We're opting to have children later and later. In England, the number of babies born to women over 45 has risen by a third since 2009. But are the statistics, and the increasing normalcy of egg freezing, clouding our perspective on the realities of having - or attempting to have - a baby over the age of 35? Australian novelist Julia Leigh, who underwent six cycles of unsuccessful fertility treatment between the ages of 38 and 44, aims to redress the balance with Avalanche: A Love Story, her searingly honest and, at times, heartbreakingly funny, memoir of the trials and tribulations of 'assisted reproduction'. We speak to her to discover how she has fared since the book was written, her feelings toward the IVF industry and what she would say to someone considering or undergoing treatment.

What motivated you to write the book?

I've tried to tell an intensely personal story about a common experience that has largely remained unspoken. I wanted to transmit what it feels like to be on the so-called IVF emotional rollercoaster and I guess I wanted to offer a shared aloneness to anyone who's desperately longed for a child. There are so many positive miracle stories out there about the success of IVF but the reality is that a great deal of IVF fails. I wanted to provide an alternative story to what we see so frequently in the media.

Do you think that the disproportionate number of 'happy ending' IVF stories in the media is misleading?

I do think that there is a bias towards the happy ending stories - a strong bias - because what many people might not realise is that most assisted reproduction treatment cycles fail. To give you an idea of the numbers, in the case of the most recent data available in Australia - and I'm sure it's similar in the UK - they looked at roughly 71,000 treatment cycles in a particular year and of those, about 80% did not result in a live birth.

Clinics tend to put a graph up on their websites showing how your fertility declines with age - the tricky thing is that once you begin your treatment it's very easy to kid yourself that you are going to be lucky. If you find that you are responding well to fertility drugs, for example - some women your age may not respond well to drugs but you may be a good responder. And the next step is in the lab, in the petri dish where your embryos are developing - you may find that your embryos are developing very well, whereas other women your age, their embryos might not be developing - so you might kid yourself that you've lifted out of the average figure for your age, and that's when things can get misleading.

I'll give you an example. When I was 43, and I was transferring a thawed 5 day blastocyst, I asked my doctor, "What are my odds of being pregnant?" - note that that's a pregnancy number I'm asking for, not a live birth number - and my doctor replied that a day 5 blastocyst has about a 40% chance. So I took that to mean that I had about a 40% chance of being pregnant. But later on I discovered that that 40% figure was for women of all ages, not for women of my age, so that's an example of how statistics can be malleable. I do worry about the practice of giving patients an overly optimistic outlook. Do you think that the IVF industry is inherently unethical?

I certainly would not go that far - I acknowledge that many people's lives have been transformed and filled with love. But I do think that the IVF industry is aggressively marketed, I do think that statistics are malleable and I'm concerned that patients [in Australia] are routinely offered add-on treatments that are not strongly supported by evidence. What advice would you give to someone undergoing treatment?

I think patients and doctors alike minimise the physical, emotional and financial toll of IVF. In my case, I kidded myself that, "well, I'll try it and if it doesn't work I'll be restored to the position I was in when I started," but in fact, by the end, I was brought much lower - I was a complete wreck. So I think we should talk openly about the harms of the process.

Did you find writing the book a cathartic experience?

Yes, I found it helpful, and in an unexpected way as well - it brought me closer to my friends who didn't really know what was involved with the world of IVF. I wrote this book for women who are thinking about IVF or who are doing it - especially those who are facing the difficult decision about when to give up - but I also wrote it for the family and friends. You know, it's a hard thing to talk about and I hope this just opens up the discussion a bit more.

You're very open about your experience in the book - did you have any qualms about exposing the details of your relationships with your ex-husband and other significant people in your life?

I have been very open - I guess I thought, "if you're going to write a personal story you might as well go all the way - you might as well go 'all in', as we say in poker". I'd already lost so much that at the time I wrote it I wasn't concerned about losing face, and that did give me a unique freedom. You make several references to meditation and mindfulness-related concepts in the book. Is that something that you found helpful during the treatment process?

The funny thing is that I do have a background in mindfulness practices but I have to confess that I couldn't really apply them - I tried, but I found myself completely in the grip of this strong desire to have a child. Have you returned to it since your treatment ended?

Yes, I'm trying to - bit by bit, little by little.

You end the book by talking about your commitment to transform the love you wanted to give to your child into a wider, more all-embracing kind of love. Have you managed to maintain this?

I really believe in that commitment and I have been brought closer, as I said, to my friends and my family, and I of course have my nieces and nephews who I adore, but yes, in terms of thinking of love in even broader terms than one's immediate circle, that is something that I think will be an ongoing, lifelong practice.

IVF can be a very isolating experience - do you think this sense of a wider social connectedness could help women to counter that?

Yes I do, and I think that the more we share our personal stories, the better. I would encourage couples and women who are on this journey to share some of their experiences with the people around them. I know it's very hard because I myself found it very hard to talk about with others for a range of reasons that I share in the book, but I think it's a special thing to share these kinds of vulnerable stories.

Have things changed for you on a personal level since you finished writing the book? Do you still have to take care not to expose yourself to painful situations, like grocery shopping at 3.30pm?

That one is no longer an issue but I confess I did avoid my 5-year-old niece's birthday party where all the kids and all the parents would be - instead we had a separate little gathering.

Avalanche: A Love Story by Julia Leigh is published by Faber & Faber, £12.99