Genetic testing

The older a woman is, the higher the likelihood that her baby will have genetic defects. The most common of these is Down Syndrome and women over 35 are considered most at risk. K is 37, so we were looking at numbers that said 1 in every 230 babies born to a 37-year-old woman has DS. However, the chances of a fetus having it are even higher, because many fetuses with the defect are terminated. Add to that the fact that K will be 38 when the baby is born and we were looking at something like 1 in 120.

These figures caused me great stress. I spent hours and hours number crunching. I found out about the screening test we were due to have and factored in false positives, false negatives and came up with an elaborate table about what it would mean should our screening test come back positive. It became clear that however high the odds were that the baby would have DS, they were massively higher that the screen would come back positive. So not only did I fear DS itself (1 in 120), I had to accept that 9 out of every 10 positive screens were false. Turns out that there was a 1 in 20 chance we'd be faced with a getting news at the screen that wouldn't allow us to breathe easy, and would require a diagnostic test called CVS. Even though the likelihood would be that the diagnostic test would come back with a good result, the stress of going through that would be terrible. No-one talks about this aspect of pregnancy, and we vowed that we'd be open and honest with people about the toll it takes.

With all this racing through our heads, we showed up at the hospital on March 2nd for the genetic screen. First we had an interview with a genetic counselor who asked us about family histories, and told us what our options were for screening. We opted for a sequential screen which discloses the results of the first screen and doesn't roll them into the second screen at 16 weeks for one final number. I wanted to know NOW and K agreed. If this screen looked good, we could go ahead with our plan to tell people in the 13th week.

Now it was the moment of truth. We went into the ultrasound room. The technician was going to measure something on the back of the baby's neck called the "nuchal translucency". This layer of fluid is present early in a pregnancy, and is a pretty good indicator of risk for DS. A typical measurement of the NT is up to 2.5mm. Anything beyond that indicates an above average chance of DS. The bigger the NT gap, the higher the chances of DS, to the point where a 6mm gap is something like a 1 in 4 chance.

The image came up on the screen. I could barely look. As amazing as it was to see this little creature, I wanted the tech to get the measurement so I could either relax or panic. After spending a few moments to get the little thing to orient itself properly she took the reading. When she said "1.2mm" I was ecstatic! It was definitely one of the top five single moments of my life, whilst the lead-up to both this and the awful appointment at 7 weeks were in the top five worst times.

Now I could breathe and enjoy the privelige of seeing our baby on the screen. There was a heartrate of 171 and the baby was very active, going through some kind of muy thai kickboxing routine, limbs punching and kicking imaginary exercise bags in the womb. It was a delightful experience.

After another blood test for K, we were ready to go, and the next six months stretched out before us. Until the screen it was impossible to look any further than that. Now we could let ourselves think about the world of possibilities ahead... names, bedroom furniture, how people would respond to the news, what will this little person grow up to be like, how we will do as parents, what our lives will be like, how much is it going to cost, schools, hobbies, the list goes on.... So much to think about, and all accompanied by an enormous sense of relief. Although there were more hurdles ahead, this was the biggest, at least to me. Finally we could admit to ourselves that we would parents, and in 10 days we would admit all that to our families too.