One of the most important factors impacting a woman's ability to conceive a child is her age. Women in their twenties and early thirties are the most likely to conceive. Unlike men, who continue to produce sperm throughout their lives, a woman is born with all the egg-containing follicles in her ovaries that she will ever have. The number of these follicles, and hence the eggs, decrease with age and are exhausted by 5 to 10 years before menopause. The follicle count of one million at birth drops to about 300,000 at puberty. Of these follicles, only about 300 will be ovulated during the reproductive years. The majority of the remaining follicles undergo an ongoing gradual process of loss called follicular atresia. Atresia is a degenerative process that occurs regardless of pregnancy, normal menstrual cycles, use of birth control, or infertility treatment.
What is Advanced Maternal Age (AMA)
The past several decades have seen rapid changes in society and an increase in the number of women delaying their first pregnancy and childbirth until their late thirties and early to mid-forties. A number of socioeconomic trends including cultural expectations and financial situations have influence such a tendency. Several medical studies concluded that women of an “advanced maternal age” (AMA) generally defined as age 35 years or more at the time of delivery, needed additional medical attention, due to an increased genetic and obstetric risk that occurred in such pregnancies. Complications like hypertension, gestational diabetes, low lying placenta, operative delivery and dysfunctional labor are more common in AMA pregnancies.
How Age Impacts Female Fertility
Fertility declines as a woman ages due to the normal age-related decrease in the number and quality of eggs that remain in her ovaries. This decline becomes more dramatic after the age of 35, and occurs in spite of the fact that women generally maintain regular, ovulatory menstrual cycles well into their fifties. Even though women today are taking better care of themselves than ever before, improved health in later life does not offset the natural age-related decline in fertility. The chances of pregnancy in a healthy woman decrease from 20% per cycle at age 30 to 5% per cycle at age 40. That means fewer than 5 out of every 100 women at age 40 are expected to be successful each month.
Fibroids, endometriosis, and tubal disease are also more common in older women and can affect fertility. There is also some evidence of a decrease in the capacity of the aging uterus to carry a pregnancy to term.
Egg Quality and Age
Starting in mid-to-late-30s, a woman's chances of miscarriage increases because egg quality decreases. With age, the frequency of genetic abnormalities in an egg increases. These abnormalities are related to an egg having either too few or too many chromosomes (aneuploid). Embryos that do not have exactly 46 chromosomes (23 from the egg and 23 from the sperm) are more likely to not result in pregnancy or have a higher rate of miscarriage. Research has indicated that the occurrence of loss was more than one fifth of all pregnancies for 35 year old women and this number rose to 54.5% at 42 years
Are all Infertility Conditions Age-Related?
Not all infertility conditions age-related. Indications of medical problems unrelated to age and affecting a couple’s ability to conceive, include absence of periods or irregular periods, sexual dysfunction, a history of pelvic disease, or prior ovarian or other pelvic surgery. Also other risk factors, when one may consider seeking earlier advice include a history of early menopause (before age 51) in the family (mother or sister), cigarette smoking in either partner, exposure to chemotherapy or radiation to treat cancer in either partner, and a prolonged exposure to toxic chemicals (certain pesticides or solvents).
Fertility Testing for Women Over 35
Ovarian reserve testing can be used to assess the quantity and quality of remaining eggs. There is no single test that measures ovarian reserve perfectly. The ovarian reserve tests only estimate the number and quality of the remaining eggs using blood tests for follicle-stimulating hormone (FSH) or anti-mullerian hormone (AMH) levels. An ultrasound is sometimes used to count the number of follicles (antral follicle count).
Is it Possible to Reverse Reproductive Aging?
No. It is not possible to reverse the natural aging process of the egg or sperm. Unlike men, a woman is born with all her eggs which mature and are gradually depleted in number as she ages. So there are no methods or treatments to grow more or new eggs or preserve the quality of those eggs that remain. Adopting a healthy lifestyle that reduces stress can improve the overall health of a woman. However, treatment of age-related infertility is somewhat limited, with no specific treatment available for egg abnormalities or decreased ovarian reserve.
Is There a Medical Approach to Improve Fertility in Those Over 35?
In general, treatment for normal older women is directed toward increasing the number of available eggs through in vitro fertilization (IVF) with controlled ovarian hyperstimulation using hormonal medication. Egg donation, which replaces the defective egg with that of a younger woman appears to largely, if not completely, reverse the age-related decline in female fertility.
When to Seek Help for Infertility Based on Age
General awareness regarding the effect of age on fertility is essential. Routinely, infertility examination is deferred until after at least one year of unprotected intercourse. If the female partner is older than 35, a couple should seek evaluation if they have not been able to conceive after six months, due to the rapid decline of treatment success over time. In those who are older than 40, immediate medical assessment is recommended.
The rate at which fertility decreases varies widly in women. Understanding all of the options available and and being aware of your own needs and goals will allow you and your partner to make the best decisions for you.