The main explanation for this, is that women are born with a finite number of eggs, and from that moment onwards, the number of eggs is declining all the time, until women go through their menopause at around 50-51. Nonetheless, women in their 40s do still ovulate each month.
It's possible, but almost half of women over 40 experience fertility issues, according to the CDC. Women over 40 have about a 5 percent chance of getting pregnant in any single ovulation cycle. (That's compared to a 25 percent chance for women in their 20s and early 30s.)
Age is a big factor impacting a woman's ability to conceive. Women between the ages of 40 and 44 have a 30% chance of infertility, compared to a 7.3% to 9.1% chance for women up to age 34.
Because women in their late 30s and 40s have a higher percentage of abnormal eggs, it's much more likely that their one egg each month will be abnormal. That's why natural fertility declines with age, and why we see infertility, miscarriage, and genetic disorders more often with women over 35.
“A woman's ovarian reserve in her 40s is just not as hearty as it is when she is in her 20s or 30s,” explains Daren Watts, MD, an OBGYN at St. Mark's Hospital in Salt Lake City, Utah. “This is the number one issue for women trying to get pregnant after age 40.”
A woman's peak reproductive years are between the late teens and late 20s. By age 30, fertility (the ability to get pregnant) starts to decline. This decline happens faster once you reach your mid-30s. By 45, fertility has declined so much that getting pregnant naturally is unlikely.
Once your discharge becomes scant and sticky again, ovulation is over. Some women also report mild breast tenderness around this fertile window time. Pay attention to your body each month and start to track noticeable changes and symptoms.
How many eggs does a woman have at 40? By the time a woman reaches 40, she'll be down to about 18,000 (3% of her pre-birth egg supply). Although the chances of conception are lower, this does not mean it is impossible to conceive at this age.
At age 30 about 30% of eggs are chromosomally abnormal. By age 40 about 60% are abnormal and by 44 years old 90% are abnormal.
Pregnancy in Your 40s
If you get pregnant after 35 years old, experts call this an “advanced maternal age” pregnancy. But it's still possible to get pregnant and deliver a healthy baby in your 40s. Childbirth at older ages has become more common too. Since the 1990s, birth rates in people aged 40-44 have gone up.
There is no absolute cut-off age to have a child with your own eggs, but fertility treatments, such as IVF after 42, become increasingly complex. Life doesn't always go as planned. You may have wanted to have kids earlier, but pursuing a career or not finding the right partner may have put those plans on hold.
Although it is possible to become pregnant at 43 through sexual intercourse, the chance for conception drops steeply at this age until a woman clinically enters menopause.
Miscarriage issues
To wit, between the ages of 40-44, 34% of pregnancies end in miscarriage. After 45, this number jumps to 53%. These numbers shouldn't discourage you, however, especially if you read them in reverse: 66% of pregnancies between the ages of 40 and 44 don't end up with a miscarriage.
It is true that fertility does decline with age, but many women conceive naturally aged over 40 and go on to have healthy pregnancies and healthy babies.
Women under the age of 35 are the most likely to benefit from a six-cycle regimen. Women 40-42 (using their own eggs) had a 31.5% live birth rate at the six-cycle mark. Women older than 42 (using their own eggs) had a <4% live birth rate at the six-cycle mark.
The study published by the University of St. Andrews and Edinburgh University in Scotland found that women have lost 90 percent of their eggs by the time they are 30 years old, and only have about 3 percent remaining by the time they are 40.
Irregular period cycle and difficulty conceiving
If you are facing issues conceiving and have not been able to conceive for a while now, it could be one of the signs of bad egg quality.
However, pregnancy success rates using your own eggs drops considerably for women over 40. In the U.S., the likelihood of achieving a live birth from one egg retrieval in women between ages 41-42 is less than 20% (http://sart.org); in women above age 42, the rate is less than 5%.
There are two good ways to measure egg count: an antral follicle count and an AMH (anti-Müllerian hormone) test. During an antral follicle count, a doctor uses ultrasound to count the visible follicles. Each follicle contains an immature egg that could potentially mature and ovulate.
Egg Count in the 40s
From this point on, it's on the decline with a female losing roughly 1,000 eggs per month. After 40 or so years of this monthly detrition, the amount of eggs left in a woman's ovarian reserve is considerably low and will keep on diminishing until menopause between ages 45-55.
How many days after ovulation is it possible to get pregnant? Pregnancy is possible 12–24 hours after ovulation. This is because the released egg can only survive 24 hours before the sperm can no longer fertilize it.