So Harper was born on 5 August. She turned out not to be a boy. She did not pop out like a wet piglet. She is a lovely looking thing, though I have to admit she does look a bit like a boy. In knitwear, she looks like Gordon Ramsay in a matinee jacket. Never mention this to her.

I promise this is the last labour story you will ever hear from me: of course I totally jinxed myself by going on and on and on about wanting an epidural, as though it was a given that I was such an old hand, such a natural at this sort of thing, that nothing could go wrong and my only conceivable worry would be pain relief. (My stepmother, a week before, gestured towards my beam area and said, "If that wasn't built for childbirth, I don't know what was." And so convinced was I that it would all go swimmingly, I forgot even to be cross with her. Well, of course I'm cross with her now: there's no expiry date on this kind of thing.)

As if all that wasn't jinx enough, I had a pedicure, and my best friend J said, "You're not supposed to do that when you're about to have a baby." I blithely came back with, "That's only so they can check that your toes aren't blue if you have an emergency caesarean and an anaesthetic," like that was an absurd course of events and only a total incompetent would ever embark upon it. She did give me a look which said – if I'm not misremembering the translation – "Are you absolutely sure you want to be such an arse?"

Sure enough, a week later, there I was with my fancy toes and three surgeons removing a baby from the not-designated exit. Ladies, caesareans are not the posh option. That whole too-posh-to-push thing is nuts; it is no less insane than saying, "I am too posh to have sex. I would rather be stabbed in my kidney." I have done it both ways, and I tell you from the bottom of my heart, with absolutely no new-age backwash about natural childbirth being beautiful (it really isn't), the c-section is a savagely weird operation. It leaves you with pains so systemic and mysterious that you spend the next two weeks wondering whether they remembered to put both your kidneys back in. And the scar isn't even straight, it's curved like a hideous smile. If I stuck two fish eyes on to my stomach, I could sell my body for Halloween.

The morning after, the obstetrician came round. I think he had mistaken me for an old hippy who wanted a homebirth – perhaps because I am old – because he quite sternly said, "This delivery never would have happened naturally. If you'd been at home, you would have been in real trouble."

"I never wanted her at home," I replied. "Pretty much the only thing to be said for this whole performance is that my waters didn't break on my own carpet." "Really?" he said, diverted momentarily from the tedium of his rounds by the possibility that I might be mad. "The only thing?" "Well, no, no," I corrected, "the only thing apart from this beautiful baby." And she is beautiful. Little Gordonella.

People say one of two things about their second child – either it's much, much easier, or it's much, much harder (you'll notice nobody ever says "It's the same as having one, except there are two . . . think of the difference between a hamburger and a Quarter Pounder." Understatement. That's the first thing you lose, upon becoming a parent.) I can settle this, of course: one minute it's a million times easier, the next minute it's a million times harder. Leaving hospital was easier, and driving home was a lot faster. All that business where you think strangers will probably try to steal your baby, and you drive at 10mph and you have to keep stopping in case there's carbon monoxide poisoning in the back of the vehicle . . . you don't get that the second time. And that's what is so toweringly difficult the first time, when you have spent your whole life thinking, gah, what's the worst that could happen? and suddenly you're thinking the worst? The worst is that he could choke on the top popper of his babygrow, and then I would have to kill myself, but because everybody would know I wanted to commit suicide I would have to find some incredibly fast and foolproof way of doing it. I'd probably have to get a gun . . . So that means getting a gun licence. So I'd have to join a gun club . . . Right, I could save myself some time by joining a gun club now . . .

It's surprisingly time consuming, making the transition from carefree to neurotic. But once you've done it, at least you don't have to do it twice.

Arriving home was harder. You tell yourself a load of bollocks while you're pregnant, about how the oldest one will take it. I took the view that T's emotional range would be circumscribed by his limited language ("Mummy", "Daddy", "Spot" and "toot toot", plus the times he said complicated things such as "remote control" and nobody believed me). He wouldn't know what "dethroned" and "supplanted" and "total stab in the back" even meant. It didn't work quite like that. Apparently, the human consciousness doesn't need a large vocabulary to notice that a new sibling isn't the untrammelled boon it's billed as. That bit is terrible. It's absolutely hideous watching disappointment on a first-born's face, even though I did read once that the whole aim of parenting was to introduce successive disappointments in an age-appropriate way, so that you were able, finally, to present the world with an adult who had been wholly disappointed, from every angle, by everything.

From a practical point of view, I guess the second one is easier – we have all the hardware and the brightly coloured plastic, and the house is full of very loud, stimulating noises. First-borns are swindled out of consumer options because their parents only ­ notice what they need precisely two weeks after they needed it. I would think it's more fun to be a second-born. What would have been good, as well as the blankets and Whoozits and socks, would be if I had retained any practical memories from last time, and assembled them into a skill set. I can't remember anything about babies: how to hold one, how to dress one, when you are meant to start giving them a bath, how long they can get away with a babygrow rather than an outfit, when they lose their chin-dimple (do they ever? Gordon Ramsay didn't) . . .

I had forgotten that funny, flickering smile they do when they're asleep, and the way they punch the air like Superbaby when they have finished eating, and throw their little heads back like they're drunk. I have totally forgotten how to breastfeed in public without taking all my clothes off; I have lost all that elaborate origami where your baby has latched on without anybody seeing anything (now I am asking myself what the chances are that I ever mastered that). I've forgotten that when you have a newborn, and you see a four-month-old, there is a lunatic but very audible part of you saying "I never want her to get that big, I want her to stay like this forever," even though she now has milk spots on every visible inch of skin, and truthfully, the people you think want to cuddle her are rearing away.

I have this distant memory of landmarks – such as the first time I tried to make T sleep in the evening or sleep in a cot – but I can't remember, even vaguely, when these landmarks occurred; they could have been at six weeks or six months. This is no more use to me than any of the other rubbish I have filled my head with – the plot of The Bodyguard or how to stain a boiled egg with the imprint of a primrose.

It's bittersweet this time around because I know I'll never see this phase again, and I know how short it is. I have set up this mournful counting-chorus – "This is the last time I will ever have a four-day-old baby, and now, it's the last time I'll ever have a five-day-old baby" etc. You spend so much time worrying about the tiny baby stage, with its amazing range of terrible things that can happen, followed by the mountain of things that don't sound terrible but in fact are (eczema, colic, a tongue tie, a highly strung or frightened nature – it all sounds pretty trivial, I imagine, but this is the stuff that ravages households) that you forget that when nothing does go wrong, it's quite magical and dreamlike. And then, almost immediately, it's over. They stop smelling of baby and start smelling of frankfurters, and life resumes, with another person in it. The more you tell yourself to appreciate the beginning bit, the more you blot it out with the regret of its passing.

Unless you have three, that is. Which I'm definitely not gonna. Tomorrow I'm going to get myself spayed.