Determining an Umbilical Cord pH Cutoff Value for Predicting Neonatal Morbidity Related to Intrapartum Hypoxia

Abstract

Intrapartum hypoxia can lead to perinatal asphyxia, acidosis, neuronal injury, long-term morbidity or even death. Intrapartum asphyxia and hypoxia can be predicated by fetal acidosis. Umbilical cord gases are used to evaluate a newborn�s acid-base status and the presence of hypoxia. Depending on what references are used, normal values for umbilical cord gases can wildly vary. Although most papers set a pH threshold of [7.2 for fetal acidosis / acidemia, some studies suggest that neonatal morbidity and mortality is increased only when the pH threshold is set below / cut-off value is 7.0. We did a retrospective study and evaluated all newborns from singleton term births in INSMC Alessandrescu Rusescu between 2010 - 2012. We found 83 cases of intrapartum asphyxia (IA) and 25 cases of hypoxic ischemic encephalopathy (HIE). Also a control group of 100 normal term newborns were randomly selected. The IA and HIE showed significant lower mean umbilical cord pH values compared to the control group (7.19, respectively 7.12 compared to 7.28). Using the Youden index we calculated pH a cutoff value of 7.25 for the prediction of IA and of 7.16 for the prediction of HIE. While a low Apgar score can be a predictor of neonatal outcome and may be determined by fetal hypoxia, it remains a subjective evaluation with variable intra-observer reliability. Thus it is important to have an objective test able to accurately diagnose perinatal asphyxia and predict the neonatal outcome.

Umbilical cord lactate compared with pH as predictors of intrapartum asphyxia

“…We conducted a retrospective, multicenter study to evaluate umbilical cord blood pH and lactate as a mean of evaluating the degree of intrapartum hypoxia and also to establish which of the two is more reliable in predicting morbidity in term neonates. This study continues and extends the research previously carried out by Mogos et al at a single center (7).…”

“…During labor and birth, IA leads to hypoxia and fetal acidosis. Thus, a reliable method for detecting acidosis can be a useful tool for predicting adverse neonatal outcome due to IA (2,(5)(6)(7).…”

“…Acidosis can be evaluated and it is defined as low umbilical cord pH or high umbilical base deficit (expressed as negative base excess, BE) at birth (7)(8)(9). Hypoxia due to impaired blood supply to the fetus leads in the early stages to respiratory acidosis that is characterized by a decrease in pH but normal BE.…”

Inherited thrombophilia is significantly associated with severe preeclampsia

“…Most studies performed on the relationship between thrombophilia and preeclampsia are based on the results of term pregnancies as a control group and complicated pregnancies with preeclampsia treated in tertiary centers as a case group; thus, the results are due to a bias that overestimates the impact of thrombophilia in the group case and underestimates it in the control group. A common result from most studies is the link between thrombophilia and severe preeclampsia to the detriment of the mild one (36,37), a result obtained in the study group as well.…”

Fetal sacrococcygeal immature teratoma – report of two cases and review of the literature

“…From a legal point a view, it is important to explain the prognosis and therapeutic options to the parents and that, despite current advances in pediatric surgery, outcomes are sometimes poor with severe sequelae. Also, when possible, it is recommended to rule out fetal distress during labor and intrapartum asphyxia by documenting umbilical cord gases [34].…”