How do you tell your kids that you're having a baby, without them feeling somehow supplanted?
It's no exaggeration to say that I suffered sleepless nights about how to break the baby news to our children.
For some reason I had convinced myself that the prospect of having a baby brother or sister would seem seriously uncool to my sons, aged six and eight at the time.
I had this notion that, being boys, they would find babies eye-rollingly boring.
I also thought the age gap might make them feel like a baby would cramp their style or curb their fun.
And don't even get me started on my anxiety about how we'd ever enjoy a family trip to the cinema, never mind a holiday again. What teenage boy is ever going to want to watch the same film as his three-year-old sibling, and how can you plan a holiday that caters for older siblings as well as a baby?
Then there's the whole issue of my rambunctious, high-energy lads having to put up with their mother growing slow and rotund - the very time when they want to be at their most busy and active.
In fact my anxiety about how my children would react to the news of their new baby sibling started to get quite out of hand. It reached the point where I'd find myself thinking obsessively about the baby, feeling a low-level, constantly-pulsing sense of guilt. I could barely look the boys in the eyes without a nagging sense that I was about to ruin their childhood forever.
It didn't help that the all day and all night 'morning' sickness was making me lose the will to live either, and the confused, pitying glances that my sons started throwing my way only aggravated my sense that in becoming a mother again, I was somehow in danger of losing touch with the children I already have.
But I remember going through something similar when I found out I was pregnant with our second child, just after my firstborn's first birthday.
My gloriously smiley baby boy would toddle up to me all wide-eyed and full of wonder, and instead of embracing the moment and relishing the joy of knowing that he was going to make a great big brother, I'd find myself weeping ruinously in the bathroom and wailing to my husband that we were about to ruin our child's perfect little world.
Seriously, I wish the husband had uttered a rousing 'Pfft!' and told me to get a grip.
Because as it turned out, becoming a big brother was just about the coolest thing ever to have happened to our son, although he wouldn't always admit that, especially not at 8am on the average Monday when the boys are invariably squabbling over the same single precious Lego brick despite the prevalence of millions of the sodding things in our house.
And in the end, I needn't have worried about telling the boys about their baby brother or sister because their reaction took my breath away, and taught me a thing or two about how much I underestimate my lads.
Funnily enough, before I'd even realised I was pregnant I noticed my sons staring in rapture at a cute baby girl at the airport when we were on the way to visit relatives for New Year's Eve. There followed, to my surprise, a whole conversation about how desperately the boys would love a baby brother or sister. I couldn't believe my ears, but looking back I like to believe that it was a touch of the sort of happy synchronicity that helps everyone adjust to something as life-changing and potentially overwhelming as the arrival of a new baby.
In the end we decided to tell the children about the baby in a flurry of spontaneity, when the worrying had threatened to engulf me. Squashed together on the sofa, my husband broke the news sweetly to them, anchoring the whole conversation around that baby at the airport who had so captured their attention.
Instead of shrieking in disdain they were overjoyed, and from the minute they knew about the existence of their baby sibling they seemed to be in love with the idea of him or her.
After all that angst, my sons' reactions to the news that they are going to be big brothers was just perfect. In fact I'd go so far as to say that their delight in this baby has unravelled me - in a good way - and allowed me to fall in love with the idea of becoming a mum all over again, instead of just feeling worried or overwhelmed at the prospect of being outnumbered and over the hill.
My kids helped me see that our new baby is indeed a treasure and a blessing, not a cause for worry or concern. It's amazing how children can surprise us; seeing the best in the very situations that we expect them to most struggle with.
It seems entirely fitting that my children's joy at becoming big brothers has helped me find my own deeper sense of delight at being pregnant.
Sometimes it really seems as though my kids have taught me everything I know.
You can catch up on previous Outnumbered and Over the Hill columns here.