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2007-9-3 17:29:25 |
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As many as one in four infants experienced bleeding in or around their brains soon after they were delivered vaginally, according to a new study published in the February issue of Radiology. "Small bleeds in and around the brain are very common in infants who are born vaginally," said John H. Gilmore, M.D., coauthor of the study at the University of North Carolina School of Medicine in Chapel Hill. Gilmore and colleagues suggested that the small bleeds are likely caused by the shifting of the bones of the skull, but they may not cause much harm in most of cases if any. For the study, Gilmore and team used magnetic resonance imaging (MRI) to study the brains of 44 asymptomatic female infants and 44 male infants between the ages of one and five weeks, 65 born vaginally and 23 by cesarean section. MR images showed that 26 percent of the babies delivered vaginally had so called intracranial hemorrhages (ICH), or small bleeds in and around the brain. Seven infants had two or more types of ICH. In comparison, none of the infants with bleeding had been delivered by C-section. The new findings differ from prior studies which have shown approximately 10 percent of intracranial hemorrhage was associated with vaginal birth. Earlier studies suggest that not all vaginal births experience the same risk of small bleeds, which may be determined by other risk factors such as vacuum extraction in addition to the vaginal pressure. In a study published in the November 2005 issue of British journal of obstetrics and gynecology, Boo N. Y. and colleagues from Hospital Univesiti Kebangsaan Malaysia reported that vacuum extraction was associated with subaponeurotic hemorrhage. But, the researchers said the bleeding examined in the current study was not due to prolonged duration of labor or on traumatic or assisted vaginal birth. "In our study, neither the size of the baby or the baby's head, the length of the labor, nor the use of vacuum or forceps to assist the delivery caused the bleeds," Dr. Gilmore said. "The bleeds are probably caused by pressure on the skull during delivery." The researchers explained that the bones of the skull in newborns are not fused, so they can shift and often overlap each other during vaginal delivery, compressing the brain and causing blood vessels to tear and bleed. But in most cases, the bleeding occurred between the brain and the thick membrane that covers the brain below the skull, the researchers noted. They said these small bleeds resolve over time without causing problems, but large ones may cause problems such as seizure, subtle learning problem or problem with motor development later in the child's life. "We just don't know at this time what these bleeds may mean over the long term," Dr. Gilmore said. More studies are needed to assess the long-term effects of ICH in infants. But Dr. Gilmore noted that these findings do not suggest that expectant parents should opt to abandon vaginal delivery for C-section. Experts say that C-section has its own problems as well. Other than probably harming the infants, the mothers are more likely to experience a series of physical problems including severe bleeding, blood clots and emergency hysterectomy, longer-lasting and more severe pain and infection compared to a vaginal birth. "Obviously, the vast majority of us who were born vaginally and may have had these types of bleeds are doing just fine," he said. "Humans have been born vaginally for a very long time, and our brains probably evolved to handle vaginal birth without major difficulty." Source: |
