The menopause is a natural part of ageing and occurs when a woman stops having periods and is no longer able to have children. It’s a gradual process which happens over months or years.But when will it start? It’s a question many women wonder about, especially if you’re thinking about planning a family and your 20s are but a distant memory or maybe you’re just curious about what to expect and when.You might also be wondering how many more years of fertility you might have, and how much longer will it be before you start experiencing ‘the change’…Here's what does - and does not - influence the age at when a woman reaches menopause. THE TOP FACTOR There are a number of factors that affect women’s age at menopause, but one is more important than any other: the age their mother experienced menopause.Menopause is strongly genetically linked, so you’re very likely to fall within a few years either way of the age your mother was at menopause.With everything in life though, there are always exceptions to the rile and this isn’t always true, of course. Some women reach menopause at an unusually early age - before 45 or so - with no known cause. This is known as premature menopause and could be the result of an inherited issue or a one-time genetic mutation. So, if your mother reached menopause at 40, but her sisters and your grandmother were all around the average age of 50, it’s unclear whether you’ll follow your mother's path or theirs but if most of the women in your family, your mother included, reach menopause early, late, or somewhere in the middle, you can eye your calendar with some degree of confidence.The other exception to time is that some women who have had surgery such as a hysterectomy or certain other treatments, such as chemotherapy, will also experience menopause symptoms soon after their treatment ends, regardless of what age they are. MENOPAUSE AGE: THREE OTHER FACTORS Your mother's age at menopause is a key factor, but not the only one. Here are four others to consider: 1.Smoking No other lifestyle factor does more damage to your ovaries than smoking. So if you smoke and your mother didn’t, you’ll probably reach menopause earlier than she did. If she smoked and you don’t, you probably reach menopause later than she did. 2. Chemotherapy Most forms of chemotherapy used in younger women are at least mildly toxic to the ovaries. Many women go through temporary menopause while undergoing chemotherapy; if cycles do return (they don’t always), you can still expect to reach regular menopause a couple of years earlier than you otherwise would have. 3. Ovarian surgeryThe more you operate on the ovaries, the more healthy tissue gets damaged. So, if you’ve had diagnostic surgery for endometriosis, for example, you are likely to experience menopause symptoms a little earlier. WHAT WON'T IMPACT THE AGE I GET MENOPAUSE? Here are four things you might think would influence menopause age, but don’t: Age at first period Although the average age of the first period has been getting younger, there hasn’t been a corresponding shift in the average age at menopause. The average age the first period is now about 12.4 years old, down from 13.3 in women born prior to the 1920s, but the average age at menopause has been around 51.5 for decades. Pregnancy and Breastfeeding These have no impact on menopause age. Hormonal birth control methods Even if you’re using a birth control method that stops ovulation, it doesn’t stop the loss of follicles, the constant process of the ovary taking them from the resting pool of eggs. All the follicles available in the cohort that month die away, even if you’re not ovulating, so birth control doesn’t appear to delay menopause. Ethnicity A study of premenopausal and early perimenopausal women found that race/ethnicity played no role in what age the women experienced menopause. The Study of Women’s Health Across the Nation (SWAN) looked at cross section of women from different races from seven states and found that most of the women experienced menopause between the ages of 52 and 54.There is no way to delay menopause; it can only be sped up, not slowed down, by external factors.Some factors are still unknowns. For instance, some research links exposure to certain “endocrine-disrupting” chemicals to earlier age at menopause but it’s not certain that those chemicals cause earlier menopause, since the research only shows an association and doesn’t rule out other possible causes. Overall, the typical age when menopause starts hasn’t changed much over the years that these chemicals have been around. PREDICTING MENOPAUSE AGE Other than avoiding smoking, there’s probably not much you can do to influence the age at which you’ll reach menopause but as you get closer to that time, it will be easier to predict more accurately when it will happen.