According to a research study completed by the Intermountain Medical Center, fetal heart rate may not be the best indicator of fetal health. In some cases, doctors use fetal heart rates as a deciding factor in pregnancy and birth interventions, including determining whether or not to end labor with a C-section. C-section births are more expensive and lead to increased hospital care, birth costs and risk for birth complications.
Researchers investigated more than 28,000 medical records for the study. The medical records were collected by 10 hospitals operated by Intermountain Medical Center. The fetal heart rates were placed in one of three categories – category 1 for normal heart rates, category 2 for indeterminate and category 3 for abnormal heart rate patterns. In addition to categorizing heart rate patterns, researchers noted how long the fetus' heart rate stayed within a given category.
The study revealed that the majority of fetal heart rates started in category 1 and category 2. During the final two hours of childbirth, however, the numbers changed. More fetal heart rates moved from category 1 to category 2.
After birth, APGAR scores are used to determine infant health. Infants in category 2 at the time of birth were no more likely to suffer reduced APGAR scores than infants in category 1. Most infant health records reported no short-term problems after birth, which means fetal heart rate is not a good indicator of fetal health.
According to Marc Jackson MD, “Our next step, obviously, is to sort out those patterns in Category II to determine which ones are more predictive of a baby that's sick and one that's healthy. When we know that, we will be able to make better decisions for both the mother and her baby.”
Researchers involved in this study are now investigating early deliveries; categorizing fetal heart rate patterns the same way used in this study to determine if the same correlation is evident in pre-term deliveries.
Source: March Jackson MD, et al. Intermountain Medical Center. 28 October, 2011.