Can MRI Predict Preterm Labor in Pregnant Women?

Diffusion-weighted MRI scans, traditionally used in abdominal and pelvic diseases, showed promise for predicting preterm labor in asymptomatic women with cervical incompetence in a small

European study.

Among eight women who delivered within 7 days of admission, apparent diffusion coefficient values obtained from MRI scans were significantly higher, on average, than among 22 women who

delivered more than 7 days post-admission, reported Gabrielle Masselli, MD, of Sapienza University in Rome, and colleagues in Radiology.

Sub-glandular values were inversely correlated with the interval between the imaging and delivery (r=-0.75).

"This study provides very preliminary data suggesting MRI might help in stratifying patients at risk for preterm labor based on a short cervix seen at prenatal ultrasound," Fergus V.

Coakley, MD, of Oregon Health & Science University in Portland and a member of the Radiological Society of North America, told MedPage Today.

Said Coakley, who was not involved in the study, "This might allow us to better pinpoint women at high risk of preterm labor and manage them more intensively."

Using MR imaging, Masselli's team calculated the apparent diffusion coefficient of the cervix, which measures the magnitude of diffusion of water molecules within tissue.

"The high [apparent diffusion coefficient] values recorded in the sub-glandular zone of the cervix in patients with impending delivery indicate a localized increased mobility of water

molecules," they wrote. "We believe that sub-glandular ADC analysis records the start of cervical ripening, a process of fast cervical remodeling limited to the few days preceding the start

of active labor."

The 30 participants had a mean gestational age of 26 weeks and all had a sonographic short cervix (≤15 mm). Those with delivery beyond 7 days from imaging delivered from 18 to 89 days later

(mean 55 days). All had a positive fetal fibronectin test suggesting a likelihood of preterm birth.

Overall, 19 of the 30 participants with cervical incompetence experienced a preterm delivery, defined as less than 32 weeks gestation.

Masselli and colleagues cautioned that their results needed to be confirmed in future studies.

"If this finding is confirmed in larger populations being studied for different risk factors, it could improve the policy of hospital admission and corticosteroid administration," they

wrote. "In addition, it could represent a new tool with which to monitor the efficacy of any drug putatively administered to slow the progression of impending labor."