Fetal Heart Rate Monitoring in Multiple Gestations


LAS VEGAS — In multiple gestations, don't rely solely on the mother's perception of how the fetuses are positioned when monitorig fetal heart rates, Patricia M. Witcher, a registered nurse clinician, advised at a conference on fetal monitoring sponsored by Symposia Medicus.

She acknowledged that sometimes clinicians find themselves doing just that, “especially with women who have been admitted in an inpatient antepartum setting who are due to have quadruplets. She'll say, '[Baby] A is here, B is here, C is here, and D is here.' You can't rely on that.”

An ideal way to identify each fetus before heart rate monitoring would be to use ultrasound, but “that's not realistic because most people who initiate monitoring don't do ultrasound,” said Ms. Witcher, a nurse at Northside Hospital in Atlanta who specializes in labor and delivery and high-risk obstetrics.

The best way to identify each fetus is by doing simultaneous monitoring and looking for divergence of fetal heart rate tracings. “That's really the only way we have of ensuring that we have a heart rate for each fetus,” she said.

She recommends drawing a quadrant on the fetal heart rate tracing that represents the four quadrants of the mother's pelvis. Mark the fetus lowest in the pelvis as “A” and assign subsequent letters to the rest. Using a number system is another option.

“Identification of each fetus is extremely important,” she commented. “I can't tell you how many cases I see where it's not clearly labeled which fetus is which. You can figure it out if you see long-term monitoring, whether there have been interruptions in that segment. You can figure out, 'This baby was in trouble before the mother got up to go to the bathroom, so this must be baby B again,' or whichever baby is having problems.”

In a case of twins, some monitors will print the tracings of fetus A in a dark line and that of fetus B in a light line. Others use different colors of ink to help clinicians differentiate fetuses.

Ms. Witcher added that twins are synchronous in that they tend to exhibit accelerations within 15 seconds of each other in about 51% of cases.

“Synchrony is not an indicator of discordancy,” she said.

“It does not tell you whether you have discordant twins or not. If you don't have synchronous fetal heart rate patterns, it's not any indication that you have a problem with one versus the other. It's just the luck of the draw in timing if you display accelerations at the same time in those babies.”

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