Hypoxic-ischemic encephalopathy (HIE) is a brain injury caused by insufficient oxygenated blood flow to the brain at or near the time of delivery. There are many potential causes of HIE, including high-risk pregnancy conditions, labor and delivery issues, and medical mistakes.
Recent studies have sought to find connections between placental and umbilical cord issues and HIE, so that the placenta can be studied at birth to aid in diagnosis.
In a 2016 study, 41 infants who had been treated with therapeutic hypothermia (TH) had their umbilical cords and placentas studied through histopathological analysis (1). These findings were tested against a control group of infants without HIE. This study found that velamentous or marginal umbilical cord insertions (both abnormal cord insertions) were found in 39 percent of the HIE cases and only 7 percent in the controls. Also, velamentous or marginal umbilical cord insertion and histological abruption (a study of placental tissues that confirms abruption) were found to be associated with risk of severe HIE. The results of this study are suggestive of the profound association between umbilical cord and placental abnormalities with HIE (1).
A 2019 study published in February looked more closely at placental lesions and their relationships with HIE. The study looked at the records of 67 newborns with HIE between 2006 and 2014 (2). All of these newborns matched a control group without HIE for gestational age, birth year, weight, and gender.
The pathologist was able to acquire archived placental findings for 46 of the newborns with HIE. These placental findings were matched with 92 placental findings from the control group.It was discovered that the placentas of the newborns with HIE had more fetal vascular malperfusion, which refers to vascular flow abnormalities on the fetal side of the placenta (3). They also had more maternal vascular malperfusion, which refers to vascular flow abnormalities on the maternal side of the placenta. Finally, they had more clinical abruption instances than the control group (2).
The controls in the study were found to have more normal placental findings and more cases of chorioamnionitis than the newborns with HIE.
Each of these placental findings is referred to as a pre-specified placental lesion. Moreover, pre-specified placental lesions occurred in 87% of the newborns with HIE and only 65% of the controls (2).
The study concluded that there is an association between these pre-specified placental lesions and instances of HIE.
- Nasiell, J. (2015, February 25). Hypoxic ischemic encephalopathy in newborns linked to placental and umbilical cord abnormalities. Retrieved March 29, 2019, from https://www.tandfonline.com/doi/abs/10.3109/14767058.2015.1015984?journalCode=ijmf20
- Bingham, A., Gundogan, F., Rand, K., & Laptook, A. R. (2019, February 15). Placental findings among newborns with hypoxic ischemic encephalopathy. Retrieved March 29, 2019, from https://www.nature.com/articles/s41372-019-0334-9
- Roberts, D. J. (2019, February 7). The placental pathology report. Retrieved March 29, 2019, from https://www.uptodate.com/contents/the-placental-pathology-report