New device promises safer deliveries

When the birth of a baby does not proceed smoothly, how much force should a
doctor or midwife apply? Students in the US think an unobtrusive device created during their studies could be the answer.

When the birth of a baby does not proceed smoothly, how much force should a doctor or midwife apply? If a complicated delivery takes too long, the child could suffocate, yet pulling too hard could injure the child.

To address this dilemma, Johns Hopkins University, Maryland, biomedical engineering students have invented an unobtrusive device that measures the amount of force a doctor or midwife uses while delivering a baby.

A wireless transmitter sends the data from the doctor to a computer across the delivery room. The system is already being tested at The Johns Hopkins Hospital, where researchers hope it eventually will help them identify the safest delivery method for a complicated birth. The inventors believe their device could also be used as a teaching tool, helping obstetricians-in-training learn how to assess the amount of force they use during a routine delivery.

The electromyographic instrument, which measures electrical impulses in the muscles of the forearm, was devised and constructed by a team of undergraduates during a semester-long biomedical engineering design team course.

The assignment that produced the device came from design course instructor Robert Allen, a senior lecturer in the Department of Biomedical Engineering. Allen and his obstetrics research colleagues have been looking for a method of measuring the force used in a delivery as a way to help determine the best technique to employ during complicated births.

Previously, inventors have placed sensors in gloves or on the hands, interfering with doctors’ grasp. Allen’s students came up with a less intrusive system, in which three electrodes are attached to the forearm and connected to a small metal box that rests in the doctor’s pocket. The box collects information from the electrodes and transmits it to a receiver up to 50 feet away. The receiver is connected to a laptop computer, which stores and processes the data.

Since April, when the students finished the project, Edith Gurewitsch, assistant professor of gynecology and obstetrics in the Johns Hopkins School of Medicine, has supervised an institutional review board-approved pilot study, testing the device during 15 deliveries performed by physicians and a midwife.

The participants wore the electrodes under sterile gowns and gloves. Although some fine-tuning has been required to ensure that the muscle impulses are detected by the electrodes, Gurewitsch said that device seems to work well.

The obstetrics researcher is also working with Allen and the Johns Hopkins student inventors, using the device in a lab in which mock deliveries are performed using a baby-size doll.

Generally, physicians or midwives apply minimal force on the child during a routine delivery. But Gurewitsch hopes to use the student-built device in her study of complicated deliveries in which the baby’s shoulder becomes stuck behind the pubic bone. Several different techniques can be used to extract the baby when this occurs.

‘Our ultimate goal is to use the device to figure out which is the best technique to use in these complicated deliveries,’ Gurewitsch said. ‘We want to find the technique that requires you to use the least amount of force.’

The device must be calibrated to each user. This is done either shortly before or after the delivery, when the physician or midwife’s forearm muscle impulses are recorded at rest and while pulling with five pounds of force, then 10 pounds, as measured by a dynamometer. The students’ device can then produce an accurate record of the force used during delivery by comparing it to the calibration readings.

The four students and Robert Allen have obtained a provisional patent covering their device.