Doctors are failing to spot dangerous breech pregnancies because standard physical examinations involving feeling the bump are not sensitive enough, according to researchers.
A study of 1,600 women found doctors are missing about a third of breech pregnancies, which often result in risky emergency caesarean sections. The researchers say doctors should consider using ultrasound scans to diagnose the baby's position as a matter of course.
Breech babies come out buttocks first rather than head first. It occurs in 3-4% of pregnancies and can lead to constriction of the umbilical cord, which starves the baby of oxygen and can lead to brain damage or death.
Even worse are horizontal or obliquely lying babies, about one in 2,500 births. In all cases, if the abnormal position is discovered during labour an emergency caesarean is the only option, entailing a risk of infection and blood loss.
Emily Olive, an obstetrician at the University of Sydney, and colleagues studied more than 1,600 deliveries to assess the effectiveness of the standard method of diagnosing breech births. Called palpation, this involves the doctor essentially feeling the bump.
The team, reporting in the British Medical Journal, found that the technique missed about 30% of breech babies.
Dr Olive said that if an ultrasound scan is available it should be used to identify breech babies well before the birth. "The problem with not diagnosing the breech until labour is that the woman really loses her choices," she said.
One remedy involves the obstetrician manipulating the baby's position using pressure on the mother's stomach, successful in about 50% of cases. Failing that, a planned caesarean is less risky than a last-minute operation.
Women in the UK typically have an ultrasound scan at 12 weeks and another at 20 weeks. Adding a third would be costly, so the authors say a cost-benefit analysis should be undertaken to see whether routine scanning is worthwhile.
"The main issues associated with the introduction of routine ultrasound are the availability of ultrasound machines, resources and people adequately skilled in conducting the scans in each clinical setting," said co-author Natasha Nassar. There is also a fear that, if it is introduced as routine, clinical staff will lose the palpation skill.
The authors say there is no evidence that increasing the number of scans will harm babies, and Bruce Ramsay, a consultant obstetrician and spokesman for the Royal College of Obstetricians and Gynaecologists, said it might be tried with obese women, with whom palpation is particularly unsuccessful.
"As obesity becomes more prevalent this will become an increasing problem," Dr Olive said.
