Today's parents-to-be who have to make a multitude of decisions over the pregnancy and birth now face another dilemma over the first treatment their newborn will receive.

Vitamin K is given to new babies to protect them against haemorrhagic disease, a dangerous bleeding disorder. Yet doctors disagree and hospital policies differ over how it should be administered.

Giving vitamin K by injection - the traditional method - virtually eliminates any risk of abnormal bleeding. But in 1992 a study from Bristol University, published in the British Medical Journal, suggested injections might double the risk of childhood cancer. The Bristol research was criticised as having several shortcomings and three further studies from Sweden, the US and Denmark, all published the following year, found no such link.

All the same the British Paediatric Association recommended that all hospitals switched to giving vitamin K by mouth, a policy that has been fraught with problems. There is no licensed vitamin K product available for oral use in babies, and many GPs and health visitors have been reluctant to prescribe or administer an unlicensed drug. The result is that many breast-fed babies have not been getting the two follow-up doses of oral vitamin K recommended by the BPA. (Bottle-fed babies need only one oral dose, given at birth, because formula has vitamin K added.)

Doctors are also concerned about the effectiveness of oral vitamin K. The latest study, from Germany, also published in the BMJ, showed 18 out of 20 cases of haemorrhagic disease occurred in babies given oral vitamin K. As a result, some hospitals still give vitamin K by injection, others give it by mouth, while a few offer parents the choice. But according to a survey by the National Childbirth Trust, parents are not given adequate information about either route: the first many hear about vitamin K is during labour or just after delivery.

Three further studies of the possible link between vitamin K injections and cancer, two from Britain and one from Germany, are expected to be published later this year. With any luck they might resolve the current uncertainty. In the meantime what should parents do?

Doctor Andrew McNinch, a member of the BPA's working group on vitamin K and consultant paediatrician at the Royal Devon and Exeter Hospital, says they should consent to vitamin K treatment in one form or another. Although extremely rare - one estimate puts the risk at one in 10,000 without vitamin K treatment - haemorrhagic disease, or vitamin K deficiency bleeding as it is now called, can cause brain damage and death. Pregnant women should also ask about the hospital's policy well before the birth.

Dr McNinch also advises new parents to be alert. "Unexplained bleeding or a nose bleed in a baby should be investigated," he says. And although breast milk contains less vitamin K than formula, new mothers, he stresses, should not be put off breast-feeding, which is still considered the ideal by paediatricians.