There's so much pressure to do the right thing in pregnancy - don't smoke, don't drink, don't eat interesting cheeses.
Now this new study says moderate exercise three times a week is not only good for the woman, it's good for the baby too. Great - something else to feel guilty about...
It's a very small study – only 26 women took part – so the results have to be treated cautiously anyway.
In theory exercise in pregnancy sounds great - it's not an illness after all. I had every intention of carrying on running. Maybe not as much as Paula Radcliffe, who carried on running practically into the delivery suite.
But still, I thought it would be fine until well into the second trimester. I had read about it on the forums on my usual running website, Runners World, and was encouraged by how many women keep going.
In reality, I packed it in after about eight weeks of pregnancy because it felt so horrible. It may have been psychological but I felt really heavy already, was tired all the time, and morning sickness doesn't make you want to spring out of bed and jump into your trainers.
I was also worried about over-heating, which is supposed to be avoided during pregnancy.
However, this new study does count "moderate to vigorous walking" as exercise and I found walking much more acceptable. I don't know how you measure how vigorously you are walking, but believe me, it's all vigorous when you're in your third trimester!
I was still plodding up and down the pavements well past my due date, in the vain hope that gravity would help set labour off. It didn't work – I had to be induced – but I like to think the extra fitness helped during labour itself!
As for exercise after pregnancy, well, good luck finding the time and energy...