Pregnancy Rates Falling?
It is true that pregnancy rates have been falling over the past twenty years in all races and ethnicities but NOT in all age groups! In women in their late 30s and early 40s, pregnancy rates actually went up. The National Center for Health Statistic released a report recently that showed that over the past 19 years, between 1990 and 2008, pregnancy rates for women aged 35-39 increased by 38% while those for women aged 40-44 increased by 65%. This was in contrast to pregnancy rates in teenagers aged 15-19 that decreased 40% between the years 1990-2008 and also to pregnancy rates in women in their early 20s that were 18% lower in 2008 than in 1990. It is thought that the overall decline in pregnancy rates and subsequent delivery rates is the result of birth control. In 2008 there were 68.1 live births per 1,000 women of childbearing age compared to 70.9 in 1990.
The USA’s birthrate is currently at its lowest point in 25 years due to not only birth control but also due to women who are postponing parenthood because of the poor economy. The fertility rate is not expected to rebound anytime soon according to a company that produces birth forecasts for consumer products. These marketers track the fertility trends because they affect the sales of products from diapers to minivans. The average number of births per women has decreased 12% from a peak of 2.12 in 2007 and this is expected to continue to fall. Apparently this decline in birthrate has only been seen in the less-educated and the Hispanic populations where the college-educated, non-Hispanic whites and Asian Americans have seen an increase in the birth rate.
As fertility physicians, we see many women who have delayed their childbearing and are now having difficulty conceiving. The biggest predictor of fertility is the age of the female and this is why it is important for women to try their best not to postpone their fertility or at least be informed regarding the sequelae if that is what a woman chooses to do. Women have the most eggs they are ever going to have when they are in their moms’ uterus and this number declines exponentially until the age of menopause when they virtually have no functional eggs remaining. Why this decline if women only ovulate 400-500 times in their lifetime you may ask? Well each month women have a group of eggs that are there for the picking. Only one is chosen to ovulate and the rest die off leaving females with a number of around 25,000-35,000 when they hit the age of 37-38. And, these are eggs that have also been around for that long and therefore do not divide as well as they would have when females were in their twenties leading to declining pregnancy rates and increasing miscarriage rates. So, regardless of birth control and the economy, it is important for women to remember that there are limits to their fertility and that if nothing else, they should become educated as early as possible so they can make truly informed decisions about their future family building options!
Kari Sproul von Goeben, M.D.