There is a long pause. "You look very doubtful," ponders the sixtysomething social anthropologist, who for more than 30 years has researched and written on childbirth around the world. She lays out her hands, as if to explain. "Imagine a woman is in second-stage labour but instead of everyone telling her to hold her breath, push and count to 10, she is synchronised with her body, in the moment, doing exactly what her body tells her. The breathing that you hear at a time like this - in Third World countries and here, too - is very like the breathing of sexual excitement and orgasm." With which Kitzinger starts to demonstrate what she means. Twice, at full, lusty tilt, lasting a good couple of minutes, and in clear hearing of the other customers of the Hanover Cafe, this rosy-cheeked grandmother in a patchwork jacket fakes - er - second-stage labour. As it was a dead- ringer for the pants and sighs of Meg Ryan's faked orgasm in the infamous deli scene in When Harry Met Sally, I could now see the connection. Though I had to wonder what the waiter made of us.
Such unorthodox behaviour rather endeared me to the grand old guru of natural childbirth. She really does want to get in there - on the hard mud floor of the African hut or splashing about in the birthing pool at your local NHS hospital - and share the experience that results in women becoming mothers. It's just that she seems to have such high expectations of it all: birth as some kind of sexual ecstasy? When I told my nanny, whose own labour is still fresh in her mind, what Kitzinger had said, she quipped: "The woman needs a bullet."
The author of 30 books, Kitzinger claims she is not a proselytiser for natural childbirth, but a reporter of women's experience: "It's not a question of what I say, it's a question of what the women I'm talking to say. I need to be a channel for what they're thinking." But when you try to ask who exactly - as they don't seem to match up with many of the women's experiences I've heard - you get something like this: "There are many women for whom birth is a deeply satisfying and joyful experience." To which, I feel I must counter, there are many for whom it is very painful, and often this is not helped by the natural childbirth movement's negative approach to pain relief, such as epidurals and pethidine. Or the feeling that medical intervention is necessarily going to make birth a bad experience.
Kitzinger's language in the book is non-judgmental in the extreme, but it's pretty clear where her own feelings lie: "There are women who just want to get through labour, and I would support them. There are others who want more and I am keen to help them have that experience. But I would also support a woman who elected to have a Caesarean. Of course I would! It's her choice and it's important that a woman makes her own decisions. I would, however, if we had time, think it useful to talk through the pros and cons, because there are some disadvantages as well."
While she is desperately keen that no woman suffer any guilt or blame for bad childbirth experiences, she does not appear to have the same respect for doctors. How can a first-time mother know what is best? I ask. She has no experience. Neither do loads of house surgeons and junior doctors, she counters. "I think we should get away from this master/servant relationship. Obstetricians don't come possessed of a superhuman knowledge, you know."
She has a point. Before women like Kitzinger battled their way into the labour ward, birth was firmly in the hands of obstetricians, or midwives following their procedures. For example, episiotomy, in which a woman's perineum is cut to make delivery easier, was routine. After Kitzinger published a paper showing it was better to let the woman tear than cut her, the episiotomy rate in one hospital dropped from 70 per cent to under 40 in three weeks. "The midwives simply said to the doctors, why are we doing this? They had enough experience to see that women could do without this intervention."
Kitzinger introduced the birthplan - by which prospective mothers can rule out or insist upon various procedures during the labour - to Britain, but she is concerned that some women take it rather too literally. "I'm not starry-eyed about this. It's like if you plan a picnic in this country; you have to imagine what happens if it rains as well. The main point is that if women want to, they can share in the decision-making. If they don't want to, that's fine, too."
While some of her views could be predicted - you almost don't need to be told that she's pro-home birth and a promoter of the doulas system (which has Greek origins and involves the presence of women helpers during labour) - other questions bring more surprising answers. Kitzinger herself had five children, the last born 34 years ago. Were she to be pregnant today, she thinks she would probably resist the battery of tests that are now available.
"When I had my babies I never even thought about all the things that might be wrong with them. When I was pregnant with twins, I didn't know there were two of them until six weeks before the birth! But I speak to some women today who say they couldn't stand that uncertainty. I have to say that even if the baby is born perfect - as the vast majority are - something might happen to them in the early years anyway. There's always uncertainty."
Her worry is that because of ante-natal tests, pregnancy has become shorter, tenser. "Increasingly, women don't tell people they are pregnant until the other side of their "anomaly" scan after 16 weeks - hospitals vary. Because they feel they might want to terminate if they don't have a perfect baby." The pursuit of perfection also taints fertility treatment for Kitzinger. "This is a child we're talking about, not a factory product; I don't like this idea that babies are goods, that must be 100 per cent perfect or they are rejected." But wouldn't she, if she had not been able to conceive naturally, have gone down that route? "In my case, no. I would have thought that door hasn't opened, let's see what other doors there are."
And while I might disagree with a lot of what she says, I think we should be rather glad that Sheila Kitzinger clearly had such a wonderful time giving birth to her five children. "I think there are many women who enjoy giving birth - and I'm just happy to have deepened that capacity for joy."
The New Pregnancy And Childbirth by Sheila Kitzinger is published by Penguin (pounds 14.99). Louise Chunn is features director of Vogue.