"Birth is only safe in retrospect" must be the statement most often used to justify a medically defensive approach to delivering a baby. It is a bit like saying, "Today is only safe in retrospect" to justify not leaving the house. We all have to accept some risks in life and giving birth is part of living.

Birth is a physical and mental challenge for a woman, as well as an enormous transition in her life. But the number of healthy women who die as a direct result of childbirth is almost non-existent. For a healthy woman with a normal pregnancy and no existing medical problems, the safest way to give birth is vaginally and with no intervention, unless there is a clear medical reason to do otherwise or it is requested by the woman.

The way to help a woman to give birth and come away from the experience physically and mentally well, and with joyful memories that will sustain her through the challenges of motherhood, is to provide her with a private, non-medical space, with a midwife who will stay by her side for the duration of her labour. A midwife who is skilled and understands the value of enabling a woman to give birth herself. A midwife who knows what a normal birth is and can quickly tell if medical attention is needed. A midwife who will seek the help of an experienced obstetrician directly she feels it is required.

A healthy woman who has had a normal pregnancy and who is able to give birth in a place in which she feels comfortable and well supported is likely to find that medical intervention is not balanced by improved outcomes. Instead, one intervention is likely to lead to another - an epidural to a forceps and an episiotomy, which can lead to a longer recovery, and so on.

Defensive practice, such as a caesarean, is also considered justified for the sake of the baby. The risks to a woman are judged acceptable in order to save her baby's life. Women repeatedly show they will accept an increased risk to themselves to improve the chances for their baby. Yet the evidence demonstrates that, for most babies, the safest birth is a straightforward vaginal birth, unless there are clear medical indications to the contrary.

A caesarean not only carries increased risks to a woman and her baby compared to a vaginal birth, the risk to mother and baby in a subsequent pregnancy also is higher after the procedure. Such risks can only be acceptable when they are outweighed by clear medical benefits to the mother or baby.

The best way to practise defensive medicine, and to reduce the risk of litigation, is for our NHS - our managers, doctors and midwives - and society more widely to understand what systems, skills and values will give every healthy woman with a normal pregnancy the best chance of a straightforward birth. At the same time, medical practitioners need to become highly adept at offering the superb medical skills we have in the NHS to those women and babies who will benefit from them.

· Belinda Phipps is the chief executive of the National Childbirth Trust