If the umbilical cord has a low pH when a baby is born, he/she has a higher risk of infant death, developing cerebral palsy in childhood, and brain damage, according to a study carried out by researchers in Birmingham, England.
The study has been published in the British Medical Journal (BMJ), and is the first BMJ research paper to carry a continuing medical education (CME) credit through a new collaboration between the BMJ and Cleveland Clinic.
The researchers say their findings justify increased monitoring of babies born with a low cord Ph. They add that further research is needed to determine whether all newborns should have their umbilical cord blood tested.
Doctors have believed for some time that there might be an association between umbilical artery pH and adverse outcomes, because most babies who are deprived of oxygen (hypoxia) during labor have a low Ph of blood in their umbilical cord. Premature and very small babies are at high risk of hypoxia, a common cause of brain damage.
However, to date evidence for such a link has not been consistent. Current guidelines also question whether umbilical artery pH can accurately predict infant death or the development of cerebral palsy.
So, a team of scientists based in Birmingham, England examined the results of 51 studies, consisting of nearly half a million babies, to assess how compelling the link might be. Study quality was variable, but this did not seem to influence the overall results.
They found that low arterial umbilical cord pH had a strong and consistent association with infant death and brain damage as well as cerebral palsy in childhood.
Based on these findings, they call for increased surveillance of babies born with a low arterial cord pH, and for further research to explore the cost effectiveness of doing this test in all babies.
James Neilson, Professor of Obstetrics and Gynecology at the University of Liverpool, in an accompanying editorial, says that, given the findings of this study, “we should aim to reduce the number of babies born with a low cord pH, without increasing unnecessary obstetric intervention.”
Neilson hopes that this can be accomplished by more hands-on input to labor ward care by trained obstetric specialists and the use of computerized intelligent systems to guide decision making by obstetricians and midwives.
Meanwhile, he agrees with existing recommendations that umbilical cord blood should only be tested when there has been concern about the infant either in labor or directly following birth.
Gemma L Malin, Rachel K Morris, Khalid S Khan
Editorial: “Umbilical cord blood gas analysis”
James P Neilson