The central issue revolves around the baby. It is well known that the older a woman is, the greater her chances are of having a child with a chromosome problem. The risk is small but so is the risk of detecting such a problem, performing an amniocentesis. As an example, a 35 year-old woman has a 1/200 chance of having a child with a genetic problem. The risk of losing the baby associated with an amniocentesis is also 1/200. Therefore, the risk and benefits are equal. Hence, we have created a magic barrier at 35 years of age.
The following table gives you an idea of the gradual increased risk of having a baby with a chromosome problem.
I prefer to accent the positive: I'll tell a 37-year-old prospective mom that she has a 129/130 chance of having a healthy child.
Our parenting advice is given as suggestions only. We recommend you also consult your healthcare provider, and urge you to contact them immediately if your question is urgent or about a medical condition.