Size doesn't matter, or does it?

"Oooh, haven't you got a tiny bump," said the midwife as Mrs B strolled in to her office for her 31-week check-up yesterday.

"Really? Oh," was  my wife's startled and instantly worried reaction.

It wasn't exactly the A to Z of Midwifing's text book way of putting a first-time mum at ease upon arrival at one's clinic. A plastic surgeon wouldn't, for example, welcome a nervous nose-job patient in to his surgery with the words; "Morning big nose."

Anyway, despite causing momentary panic for Mrs B, the midwife went on to explain that, although her bump was on the small side, all was well. A measurement was taken and it transpired that Baby B's bump measured 30 cm and, we were told, that anywhere 3cm either side of your number of weeks is fine. Cue a giant sigh of relief.

However, this has got me thinking - and searching Google images for comparitive 31-week bumps - and it does seem that, at this stage of pregnancy, bump sizes vary hugely. Friends of ours, for instance, visited us for lunch at 31-weeks pregnant and clearly, in my humble opinion, looked huge. Others, according to Google, are similarly petite.

Does this have any effect on baby size or sex? Apparently not. There are a huge number of factors that affect bump size; a woman's height and pre-pregnancy weight, the amount of exercise taken during pregnancy, the position of the baby; diet during pregnancy etc.

What I'd like to know, however, is whether genetics plays a real key. Mrs B is always on the phone to her mum discussing progress and takes comfort in hearing that her mum's pregnancies were very similar. My mum, meanwhile, revealed last night that I was in fact small but "long and lean" - something that hasn't changed much in the subsequent 33 years.

As for determining sex, however, our mum's are no help. My mother-in-law's small bumps resulted in two daughters, while I am one of three boys.

There is a chance, of course, that Baby B is saving him or herself for a final push as we head towards B-Day, so we're bracing ourselves for some serious bump expansion over the coming weeks.

Whatever happens, I'll be watching, tape measure in hand.