I turned 40 recently, so had cause to look back over the past 10 years, as you do. During my 30s, I published four novels and had two children. Busy decade. It could have been a lot busier. In between my two children, I also found time to fit in three miscarriages - and I still find it peculiar to think that I have had a total of five pregnancies. Five. For a woman who entered her 30s certain that she didn't want children at all, that isn't bad going.

Motherhood came as something of a shock (to put it mildly). I was under contract to finish my third novel and had already spent the money on buying a flat to have the baby in. Although we both wanted a second child eventually, I insisted on a long gap before we started trying again. When we did, I was pregnant within a couple of months and all of my smug remarks about being Mrs Fertile seemed fully justified.

When I lost that second baby, at 10 weeks, it came as a terrible shock. What could have gone wrong? It just wasn't the sort of thing that happened to me. Physically, it was the most traumatic event I had been through since the birth of my child. The pain was every bit as bad, despite the fact that a doctor I had visited when I began to bleed had said, "Oh don't worry, if you do miscarry it will be just like a heavy period." At 10 weeks, I delivered a sac the size of a table-tennis ball with a complete embryo inside it. Of the many women friends I have spoken to, none has ever said her miscarriage was just like a heavy period.

We were living in Canada at the time, where I had a writers' residency at the Banff Centre in Alberta. When we got home and started telling people, they would say, "It must have been difficult, being so far from home." The reverse was true. Because we were abroad, we had told no one I was pregnant, which made it much, much easier.

Even so, I found the crassness of people's reactions surprising. The most common response I got from friends and family was, "Oh, well, at least you've got one already." I did not feel that having a child made my miscarriage easier - on the contrary. I knew exactly what I had lost. I knew what it smelled like, how it embraced. We had explained to our daughter what had happened and for some weeks she was in the habit of bringing me her favourite cuddly toys to hold at unexpected moments, "because you haven't got a baby in your tummy any more".

To make things worse, we returned home from Canada to find that most of our peer group seemed to be expecting their second child. Among our immediate acquaintances, we had been the first to have a baby, and had got used to being slightly ahead, the knowledgeable ones. Now we were being overtaken by friends who would announce their second pregnancies with a coy flourish and a sideways look at me, to see how I was taking it. This awkwardness worsened as our first child grew older and I went on to have a second and then a third miscarriage. The only people I could bear to talk to were other women to whom the same had happened, and I began to despise women who hadn't been through it.

The second miscarriage was the easiest, occurring only a few days after I had found out I was pregnant. After that it took me six long months to become pregnant again. Six months might not seem like much to women trying to conceive in the first place, but after two miscarriages it seemed like an age to me. By the time it came to my third miscarriage I felt like an old hand. When I started bleeding at eight weeks, I went straight to the early pregnancy unit at University College Hospital in London. A scan confirmed that there was no heartbeat. From the size of the embryo, they estimated that my baby had died two weeks earlier. I held the little black-and-white picture they gave me. "Look," I whispered, disbelievingly, "it really did exist."

It was easier to expel the embryo knowing the baby was dead already. After my first miscarriage, I could not shake the thought that my body had let go of a healthy, living child - that there was something catastrophically wrong with me that meant I had been incapable of protecting my unborn baby from simple gravity. I was 37 and wondering if I just wasn't meant to have a second child.

Having taken six months to get pregnant the fourth time around I was floored - and unprepared - when I found myself pregnant again immediately after my third miscarriage. By the time my second daughter arrived, compact and perfect as a plum, it felt as though I had been pregnant for years. I had plenty of scans during that pregnancy but I still did not believe my baby was real until I held her in my arms.

I wouldn't have had this wonderful second child if any of my three truncated pregnancies had proceeded. My partner thinks that what we have is perfect and it could not have turned out any other way. I don't feel that, entirely. The gap between my two girls is nearly five years, wide enough for people to comment on in the playground. My partner and I are both the middle child of three. It does sometimes feel as though there is a hole in our family.

I am painfully aware that there are women reading this who will have gone through multiple miscarriages and never been able to have a child - but I also tire of being made to feel that having two lovely children means I am not entitled to mourn the babies that didn't happen. The first child I lost would have turned three in the summer. There is a three-year-old ghost that pounds up and down the stairs of our home.

· www.babyloss.com, Miscarriage Association Helpline: 01924 200799. Louise Doughty's most recent novel is Fires in the Dark, published by Simon & Schuster.