Women lose 90 per cent of the eggs in their ovaries before the age of 30, new research has shown. The mathematical model shows that the average woman has only 12 per cent of her eggs left by the age of 30 and only three per cent by the age of 40.
Females have already lost about 90 percent of their eggs by the time they hit 30, according to a new study by the University of St. Andrews and Edinburgh University in Scotland. "Women lose eggs a lot faster than we thought," Dr. Marie Savard, a "Good Morning America" medical contributor, said on the ABC News show.
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.
How many eggs do women have in their 30s? There is no one right answer to this question, as certain factors – such as smoking or other personal factors – may mean a woman has fewer eggs than others. The average number of oocytes at the age of 30 would be around 72,000 (12% of maximum pre-birth levels).
By puberty, a woman's egg count might be 1 million; at 25, maybe 300,000. Then, around 35, the decline starts to get a bit steeper until all eggs have been depleted (menopause).
Even though women start with 1–2 million eggs, by the time you reach puberty only about 300,000–400,000 of the eggs you were born with remain. The monthly cycle described above then continues throughout a woman's life until there are no eggs left.
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.
The AMH Test
The level of AMH in a woman's blood helps doctors estimate the number of follicles in her ovaries; the more follicles a woman has, the more eggs she can release, and the better her chances of pregnancy.
The ideal childbearing age is often considered to be in the late 20s and early 30s. Pregnancies later in life could come with some health risks. However, age is just one factor when it comes to giving birth to a child.
A woman is born with all her eggs. Once she starts her periods, 1 egg develops and is released during each menstrual cycle.
Peak male fertility is around 25-29 years old. Sperm quality begins to decline at 30. At 45, men begin to experience a significant decrease in semen volume. Older men can also take longer to conceive a child.
While 30s is a good time to conceive, there might be many chances of chromosomal abnormalities or other abnormalities in the egg due to an increase in age. These abnormalities can lead to failure in implantation, miscarriage, or an unhealthy baby.
For example, a woman at 30 often has around 100,000-150,000 eggs in reserve. By 35, that number is likely around 80,000. Late into the thirties, that number could be 25,000, 10,000, or fewer.
Egg quality and quantity also decline in a woman's 30s and 40s. While the total number of eggs cannot be increased, research has shown that egg quality can be improved. Supplements containing Myo-inositol, folic acid and melatonin have been shown to help improve egg quality and ovarian function.
Anti-mullerian hormone (AMH) test
If your AMH level is 1.5 ng/ml or higher, your egg supply is normal. But if it dips below that level, you have a lower-than-normal egg quantity.
After age 35, there's a higher risk of pregnancy-related complications that might lead to a C-section delivery. The risk of chromosomal conditions is higher. Babies born to older mothers have a higher risk of certain chromosomal conditions, such as Down syndrome. The risk of pregnancy loss is higher.
By 30, a woman's fertility starts to decline, and after 35 the rate accelerates. Specifically, before 30, women have an 85 percent chance of conceiving within a year; at 30, those odds drop to 75 percent; and at 35 the chance drops to 66 percent, research has found.
While it may take a bit longer to get pregnant if you're 35 or older, the average time it takes to conceive is still high. Women under 25 have a 25 percent chance of conceiving per cycle, compared to 15 percent among women between the ages of 35 to 39 (the rate drops to 5 percent by the age of 40).
By 40, less than half of a woman's eggs are considered normal. Egg quality is largely determined by the ovarian environment that the eggs spend their final 90 days of development in; women in their 40s generally have a poor ovarian environment for producing high-quality eggs.
The remaining eggs/follicles will wither and die. Pre-pubertal girls do not produce the gonadal hormones that are necessary for the second phase of development, so the many eggs that started to mature will simply wither away.
However, the belief that the follicles are empty is under debate. The incidence of this syndrome has been estimated at 0.6–7.0%.