much that is being produced and so feedbacks to the brain to minimize FSH production. As normal hormone production is shut down by the ovaries, the process controls egg development during a fertility treatment cycle. This is called “down regulation” in a long protocol. After a period of time on GnRH agonist, injectable FSH is added to stimulate the ovaries in a controlled manner in the hopes that many eggs will all grow and mature at the same rate (synchronous) so that more can be retrieved later. 

  • Gonadotropin-releasing hormone antagonist (GnRH antagonist) 

This injectable is the opposite of an agonist and is occasionally used during IVF treatment in a short protocol as fertility doctors need to control the ovulatory cycle and prevent eggs from ovulating too early. It is usually given about 5-6 days after starting injectable FSH. Some follicles may grow faster than others hence this medication prevents the faster growing follicles from ovulating so that all can be retrieved at the same time. 

Hormone injections used to be quite daunting. In the past, they used to come in bigger needles, and a lot of mixing and reconstituting was involved. Fortunately, the injectable medications available today are pre-prepared, which means that they are in pure liquid form, so finer needles can be used. Hence, there is less mixing and a whole lot less anxiety is involved. You will be taught on how to inject yourself regularly or have someone do it for you. 

Role of Micronutrients in Fertility

Some promising studies have begun to shed light on the role of supplements in getting and staying pregnant. Since fertility is a complex equation and each person’s body is different, the science around it is still progressing. But there are proven benefits that several nutrients have on fertility and conception. It’s for this reason that supplements are part of the arsenal for improving fertility in both women and men. 

Supplements are divided into vitamins and minerals, anti-oxidants and adjuvants. Some of the supplements that aid fertility are listed below:

Vitamins and minerals: 

  • Folic acid 
  • Vitamin C
  • Vitamin D
  • Vitamin E
  • Zinc
  • Selenium

Anti oxidants:

  • Alpha lipoic acid
  • N acetyl cysteine 


  • Co enzyme Q 10 (maybe especially beneficial for patients above 35 yr)
  • melatonin 
  • DHA omega fatty acids 
  • L arginine (during implantation)
  • DHEA ( maybe beneficial for patients with low reserve)

While the list of medications and supplements available can be promising for those hoping to start a family, they are not always certain solutions and dosages have to be tailored for conception. 

We still have to consider your body’s response, pre-existing health issues, and other external factors. This is why we emphasise the importance of a thorough evaluation and a customised care plan that can direct us to appropriate medications and supplements that will be helpful to your case. 

If you’re struggling to conceive, and are not quite sure what’s wrong, you can take your concerns to certified OB-GYN. Just like pregnancy, tackling infertility is also a journey in itself where you will need the right companion. So take the first step into an expert-guided treatment. You may book a consultation with Dr Pamela Tan today

Infertility Diagnosis: 6 Tests to Check Why You’re Unable to Conceive

Getting pregnant may not always be a walk in the park for a lot of women, including many in Singapore where the total fertility rate continues to decline. Many women are facing roadblocks in trying to conceive and, unfortunately, they are unaware of the importance of fertility health checks. 

Singapore Fertility Rate

Source: Department of Statistics Singapore

An infertility diagnosis, albeit discouraging, is a reality to be reckoned with, especially if you plan on having a baby. Knowing what’s hampering you from getting pregnant will guide you and your doctor toward the right measures for correcting the problem. Since the biological clock waits for no one, it helps greatly when you act as sooner than later.

Before any treatment process can be initiated, the doctor must first arrive at a diagnosis, which we will be discussing in this post. 

What determines female fertility?

Perhaps one important aspect of female fertility is the egg factor. By the time you start menstruating, you will have half a million egg follicles left. 

An egg follicle is a sac that holds one egg. At the beginning of each menstrual cycle, the first few developing follicles are considered candidates for ovulation within that cycle. However, midway through the follicular phase, one follicle becomes dominant—a lot like a star athlete who stands out from the team. All resources go into “grooming” this single follicle while the others are left to die off. Imagine this happening every month, so by the time you hit 30, you lose 90% of your eggs. And by the fourth decade of life, you would’ve lost up to 97%. In time, these eggs will run out, eventually leading to menopause

Egg Follicle

Read: Managing Menopause: A Quick Guide On What To Expect When You’re Expecting

Going back to our “superstar follicle,” once it is ready, it releases the egg, which then travels out of the ovary and into the fallopian tube. After it is released, the egg has about 12-24 hours to be fertilised by sperm. If it doesn’t get fertilised in that short window, the egg begins to degrade. But if it gets fertilised, it travels to the uterus over the next 5-6 days to become a potential implant for pregnancy. 

