You’ve heard of a biological clock, right? It’s not just an antiquated turn of phrase to talk about a woman’s advancing childbearing years. It actually refers to a real situation women face when they wait to get pregnant: The dwindling number of eggs they’ll have as they age. Here, our experts weigh in on other real risks you might face if you wait to get pregnant.

1. You’ll lose eggs. As we mentioned above, women are born with a finite number of eggs. In each menstrual cycle, we lose some. And with fewer eggs, fertility decreases. “Fertility typically declines with advancing age and often times we may begin to see the first signs of diminished fertility at about age 32, definitively by 35, and most definitely after age 40,” says Alyssa Dweck, M.D., a gynecologist in New York and assistant clinical professor at the Mount Sinai School of Medicine. That’s why if you’ve been unable to conceive by age 35, it’s time to talk to your gynecologist to see if he or she can help optimize your chances, says Mary Jane Minkin, M.D., a clinical professor of obstetrics and gynecology at Yale Medical School.

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2. You could have an increased risk of miscarriage or abnormal genetics. The eggs that do hang on as you age are susceptible to genetic alteration, Dweck says, and that can lead to an increased risk of miscarriages. (The majority of miscarried fetuses are genetically abnormal.) Otherwise, genetic alteration can cause other problems, increasing the incidence of Down’s Syndrome, along with other disorders. “The good news is we can test for these things,” says Minkin, “but women then need to make a decision about terminating a pregnancy.”

3. You have an increased risk of medical problems yourself. More bad news: the incidence of medical complications are also higher in older moms, including an increased risk of hypertension, diabetes and premature delivery, Dweck says. There are things that you can do to combat at least some of these issues. “If you get down as close to your ideal body weight as possible, and exercise often — ideally every day — to keep your blood pressure in control, you will do well,” says Minkin.

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If you want children and anticipate having them at an older age, the best thing you can do is get the conversation started with your gynecologist as soon as possible. Minkin suggests broaching the subject at about 32, “in an effort to give the biggest cushion of time for women who may want to delay childbearing and wanted to know their options.”

Those options might include cryopreservation or egg freezing, Dweck says. “In addition IVF is now incredibly successful, with most kinks worked out and definitely more affordable than in years past,” she adds. “In fact, IVF is often the a first step in helping the older woman to get pregnant at will despite age.”