The months before baby's birth can be an exciting time, full of anticipation, planning and hope. Every woman wants to give birth to a healthy, happy baby. Most mothers are able to fulfill this dream, but every year, according to the March of Dimes, nearly eight million babies across the world are born with a serious birth defect.
We know that certain risks are unavoidable and unknown. Parents aren't often privy to knowledge of their genetic makeup, and unfortunately, risks are sometimes revealed only after an affected child is born. We also know that pregnancy after age 35 carries additional risk of conceiving a baby with a chromosomal defect such as Down syndrome. Perhaps due to the age of the egg, the likelihood that the contributed cell will contain an extra copy of chromosome 21 increases as a woman ages. Prior to age 30, the risk is less than 1 in 1,000, but the risk of giving birth to a baby with Down syndrome increases to 1 in 400 for women who conceive at age 35. By age 42, the odds increase to 1 in 60.
How to Better Define the Risks
Assessing the risks can begin before pregnancy with a preconception visit, when a midwife or physician can help a couple define some of the known risks of birth defects and refer them to a genetic counselor if necessary.
When conception does occur, it may be possible to take advantage of "integrated genetic screening" to further define the risks. Several screening tests can be combined to provide a more complete picture than one test alone could offer.