26/11/2009 12:57 GMT | Updated 22/05/2015 06:12 BST

Up The Duff - Introducing The Bump To Its Grandparents

What happens when you're 37, almost infertile, in a new relationship and you go and get pregnant by accident? Find out in Sarah's weekly column: Up the Duff Without a Paddle.

I'm sitting on a train as I write this, on my way to the Yorkshire Dales via a whistlestop visit to my parents. It's the first time they've seen me in the last three months, so the first time they will see The Bump. I'm now four months pregnant and definitely showing.

Like me, my parents are still stunned and slightly disbelieving that I'm actually having a baby. Like me, they've spent the last three years believing all of the pre-emptive fertility test results that said I would find it very difficult to conceive naturally due to low ovarian reserve, beyond the average for my biological age (37).

Now that my body is changing, and the evidence that I'm up the duff is here in front of me, literally, every day, I'm slowly getting my head around the idea that I'm going to be a mum. And when Dad picks me up on the station platform in two hours and twenty minutes I think the sight of me, his petite size 8 daughter sporting a healthy football-sized frontage, will rapidly get his head around it too.

This week has seemed to be mostly about my body, probably because of the hot weather and the imminent weekend break, for which I had to choose swimwear. The change in my shape is amazing and scary at the same time.

I ventured out to the fantastic Brockwell Lido this week, my first time in public in a bikini since being pregnant, and the response from others was fascinating. Little girls were transfixed by my shape, mums smiled at me, and guys seemed to enjoy the curves too -- probably thanks to the new DD-cup boobs. I did the pencil test yesterday, and let's just say I didn't have enough pencils. W.H.Smith probably doesn't have enough pencils.

I'm oiling the bump each day and it feels amazing. The sight of it clothed is equally wonderful, and I feel immensely proud of it when I'm out and about. So much so that on days when I wear baggier clothes I feel cheated of the chance to show off. You see, I never thought I would be one of those lucky pregnant women.

I must admit to feeling a bit shy of my changing shape in the bedroom department, though. Up until now I've been fairly relaxed about my body. I'm no Elle McPherson, but I've been blessed with being naturally slim all of my life, and partners have been very complimentary. This one is too, but I still feel a little awkward. Is that normal?

Elsewhere, a not terribly tactful friend of mine, a bloke, pointed out my swollen feet the other day, but it was scorching hot. My nipples are larger (come back rosebuds!) and I'm finding that my skin is more troublesome -- it feels gritty on my back and chest, more spotty on my face and I've found thread-like veiny things showing on my legs.

The good news is I don't care too much about any of these things. I'm too in awe of what's happening on the inside. Geez, I'm growing a baby and a new organ! If the acne gets too bad I'll just have to cancel that Vogue cover shoot...

Read more of Sarah's Thursday columns here.