Infant brain hemorrhages can occur after normal vaginal births

March 13, 2007

Intracranial bleeding in newborns has been found common after a vaginal birth, although the bleeding is limited and apparently has no effect, according to researchers at the University of North Carolina School of Medicine.

Intracranial bleeding in newborns has been found common after a vaginal birth, although the bleeding is limited and apparently has no effect, according to researchers at the University of North Carolina School of Medicine.

In a study using magnetic resonance imaging, about one infant in four delivered vaginally had at least one form of intracranial hemorrhage.

John Gilmore, MD, and colleagues reported in the February issue of Radiology that MRI did not show signs of bleeding for babies born by caesarian delivery.

"Small bleeds in and around the brain are very common in infants who are born vaginally," Dr. Gilmore said. "It seems that a normal vaginal birth can cause these small bleeds."

But he added that although more research is needed on the implications of the hemorrhages, vaginal birth has not suddenly become unduly risky.

Intracranial hemorrhage in full-term infants is usually associated with symptoms such as apnea, bradycardia, and seizures, Dr. Gilmore said, and a range of factors has been suggested to account for the bleeding, including prolonged labor and assisted delivery.

But for this study, the researchers studied 88 asymptomatic newborns, evenly divided between male and female, of who 65 were delivered vaginally and the remainder by caesarian. The infants were studied using a 3-Tesla MR machine, without anesthetic, between the ages of one and five weeks.
Analysis found that:

  • Seventeen of the babies-or 26% of the cohort-had bleeding, including 16 subdural, two subarachnoid, one intraventricular, and six parenchymal hemorrhages

  • Seven infants had two or more types of bleeding

  • None of the infants with bleeding had been delivered by C-section

  • Intracranial bleeding was significantly associated with vaginal birth (at P<0.005) but not with prolonged duration of labor or with traumatic or assisted vaginal birth.

Typically, such small hemorrhages resolve over time without causing problems, the researchers said, although larger events may cause such problems such as seizures, learning disabilities, or problems with motor development. The author noted several limitations of the study that may have led to underestimates of the frequency of bleeding.

"The images were not obtained immediately after birth but in weeks one to five after birth, and, perhaps, we missed cases of intracerebral hemorrhage that had resolved. Also, our imaging protocol did not include T2-weighted or magnetic susceptibility-weighted images, which might be even more sensitive for depiction of hemorrhage." They also pointed out that "no follow-up images were obtained to determine imaging resolution of hemorrhage, and no clinical follow-up was performed after the identification of intracerebral hemorrhage."