Babies can get stuck in the pelvis

The device lets the doctor assess how much force they are using to manoeuvre the baby into a better position for a vaginal delivery.

This should help avoid unnecessary trauma to the mother and baby.

The device has already been tested during 15 real-life deliveries by the team from Johns Hopkins University.

We can measure what is happening to the baby during birth Lead researcher Dr Edith Gurewitsch

In about 5% of births, the baby's shoulders become stuck in the birth canal.

The delivering doctor can perform several different manoeuvres to free the baby safely.

But in about a quarter of these deliveries, the baby is injured by the handling.

Scientists and students at Johns Hopkins University set out to design a device that could monitor the amount of force being used to deliver a baby, in order to warn the doctor when he/she might be pulling too hard.

The device consists of three electrodes which are attached to the forearm of the doctor who is performing the delivery.

Difficult deliveries

The electrodes send information, via a small metal box that rests in the doctor's pocket, to a remote computer which stores and processes the data.

The device gives an accurate record of the force being used during delivery by comparing it to calibrated force readings for the individual user.

Dr Edith Gurewitsch, assistant professor of obstetrics and gynaecology at the university, said: "While further studies are necessary before we can make definitive recommendations on the use of one procedure over another, our initial laboratory results demonstrate that we can measure what is happening to the baby during birth, and we can alter our technique to create a safer environment for delivery."

When they performed 30 mock deliveries, using three-dimensional models of the mother's pelvis and a baby, the team found turning the baby so its spine faces the mother's belly was the safest way to proceed if the baby's shoulders were stuck in the birth canal.

This manoeuvre was associated with the least amount of force - 6.5 pounds - to the baby's head necessary to achieve delivery.

In comparison, turning the baby so its spine faced the mother's spine applied 8.5 pounds and moving the mother's legs back to widen the pelvis applied 16 pounds.

Dr Gurewitsch has been using the device clinically, and believes it could help train future doctors and midwives.

Dr Shagaf Bakour, consultant obstetrician and gynaecologist at City Hospital in Birmingham, said: "It could have an important role in the practical training of junior obstetricians in their structured postgraduate training.

"It would allow the trainee to acquire a personal experience in dealing with shoulder dystocia - every obstetrician's nightmare - not only imagining it."