For many women, 35 has long been viewed as the age when fertility begins to decline sharply. However, fertility specialists say this common belief oversimplifies a much more gradual biological process.
While pregnancies after 35 are often classified as advanced maternal age, experts emphasise that there is no sudden “fertility cliff” on a woman’s 35th birthday. Instead, fertility declines steadily over time, with factors such as overall health, genetics, lifestyle and a partner’s fertility also influencing the chances of conception.
Research by Emily Mann, a sociologist at the University of South Carolina, suggests that the significance attached to age 35 has become deeply rooted in public perception, even though fertility changes occur progressively rather than abruptly.
Recent data from the US Centers for Disease Control and Prevention (CDC) reflects changing family planning trends. Although the overall fertility rate declined in 2024, birth rates among women aged 35 to 39 remained stable, while births among women aged 40 and above increased by 2%.
Experts say many women are choosing to have children later in life due to higher education, career goals, financial stability and waiting for the right partner. Advances in fertility treatments, including in vitro fertilisation (IVF), have also made pregnancies later in life more common.
Doctors stress, however, that age remains the most significant factor affecting fertility. The chance of conceiving naturally decreases gradually because both the number and quality of eggs decline over time. Women are born with all the eggs they will ever have, and this reserve steadily diminishes with age. As women grow older, the likelihood of chromosomal abnormalities and miscarriage also increases.
The age of 35 became an important medical benchmark decades ago because it marked the point at which the risk of miscarriage from amniocentesis, an invasive prenatal test, was roughly equal to the risk of detecting chromosomal abnormalities in the fetus. Although medical practice has evolved, the age threshold has remained widely recognised.
Healthy couples in their 20s and early 30s generally have a 25% to 30% chance of conceiving during each menstrual cycle. By age 40, that chance falls to below 10% per cycle, reflecting the natural decline in fertility.
Experts also note that fertility changes are not limited to women. Men continue producing sperm throughout life, but sperm quality and testosterone levels gradually decline with age, particularly after the 40s. Chronic health conditions and lifestyle factors may also affect male fertility.
Current medical guidelines recommend that women under 35 seek fertility evaluation after one year of trying to conceive without success, while women over 35 are advised to consult a specialist after six months.
Specialists say the key message is that fertility is influenced by many factors and declines gradually with age—not suddenly when a woman turns 35.
