Understanding female fertility
Female fertility is influenced by several factors, including age, ovulation, ovarian reserve, the fallopian tubes, the uterus and certain medical conditions.
Understanding these different parts can help make sense of why pregnancy may be taking longer than expected and what information a fertility assessment may provide.
What needs to happen?
For pregnancy to occur naturally, several parts of the reproductive system need to work together. A difficulty at one stage may affect the chance of conception, although having a particular condition does not necessarily mean pregnancy cannot occur.
Ovulation
An egg needs to mature and be released from an ovary. Irregular or absent ovulation can make conception more difficult.
Egg and sperm
Sperm needs to reach the egg at the right time for fertilisation to occur. This is why fertility assessment may involve both partners.
Fallopian tubes
The fallopian tubes provide the pathway where egg and sperm can meet and through which a fertilised egg travels towards the uterus.
Uterus
The resulting embryo needs to reach the uterus, where implantation may take place in the endometrium, the lining of the uterus.
Why does age matter?
Female fertility changes with age because both the number of remaining eggs and their reproductive potential change over time. Age is therefore one of the most important factors considered when discussing fertility.
The decline is gradual at first and becomes more significant as reproductive age increases, particularly from the mid-30s onwards. This does not mean that everyone of the same age has the same fertility, but age provides important context when interpreting other test results.
Fertility treatment may help overcome some barriers to conception, but it cannot completely reverse the biological changes associated with egg ageing.
Age provides important information about reproductive potential, while anti-Müllerian hormone (AMH) is mainly used as a marker of ovarian reserve. One should not be used as a substitute for the other.
Periods can tell us part of the story
Regular menstrual cycles often suggest that ovulation is occurring, while very irregular or absent periods may indicate that ovulation is less predictable or not occurring regularly.
PMOS, previously called PCOS
Polyendocrine metabolic ovarian syndrome (PMOS) is the new name for the condition previously known as polycystic ovary syndrome (PCOS). The name is changing to better reflect that it is a broader hormonal and metabolic condition, rather than simply a condition involving ovarian “cysts”.
PMOS can affect ovulation and menstrual regularity, although its features and impact vary from person to person.
Other hormonal factors
Other hormonal or endocrine factors can also affect menstrual cycles and ovulation. Depending on your history and symptoms, your doctor may consider tests such as thyroid-stimulating hormone (TSH) and other relevant hormone tests.
What do AMH and antral follicle count tell us?
Ovarian reserve refers mainly to the number of eggs remaining in the ovaries. Two commonly used markers are anti-Müllerian hormone (AMH), measured through a blood test, and antral follicle count (AFC), assessed by ultrasound.
What they can help with
AMH and AFC can provide useful information about ovarian reserve and can help doctors anticipate how the ovaries may respond if ovarian stimulation is needed as part of fertility treatment.
What they cannot tell you
AMH is not an egg-quality test and it cannot, on its own, tell you whether you will become pregnant naturally. Results need to be interpreted alongside age, medical history and other findings.
For natural conception, the fallopian tubes need to allow sperm and egg to meet and provide a pathway towards the uterus. Previous pelvic infection, surgery or other conditions may sometimes affect the tubes.
If tubal patency needs to be assessed, your doctor may recommend a specific test such as a hysterosalpingogram (HSG) or another appropriate form of tubal assessment.
An ultrasound can provide information about the uterus, ovaries and endometrium. Findings such as fibroids, polyps or adenomyosis may sometimes be relevant to fertility, depending on their size, location and individual circumstances.
Importantly, finding one of these conditions does not automatically mean it is the reason pregnancy has not occurred. Your doctor can help determine whether a finding is likely to be clinically relevant and whether further investigation is appropriate.
Endometriosis is a condition in which tissue similar to the lining of the uterus grows outside the uterus. It may affect fertility in different ways, including through inflammation, ovarian endometriomas or changes around the reproductive organs.
Ultrasound can identify some forms of endometriosis or findings associated with it, particularly ovarian endometriomas, but a normal ultrasound does not necessarily rule out endometriosis.
If your symptoms or history suggest endometriosis, your doctor can discuss whether further assessment is appropriate.
General health can form part of the fertility picture. Smoking, alcohol intake, nutrition, physical activity and weight may be relevant depending on individual circumstances.
A healthy lifestyle can support overall and reproductive health, but it is important not to imply that fertility difficulties can always be “fixed” through lifestyle changes. Healthy habits also cannot reverse the age-related changes that occur in eggs over time.
When should I consider a fertility assessment?
Under 35
If pregnancy has not occurred after around 12 months of regular unprotected intercourse, it may be worth speaking to a fertility doctor.
35 and over
It may be appropriate to seek advice after around 6 months. If you are over 40, earlier assessment may be appropriate.
You may also want to seek advice sooner at any age if you have very irregular or absent periods, known or suspected endometriosis, a history that may affect the fallopian tubes or ovaries, or another known fertility factor.
A fertility assessment is about getting information
Having a fertility assessment does not mean you are committing to IVF. It can help build a clearer picture of your current circumstances and give you an opportunity to discuss what, if anything, may be appropriate next.
At IVF(SG), an assessment may include:
- Hormonal profile, including TSH and AMH
- Pelvic ultrasound
- Semen analysis for your partner
- Sperm DNA fragmentation where included in the selected assessment
- Consultation with Dr Yeong to review the results
Female fertility FAQs
Does a low AMH mean I cannot get pregnant naturally?
No. AMH mainly provides information about ovarian reserve and is not, by itself, a test of whether natural pregnancy can occur. It should be interpreted together with age, medical history and other fertility factors.
Does a normal AMH mean my fertility is normal?
Not necessarily. AMH is only one part of the fertility picture. It does not directly assess egg quality, whether the fallopian tubes are open, the uterus, ovulation or sperm factors.
Can I have regular periods and still have fertility difficulties?
Yes. Regular cycles can suggest that ovulation is occurring, but other factors such as age, the fallopian tubes, uterine factors, endometriosis or sperm may still be relevant.
Can an ultrasound tell if my fallopian tubes are blocked?
A standard pelvic ultrasound does not usually confirm whether the tubes are open. If tubal assessment is needed, a specific test such as an HSG or another appropriate test may be recommended.
Does coming for a fertility assessment mean I need IVF?
No. An assessment is intended to provide information. Depending on your results and circumstances, the next step may be further investigation, trying for longer, another form of support or discussing treatment where appropriate.