Menstrual Cycle

What is infertility?

The World Health Organization (WHO) defines infertility as a “disease of the reproductive system” marked by a failure to achieve clinical pregnancy even after a year of trying. It is further classified into two: 

  • Primary infertility – wherein women have not conceived after at least a year of having sex even without the use of birth control methods
  • Secondary infertility – wherein women who have previously given birth are unable to get pregnant again or carry a baby to term 

Infertility diagnosis in women

There’s a variety of diagnostic tests done specifically on women to determine the cause for low fertility or outright infertility. One of the first things that are checked is the ovarian reserve. It sums up a woman’s chances of conceiving based on her current egg supply. Women with low ovarian reserves make fewer eggs. Hence, they have a lower chance of getting pregnant even with fertility treatment. A young woman with a lower than expected ovarian reserve (premature ovarian insufficiency) will menopause earlier than her peers. 

Aside from a diminishing number of eggs, the egg quality also tends to decline. However it is hard to check specifically for egg quality. A healthy egg has the ability to create a chromosomally normal embryo and hence fetus, which reduces miscarriage risk but is heavily dependant on the woman’s age. During an IVF procedure, the egg (and sperm) quality will determine the quality and number of surviving embryos but there isn’t a good predictor outside of the scope of IVF apart from general predictions based on age. At the age of 37 years old, the rate of chromosomal abnormality in the eggs is approximately 40%. The rate rises to 50% at 40 years old and almost 90% by 44 yrs. Hence the rate of decline in egg quality (and hence increase in miscarriage) is exponential. 

Decline in fertility rate

Ovarian reserve and quality can be tested in a variety of ways, mainly through imaging and blood tests. These tests can tell your OB or infertility specialists about your egg quality, egg reserves, and structural problems that may make conception challenging. Take a look at the different investigations below. 


1. Antral Follicle Count (AFC)

Antral (small) follicles measure 2-8 mm in diameter. They can be seen, measured, and counted by ultrasound as part of a fertility workup. To get an accurate assessment of the number of resting follicles, a transvaginal ultrasound (preferably between day 2 to 5 of the cycle) is performed. 

Interpreting the images obtained is fairly straightforward but it’s not possible to determine the total number of follicles since some are too small to be detected by ultrasound. Having just a few antral follicles developing in the ovaries indicates that the corresponding number of eggs are also low. 

Besides evaluating ovarian reserves, an AFC also gives an idea of where fertility stands in relation to age. It also identifies primary ovarian insufficiency (POI), and can help diagnose polycystic ovarian syndrome (PCOS). An ultrasound also screens for uterine polyps and fibroids or abnormal ovarian cysts that impact fertility.

Read: 10 Common Causes of Infertility in Women

2. Hysterosalpingogram (HSG)

Hysterosalpingogram (HSG)

HSG is an X-ray test that can check the size and shape of the uterine cavity, but it is done mainly to check whether the fallopian tubes are partially or fully blocked. 

A blockage is often caused by a scar tissue that may form inside the pelvis or around the fallopian tubes due to endometriosis, pelvic infection or previous abdominal or gynaecological surgery causing scarring. Any obstruction in the tubes inhibits the sperm from reaching the egg, which is one of the common reasons why women find it hard to get pregnant.

In HSG, a thin tube is threaded through the vagina and cervix. A contrast medium, or a dyed solution, is introduced into the uterus and fallopian tubes. When viewed on an X-ray screen, the dye shows up in contrast to the body structures as it outlines the inner size and shape of the uterus and fallopian tubes. Women with open tubes will have what’s called a free spill. The dye will spill from the ends of the fallopian tubes–showing that they are open or patent. Any blockage or stoppage of the dye, which can also be seen also through x-ray, indicates occlusion of one or both tubes. The HSG may also detect uterine polyps or scarred tissue within the cavity that can affect implantation.

