When the FDA isn't busy rebutting the health claims of Cheerios, it sounds like these days they have their hands full with medical device approvals for modern enhancements to continuous electronic fetal monitoring (EFM). One supposedly 'noninvasive' device in the approval pipeline features 32 electrodes attached to the mother's abdomen that measure beat-to-beat fetal heart rate variability in pregnancies as early as 20 weeks. Another that has already received the green light from the FDA allows obstetricians to view real-time EFM data on their iPhones. And let's not forget the comical-if-it-weren't-so-barbaric 'BirthTrack,' an FDA-approved technology that continuously monitors cervical dilation and fetal descent in combination with fetal heart rate.

These are just a few of the latest examples of attempts to improve upon EFM, a technology that is used in 94% of labors despite evidence that it increases the chance of a cesarean or instrumental vaginal birth but does not prevent serious or long-term problems in babies. In 2006, researchers declared that measuring fetal oxygen saturation along with continuous fetal monitoring was a worthless enhancement. Confirming EFM findings by testing the acidity of a sample of the baby's blood is another once-promising approach that is unreliable and has fallen out of favor.

OK, so tweaking the technology doesn't solve the problem. Maybe the problem is that the professionals charged with interpreting EFM data need better training or can't communicate effectively? This is the theory behind the latest NICHD Guidelines for interpreting EFM, and countless hospital-based patient safety programs. But even after NICHD's last attempt at standardizing EFM interpretation, experienced maternal-fetal medicine specialists could not agree about the significance of worrisome EFM patterns, or which tracings warranted immediate cesarean surgery to prevent poor outcomes.

So why have we not seen any meaningful improvements in maternal and newborn outcomes even with electronic fetal monitoring done earlier in pregnancy, with more bells and whistles, and with countless federal and hospital dollars spent training health care workers in its use?

Perhaps it is the underlying premise itself that we must reassess. Maybe fetal heart rate isn't such a great predictor of fetal wellbeing after all. Sure, at the extremes it can tell us which babies are in serious trouble and which are sailing through labor with no trouble at all. But anywhere between these extremes is much murkier territory. Many babies will be born pink and screaming despite worrisome heart rate patterns, but a few will be compromised and need resuscitation, ongoing observation, or other measures. And even when fetal heart rate does predict the babies who will be compromised at birth, most of these babies will not suffer any serious or long-term consequences. So fetal heart rate doesn't predict outcome at birth very well, and poor outcome at birth doesn't predict long-term morbidity very well. How can we then expect the fetal heart rate to possibly predict or affect long-term outcome well?

Instead of the futile and costly effort to improve upon EFM, we should spend those resources providing, evaluating, and improving intermittent auscultation, the low-tech, low-risk alternative that has proven safe and effective in healthy women. Not only is intermittent auscultation safe for the vast majority of babies, it facilitates the other practices we know contribute to safe and healthy birth - continuous labor support, freedom of movement, and upright pushing positions, to name just a few.

Published: June 04, 2009

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