Device detects preterm labor in pregnancy

JOHNS HOPKINS (US)—An invention designed to pick up very early signs that a woman is going into labor too soon could help doctors prevent premature births, its inventors say.

When a child is born too early, serious health problems for the baby and steep medical bills for the family can result.

“The problem is, the technology now used by most doctors usually detects preterm labor when it’s so far along that medications can only delay some of these births for a few days,” says Karin Hwang, one of the inventors and a biomedical engineering graduate student at Johns Hopkins University. “But if labor can be detected earlier, medications can sometimes prolong the pregnancy by as much as six weeks.”

Premature births have received increasing attention, due to a rise in the number of multiple births; to the use of fertility treatments, which can cause multiple births; and to an increase in women who are having babies later in life. These trends are all associated with a higher risk of preterm labor.

The National Center for Health Statistics has reported that about 500,000 premature live births occur annually in the United States alone. In a 2006 report, the Institute of Medicine described the high rate of premature births in the United States as “a public health concern that costs society at least $26 billion a year.”

Preterm births are widely linked to neonatal deaths or serious health problems such as breathing difficulties and brain development issues.

Hwang was one of four graduate students who devised and built the system. The students and their faculty sponsor, Abimbola Aina-Mumuney, an assistant professor of maternal fetal medicine at the Johns Hopkins School of Medicine, have formed a company to advance the project.

“I told them it’s really important to know at the earliest possible point when a pregnant patient is contracting,” Aina-Mumuney says. “It’s something I’ve had a strong interest in.”

The students initially proposed a blood test to find proteins associated with early labor, but Aina-Mumuney steered them toward building a better device to detect physical signals in the expectant mother’s body.

To find signs of preterm labor, physicians have long relied on a tocodynamometer, a belt attached to a woman’s abdomen for external monitoring of uterine contractions. But Aina-Mumuney said this device is not effective at picking up preterm labor very early in a pregnancy or in cases where the patient is obese.

“I suggested that the students come up with an internal device,” she says. “I told them that if we could bypass the abdomen, that would be ideal.”

After much research and brainstorming, the students built a prototype ring made of medical grade biocompatible silicone elastomer. The ring is designed to be compressed and inserted into the vaginal canal at a physician’s office or hospital. Embedded within the ring are sensors designed to pick up electrical signals associated with uterine contractions.

“With these sensors, we’re detecting signals directly from the places in the body where they originate, as opposed to trying to pick them up through the abdominal wall,” says Chris Courville, one of the inventors.

The prototype detector has not yet been used on human patients, but the students say early animal tests are promising and that improvement of the system is continuing.

“They can truly see the impact this could make,” says Aina-Mumuney. “If we can detect preterm labor at an earlier point and can delay the delivery by six weeks or more, the risk of the baby being born with serious health problems will go down dramatically.”

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