3. Saline Hysterosonogram

Saline Hysterosonogram

Also called a sonohysterography, a saline hysterosonogram procedure may be ordered to evaluate the shape of the uterine cavity. The process is like a gynecologic exam involving the insertion of a transducer into the vagina after you’ve emptied your bladder. Through a small tube, which is also inserted into the vagina, a small amount of sterile saline is injected into the cavity of the uterus to study, so the doctor can study the lining using an ultrasound transducer. This procedure can determine if there are any polyps, fibroids, or other uterine abnormalities; and provides a clear picture of the soft tissues, which are clearly visible in x-ray images.

The alternative to evaluate the cavity is there is a suspicion of a uterine abnormality on regular vaginal ultrasound is to perform a short day surgical procedure called a hysteroscopy, dilation and curettage with polypectomy to remove a polyp or fibroid that is obstructing the cavity. It allows for an immediate therapeutic removal of the source of the problem while fully evaluating the cavity. 

Blood Tests

4. Follicle Stimulating Hormone (FSH) Screening 

FSH is produced by the brain to help regulate the menstrual cycle and egg production. FSH levels fluctuate throughout the cycle and as such, these are tested early in the cycle, usually around the second or third day. It can help the doctor gauge a woman’s ovarian function and evaluate the egg quantity. If results show elevated FSH levels, it means that a woman has lower ovarian reserve as the brain is trying to compensate for the poorer number of follicles by producing more FSH to stimulate their growth.

FSH screening may be used with other hormone tests for luteinizing hormone (LH), and/or progesterone levels are useful in:

  • determining the cause of infertility ( eg checking for successful ovulation)
  • diagnosing pituitary or hypothalamic disorders of the brain that can affect FSH production.

Often thyroid, prolactin levels and certain vitamins and minerals will also be tested to exclude hormonal imbalances and certain nutritional deficiencies that can affect fertility.

5. Anti-Mullerian Hormone (AMH) Testing

AMH is a protein made by the granulosa cells, which surround the follicle. Each follicle has thousands of granulosa cells completely engulfing and nourishing the egg. Having more eggs means more follicles, which consequently results in higher AMH levels. As you age, you will experience a natural decline in AMH levels, until it totally runs out when you hit menopause.

AMH  is considered a strong indicator of the ovarian reserve because the levels stay fairly consistent throughout the menstrual cycle, and can be tested on any day. AMH levels can also be a dependable guide in choosing the ideal fertility therapy. 

However, it is important to know that AMH does not predict pregnancy success but, rather, the ovaries responsiveness to an egg-freezing cycle or in-vitro fertilization (IVF) cycle. In general, women with higher AMH levels require less medication for stimulation and often generate a larger quantity of eggs ( and hence embryos).

Overall, the key intent in checking ovarian reserve is for fertility doctors to counsel women on the chances of success with fertility treatment. But know that screening doesn’t stop there. To pin down the root cause of infertility, your partner needs to undergo testing for you to get the full picture. 

Read: 6 Ways to Improve Your Chances of Getting Pregnant Fast

Infertility diagnosis in men 

Since one third of subfertilitiy is due to male factor and another one third due to combined male and female factors, it is important to check the male partner.

Semen analysis is an important test to check for sperm concentration, shape, movement, quality, infections, colour, or the presence of blood. This can also determine any infection in the reproductive system, such as Chlamydia, which can affect fertility. If semen analysis results are abnormal, a repeat test and additional blood tests may be ordered to identify the potential problem. 

If the results are poor, further blood tests can help point to the causes of male infertility because it can check the levels of testosterone and other hormones. Imaging can also check for any anatomical issues such as a blockage. For this, a scrotal ultrasound can be done to reveal issues such as varicocele, ejaculatory duct obstruction or retrograde ejaculation. 

So, if you have been trying to get pregnant for a year and remain unsuccessful, it’s time to take the next step and consider fertility testing. Know what’s holding you or your partner from conceiving. Get professional help and submit to necessary tests to find a suitable treatment for infertility.

If you have any questions, you may call +65 6254 2878 or drop us a line, here.

10 Common Causes of Infertility in Women

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!