Statistics

A couple of weeks ago we got the results of Hayley’s screening test for downs syndrome. Her statistical chance of having an affected child was 1 in 410. This is about average for her age. We read the literature and considered whether a further test was appropriate. But the further test has a 1 in 100 chance of causing a miscarriage. On top of these numbers there are many other figures within the literature to try to clarify the likelihood of the possible outcomes.

We opted to continue without a further test, but I was struck by how confusing the mass of figures can be. I read several booklets and they sometimes gave conflicting figures. Even where they didn’t conflict their context was often vague, e.g. was the figure for all women across all age ranges and if so what was the distribution of ages within that group? I had to read and re-read the information several times before I was sure I had gleaned as much from it as I could. And even then, I was struck by the fact that the odds we were presented with were just that: odds. A measure of our chances in the lottery we’d opted into.

In the end we decided that we should proceed positively and (as Hayley’s GP said to her when she spoke to him about it) enjoy the pregnancy. There are (and will be in future) many possible problems and things that might go wrong. From now on we will have to learn to deal with them as they come along and try not to worry more than is reasonable. Something that I suspect is going to be particularly hard for Hayley, a born worrier!