Blog
Dr Christopher Ng
Consultant Obstetrician & Gynaecologist
MBBS (Imperial College, UK), MMed (O&G) (Singapore), FRANZCOG (Aust-NZ), FAMS (O&G) (Singapore)
As couples grow older together, both partners experience natural changes in their bodies that can affect their chances of conceiving. However, age does not affect male and female fertility in the same way, and these changes can have different implications for their ability to have children.
For couples planning to start or grow their family later in life, concerns may centre on how much time they have to conceive and whether they might face difficulties along the way. Understanding how fertility changes with age can help couples set realistic expectations, make informed decisions about family planning and recognise when fertility assessment may be appropriate.
Female fertility generally begins to decline in the early 30s, with a more noticeable reduction after 35 and a steeper decline towards 40. This is largely associated with age-related changes in the number and quality of eggs available for fertilisation.
As these changes progress, they can affect both the likelihood of conceiving naturally and the chances of a successful pregnancy.
Two important factors in age-related female fertility decline are the number of eggs remaining in the ovaries and their quality.
Although egg quantity and quality both decline with age, they are not interchangeable. A woman may have a relatively good ovarian reserve for her age, but this does not necessarily mean her eggs have the same reproductive potential as those of a younger woman.
As egg quantity and quality decrease, the likelihood of natural conception during each menstrual cycle also declines. This means that women in their late 30s or 40s may take longer to conceive than women in their 20s or early 30s, even when they have regular menstrual cycles.
Advancing maternal age is also associated with an increased risk of miscarriage, partly because chromosomal abnormalities become more common in eggs. These abnormalities can affect early embryo development and, in some cases, lead to pregnancy loss.
However, Fertility varies between individuals, and many women continue to conceive naturally in their late 30s and beyond.
Male fertility can also decline with age, although the changes generally occur more gradually than in women. Unlike female fertility, which has a natural endpoint at menopause, men can remain capable of fathering children much later in life.
However, advancing age can still affect sperm quality and reproductive potential, with possible implications for conception and pregnancy outcomes.
Advancing paternal age can affect several characteristics of sperm that contribute to successful fertilisation and embryo development.
These changes do not affect all men in the same way. Some maintain semen parameters within normal ranges well into later adulthood, while others experience fertility difficulties at younger ages, potentially due to hormonal or congenital factors.
Age-related changes in sperm quality can contribute to a longer time taken to conceive, particularly when other fertility factors are also present. However, the relationship between paternal age and conception is less pronounced than the relationship between maternal age and fertility.
Advancing paternal age has also been associated with an increased risk of miscarriage and certain genetic conditions in offspring. Some of these risks are linked to changes in sperm DNA that accumulate with age, although the absolute risk of many individual conditions remains low.
Unlike female fertility, male reproductive capacity does not have a clearly defined natural endpoint comparable to menopause. Many men remain capable of fathering children later in life, but age should still be considered when evaluating a couple's overall reproductive health.
As fertility changes with age, the timing of a fertility assessment becomes increasingly important, particularly for couples who have been trying to conceive without success. An assessment at a fertility clinic can help identify possible factors affecting conception and determine whether further evaluation or treatment should be considered.
Both partners should be included in the evaluation, as fertility difficulties can involve male factors, female factors or a combination of both.
The recommended timing of fertility assessment generally follows the woman's age, as female fertility tends to decline more significantly with advancing age.
These timelines serve as general guidance rather than strict requirements. Couples may benefit from earlier assessment if either partner has a known fertility concern, such as irregular menstrual cycles, endometriosis, previous reproductive conditions or suspected sperm abnormalities.
Fertility testing aims to identify possible reasons for difficulties conceiving and assess factors that could influence treatment planning. Depending on the couple's medical history and circumstances, the evaluation may include:
The results are interpreted alongside both partners' ages, medical histories and reproductive goals. While fertility tests can identify certain concerns, they cannot predict with certainty whether a couple will conceive naturally. Instead, they help guide decisions about further evaluation, continued attempts at natural conception or appropriate fertility treatment.
Age-related fertility changes are an important consideration when planning a family. Understanding these changes and seeking timely assessment can help both partners make informed decisions about when and how to pursue their plans for parenthood, and whether additional support may be needed.
GynaeMD Women's & Rejuvenation Clinic is a fertility clinic in Singapore that recognises the importance of helping couples navigate these decisions together. Care is led by Consultant Obstetrician & Gynaecologist Dr Christopher Ng, who draws on his experience in fertility assessment and treatment to provide guidance that considers both partners' circumstances, concerns and family planning goals.
If you and your partner are concerned about how age may affect your chances of conceiving, contact our clinic today to arrange a consultation with Dr Ng and discuss your next steps.
Healthy lifestyle habits can support fertility in both women and men. Maintaining a healthy weight, avoiding smoking, limiting alcohol consumption and managing existing medical conditions can help reduce factors that negatively affect reproductive health. However, these measures cannot reverse the natural decline in egg quantity and quality or fully prevent age-related changes in sperm.
Natural conception remains possible after 40, although the likelihood of pregnancy generally decreases with advancing maternal age. Individual fertility varies, and factors such as ovulation, reproductive health and the male partner's fertility also influence the chances of conceiving. Women over 40 who are planning a pregnancy are generally advised to consider fertility assessment earlier rather than waiting several months before seeking advice.
Yes. Age can influence the success of fertility treatments, particularly IVF using a woman's own eggs. As egg quantity and quality decline, fewer viable embryos may be available, and the likelihood of a successful pregnancy generally decreases. Male age and other fertility factors can also influence treatment outcomes. A fertility specialist can assess both partners' circumstances and discuss realistic expectations for the treatment options being considered.
Dr Christopher Ng
Consultant Obstetrician & Gynaecologist
Qualifications & Credentials
Dr Christopher Ng is a consultant obstetrician and gynaecologist with over three decades of experience in women's reproductive health. Having received medical education and training in Singapore, the UK and the US, his clinical experience includes fertility assessment and treatment, as well as laparoscopic surgery for gynaecological conditions that may affect fertility.
At GynaeMD Women's & Rejuvenation Clinic, Dr Ng provides personalised fertility care, including IVF and SO-IUI treatments. He takes a considered approach to helping individuals and couples understand their reproductive health, explore suitable treatment options and make informed decisions about their fertility journey.
