Monday, August 20, 2007

Just a little bit pregnant

The average woman in Britain is 1 week pregnant

A back of the envelope calculation. A ball park figure

It goes like this:

  • 3/4 million babies born each year
  • add 1/4 million for pregnancies which end in abortion (medically induced or spontaneous miscarriage)
  • total population 60 million
  • so 30 million females
  • so 1 in 30 gets pregnant each year
  • average length of pregnancy 30 weeks, say, (to allow for premature births & all those which do not result in a live born child)

So, on any given day, any female (of any age) is, on average, 1 week pregnant

We could refine the calculation. Adjust it to apply just to females 'of child bearing age'. Make other adjustments to allow for women who could not possibly be pregnant

Its not a fundamentally silly calculation. Quite useful for thinking about the overall provision of maternal & antenatal services, for example

And vital to bear in mind before you submit any woman to X-ray radiation, or a job involving exposure to substances which may damage a foetus, or prescribing any drugs

But silly if applied unthinkingly to every female, in any circumstances. Cruel, even

The moral of this story is: Statistics apply to populations, they dont apply to individuals