Statistics, statistics.

We’ve all heard the metaphor of the ticking biological clock. While it implies that time can run out on an aging woman where she’ll be unable to bear children, there’s more to it. Not only does the ability to get pregnant decrease with time but the ability to bring the pregnancy to term (increasing odds of miscarriage and other complications) and the chance that there will be a chromosomal problem also increase.

Statistically, the point in which doctors really start to fret about the mother’s age seems to be at 35. In fact, on Amazon, I counted at least five books on “older” pregnancy that specifically mentioned “thirty five” in the title. Yet consider that older births are increasingly common. Births to 35-49 year-olds increased 72% from 1982 to 2000.

So we’re a couple of those people. Since we only were married around 30, we were already advanced, shall we say. Due to health issues we were forced to postpone pregnancy planning additionally and really only started trying a few years ago. After you reach a certain age, doctors weigh the potential complications brought on my early diagnostic tests vs. the value in diagnosing a serious genetic or chromosomal defect. The two main tests we hear about are CVS (Chorionic villus sampling) and amniocentesis. Since a CVS test can be given between the 9th and 14th week, it offers the earliest method of detecting significant problems that might cause the parents to consider terminating a pregnancy.

CVS can identify nearly all chromosomal abnormalities, including Down syndrome, trisomy 13, trisomy 18, and sex chromosome abnormalities (such as Turner syndrome and Klinefelter syndrome). The test is more than 99 percent accurate in diagnosing these conditions.

Obviously Down syndrome is the one that catches the eye. A 39 year-old woman has a 1-80 chance of conceiving a Down syndrome child. Although I’ve seen odds that put that a bit higher, those are the numbers we were quoted. The other statistic is that a CVS test has a 1-1600 chance of causing a miscarriage. This used to be much higher. Anyway, compare the two numbers and getting a CVS test is a no-brainer.

Still, it’s extremely scary and the last hurdle before we’re willing to start spreading the good news. One good thing? We’ll find out the sex of our baby (which is our choice to do)!