The first thing to know is that women and men of all ages can experience infertility. Couples in their 20s can be just as infertile as couples in their early 40s. Age is only one aspect of fertility. Let's assume, however, that a woman's fertility is fine.
That the only thing to be concerned about is her age. Fertility peaks in most women in the 20s. A gradual but significant decline begins around age At around age 37, fertility starts to decline at a much more rapid pace.
Don't confuse this with your odds of getting pregnant overall. This is a per month statistic, not per year. Also, many studies struggle to distinguish whether pregnancy odds go down due to fertility or due to couples having less frequent sex. One study of couples looked at the odds of conceiving based on the day of sexual intercourse before ovulation. While we're discussing the effect of female age, it's important to mention that your partner's age matters as well.
Male fertility doesn't decline the same way female fertility declines, but male age does matter. Essentially, their odds halved. Keep in mind that these are the odds of conception. Just because you get pregnant doesn't mean you'll give birth. Miscarriage rates are higher for older mothers and fathers.
Age also increases the chances of genetic problems. Women are born with all the eggs they will ever have. The highest number of oocytes or eggs occurs when a baby girl is still in utero. At about 20 weeks gestation, a girl fetus has six to seven million eggs in her ovaries. At birth, she will be born with just over a million eggs. By puberty, between , to , are left. From this huge number of eggs, only will ever become mature and be released in the process known as ovulation.
Some people think menopause is the start of the fertility decline. This isn't so. Our bodies' reproductive capabilities slow down much earlier. As women age, the ovaries become less effective at producing mature, healthy eggs.
As you age and come closer to menopause, your ovaries will also respond less well to the hormones responsible for triggering ovulation. This includes fertility drugs and is why fertility treatment is less successful in women with low ovarian reserves.
What if you live a healthy lifestyle? What if you exercise, eat right , maintain a healthy weight , and avoid bad health habits? Even then, you will experience the natural fertility decline with age. With that said, bad health habits can have a negative effect on fertility.
For example, smoking has been found to speed up the natural fertility aging process in women. Maybe you're thinking you can just use fertility treatments. With IVF available, why worry about age? Unfortunately, it doesn't work that way. Just as your body doesn't respond as well to your own hormones the ones responsible for ovulation , your body will also not respond as well to fertility drug hormones.
You can get pregnant, go through a full-term pregnancy, and have a healthy child. However, conceiving is a complex process, especially for women over Your eggs are stored in a fluid-filled sphere called a follicle.
When you were born, you had about 1 million of these follicles that contained eggs. By puberty, that number was down to around , — only of which will actually go through ovulation released to get fertilized during your lifetime.
This means that even if you still have your menstrual cycle, as you get older, you will have cycles where an egg never gets released. In your 30s, your monthly chance drops to 20 percent. However, there are plenty of ways to increase the chances of fertilizing the eggs that you do have.
Together, you can come up with a plan to increase your chances of pregnancy. FACT : Every month during your menstrual cycle, your body releases an egg and waits for it to get fertilized.
Each month, your body decides which eggs to release — and it usually chooses the healthier ones first. This means that, over time, the eggs that you have left have a higher chance of having abnormal chromosomes, which can lead to birth defects, such as Down syndrome. There are also tests to find out your individual risk of having a baby with a chromosomal abnormality. These include screening tests, which assess the risk of having a baby with a birth defect, and diagnostic tests, which test the fetus for birth defects and genetic disorders.
Because the risk of chromosomal abnormality increases with the age of the mother, so does the risk of a miscarriage. Before 35, your chance of a miscarriage is 15 percent. Between 35 and 45, your chance goes up to percent. But remember — that means up to 80 percent of women conceive and carry to full term. They do, but no journal article I could locate contained these numbers, and none of the experts I contacted could tell me what data set they were based on.
Dunson, a biostatistics professor, thought the lower numbers might be averages across many cycles rather than the chances of getting pregnant during the first cycle of trying. More women will get pregnant during the first cycle than in each subsequent one because the most fertile will conceive quickly, and those left will have lower fertility on average. Most fertility problems are not the result of female age. Blocked tubes and endometriosis a condition in which the cells lining the uterus also grow outside it strike both younger and older women.
Fertility problems unrelated to female age may also explain why, in many studies, fertility at older ages is considerably higher among women who have been pregnant before. The rates of miscarriages and birth defects rise with age, and worries over both have been well ventilated in the popular press.
But how much do these risks actually rise? Many miscarriage statistics come from—you guessed it—women who undergo IVF or other fertility treatment, who may have a higher miscarriage risk regardless of age. Nonetheless, the National Vital Statistics Reports , which draw data from the general population, find that 15 percent of women ages 20 to 34, 27 percent of women 35 to 39, and 26 percent of women 40 to 44 report having had a miscarriage. These increases are hardly insignificant, and the true rate of miscarriages is higher, since many miscarriages occur extremely early in a pregnancy—before a missed period or pregnancy test.
What about birth defects? However, the probability of having a child with a chromosomal abnormality remains extremely low. Even at early fetal testing known as chorionic villus sampling , 99 percent of fetuses are chromosomally normal among year-old pregnant women, and 97 percent among year-olds. At 45, when most women can no longer get pregnant, 87 percent of fetuses are still normal. Many of those that are not will later be miscarried.
In the near future, fetal genetic testing will be done with a simple blood test, making it even easier than it is today for women to get early information about possible genetic issues. W hat does all this mean for a woman trying to decide when to have children? More specifically, how long can she safely wait? First, while the data on natural fertility among modern women are proliferating, they are still sparse. Collectively, the three modern studies by Dunson, Rothman, and Steiner included only about women 35 or older, and they might not be representative of all such women trying to conceive.
Second, statistics, of course, can tell us only about probabilities and averages—they offer no guarantees to any particular person. The data, imperfect as they are, suggest two conclusions. The bottom line for women, in my view, is: plan to have your last child by the time you turn There is no single best time to have a child.
Having children at a young age slightly lowers the risks of infertility and chromosomal abnormalities, and moderately lowers the risk of miscarriage. But it also carries costs for relationships and careers. Literally: an analysis by one economist found that, on average, every year a woman postpones having children leads to a 10 percent increase in career earnings.
Some women choose to freeze their eggs, having a fertility doctor extract eggs when they are still young say, early 30s and cryogenically preserve them. Because the eggs will be younger, success rates are theoretically higher.
Women who already have a partner can, alternatively, freeze embryos, a more common procedure that also uses IVF technology. At home, couples should recognize that having sex at the most fertile time of the cycle matters enormously, potentially making the difference between an easy conception in the bedroom and expensive fertility treatment in a clinic.
I wish I had known all this back in the spring of , when the media coverage of age and infertility was deafening.
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