How much do you really know about your fertility? If you’re like most people, it’s far less than you think. With more women choosing to have children later in life than ever before, fertility issues have become much more prevalent in today’s world. Many couples are waiting longer to conceive for a variety of reasons including job and financial security, education, military service, having met each other later in life, or simply choosing to wait longer in their relationship before starting a family. Whether you’re trying to get pregnant soon or planning to wait a decade, here are the top five fertility facts you should know.

1. Your fertility is mostly determined by genetics.

Genetics influence how many eggs you are born with. At birth, women have about two million eggs in their ovaries. For every egg ovulated during your reproductive life, about 1,000 eggs undergo programmed cell death, so a woman’s supply of eggs is continually reducing over time. Additionally, some women undergo premature menopause which can be a hereditary issue. If your mother underwent premature menopause, you may want to consider starting a family earlier in your life than you might otherwise. Genetics are equally important for sperm production and fertility in men. It is estimated that half of infertility in men and women is genetic.

2. Infertility can affect both men and women.

Women aren’t the only ones who experience infertility – men have fertility issues as well. A male factor is the cause of 30-40% of infertility and may be due to to low sperm counts, poor sperm quality, or both. Male infertility can also be the direct result of genetics, weight issues, alcohol consumption, taking certain medications, or smoking.

3. By age 44, most women are infertile.

For healthy women, fertility peaks in their mid 20s, begins declining at age 27, then nosedives around age 37. By the time a woman is 40, her fertility is a quarter of that when she was 20. Women are born with all of the eggs that they will ever produce, so once these eggs begin to age, there is no way to halt or reverse this process. Other complications, such as miscarriage, also arise as a woman ages.

4. Your weight affects your ability to conceive.

Obesity is a leading cause of infertility for both men and women and has been shown to both decrease sperm quality and disrupt menstrual cycles. Having a body mass index (BMI) less than 18 or over 32 is associated with problems ovulating and conceiving. If you or your partner is obese, even a 10% decrease in your weight could have a demonstrable impact on your fertility. A healthy diet consisting of protein, complex carbohydrates, and healthy fats can improve your weight and overall well-being.

5. Poor lifestyle factors can lead to infertility.

Small changes to your lifestyle can potentially make a huge difference in your fertility — this goes for both men and women. Lifestyle factors that can affect your fertility include smoking cigarettes (infertility rates among smokers are about twice as high as among nonsmokers), exposure to secondhand cigarette smoke, chronic stress, drinking alcohol, eating a poor diet, and not getting enough exercise.

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