by Lauren Streicher, MD
Geena Davis was 48. Madonna was 44. Jane Seymour was 45. At first glance, one would think that these are the ages at which these celebrities won an Oscar, not the age at which they had a baby. The increasing prevalence of celebrity births after the age over 40 has resulted in a complacency about delaying pregnancy. What is not widely appreciated is that many of those pregnancies are a result of IVF using a donor egg from a younger woman. Certainly, some women do spontaneously conceive after the age of 40, but in general, fertility rates are low without some sort of intervention. It’s not that the rich and famous have a secret weapon to stop the clock, it’s just that they are more likely to have the means to buy young donor eggs .
While the number-one predictor of fertility is age, there is a significant variability in ovarian aging which make some women infertile at 35, and others still going strong at 40.
Genetics definitly plays a role. Even if you have nothing in common with your mother, her hormonal pattern is frequently predictive of when you are genetically destined to enter menopause . Fertility diminishes long before menopause, but women with a later menopause can usually conceive at a more advanced age than average. If your mom went through menopause late, you are likely to as well, which usually means you will be fertile longer.
The best test of fertility is to actually try and get pregnant. Short of that, here are indicators of your current fertility, and how long you will be fertile:
While regular menses are not a guarantee of ovulation or fertility, it is a pretty good indicator that your ovaries are pumping out estrogen, releasing an egg, and then producing progesterone. An over-the-counter ovulation kit will confirm ovulation. Obviously, if you are on the pill regular periods don’t count.
Blood Hormone Levels
Measuring your blood FSH (follicle stimulating hormone) level during your period is helpful. A low FSH level correlates with good ovarian function. A mid-range level means things may be winding down, and very high levels usually indicate the ovaries are out of business. The problem is, FSH levels do not steadily decline, they fluctuate from month to month, particularly as women get older. An FSH level tells you where you are hormonally on the day that you take the test. It does not predict how long you will stay at that level.
Anti-Mullerian Hormone (AMH)
AMH is the newest and probably best way to evaluate someone for ovarian reserve – essentially how good your eggs are, and how long they will be functional. AMH is secreted by cells from follicles in the ovary. Follicles are only present if healthy eggs are still around. AMH declines with age as the “good” egg pool declines and is completely gone after menopause. Unlike other hormones used to measure fertility, AMH doesn’t vary through the cycle and can even be measured in women who are taking birth control pils. While AMH is a a reliable way to know what ovarian reserve is there, there is not consensus as to what the lowest “okay” level is. In general, if AMH is above 0.5, there is good ovarian reserve.
What About Freezing Eggs?
If pregnancy is years away, the perfect solution would seem to be to simply store your eggs until you are ready to use them. Every day, I have patients that inquire about freezing eggs in order to increase the possibility of conceiving if life circumstances put pregnancy on hold.
While freezing embryos (an egg that has been fertilized with sperm and is at an early stage of development) is very successful, the technique of cryopreservation of unfertilized eggs is improving every day, but still considered to be experimental. But, if someone doesn’t have sperm in their life, there’s not a lot of choice.
While an increasing number of pregnancies are resulting from frozen eggs, success is not guaranteed since a thawed egg is not always a viable egg. In addtion, most women are also not thinking about freezing their eggs when they are in their twenties. By the time someone is considering it (in their late thirties), egg quality is already sub-optimal. Still, if you have the money, and don’t mind going through hormonal stimulation and egg retrieval, egg freezing is currently the best option to stop the clock.