Heart to Hart - Listening in Labor

Heart to Hart is a recurring column in SQUAT, one of of our very favorite features each issue. Lo Kawulok, a midwife in Colorado, poses some questions to seasoned midwife Gail Hart, who answers with evidence and experience. As Lo wrote in SQUAT: "The best part about backing up what we know to be true about birth is that the intuitive and scientific pieces profoundly resonate."

In SQUAT's last issue, Lo asked Gail about monitoring fetal heart tones during later. The whole issue can be purchased here. If you don't already "like" SQUAT on Facebook, please do! We'll be releasing the digital version of this issue for free when we reach 2,000 "likes"!

Listening in Labor

During labor, listening to fetal heart tones can give us an idea as to how baby is reacting to the immense environmental changes that take place throughout the birthing process. Fetal heart tones normally change due to a response to contractions; these changes then may start to form a pattern which can illustrate many things such as a happy, healthy baby, or a baby who needs help.

As birth workers, we are usually educated on the techniques used to listen and record these patterns, as well as how to interpret and resolve possible complications. This, however, can vary widely, depending on with whom and where the birth is taking place such as a hospital, birth center, or home.

In the case of a healthy, low risk mama in active labor, why do these guidelines vary so much? How can one protocol call for constant monitoring (electronic fetal monitoring in the hospital), while another may require intermittent monitoring every five to ten minutes (typical out of hospital standard)? We want to know Gail, hospital and state-specific regulations aside, what is the evidence telling us to be the safest and most comprehensive manner to observe a baby's heartbeat in labor? What does your protocol look like?

Knowledge is Power!
Lo Kawulok


From Gail....

"Protocols" are guidelines and recommendations created by groups, agencies, associations or research institutions. They are written to educate caregivers in the best practices for their profession. But these guidelines and recommendations are not necessarily based upon good evidence; they may be heavily weighted by opinion, or may be influenced by outside professions. (Malpractice attorneys have a prominent voice in many current recommendations.) A midwife must be aware of protocols and be able to evaluate the source and the application to her particular practice or clients. Although "protocols" are intended to be individually-applied recommendations, some licensed midwives are under the authority of licensing agencies which have made these legal requirements. Unfortunately, some licensing agencies are misinformed about correct recommendations and may mandate protocols for fetal assessment in labor which are not appropriate for out of hospital midwives (OOH). This forces the licensed midwife to chose between her licensing rules and different recommendations which are better tailored for OOH clients.

It is essential to be aware of the baby's condition in the womb! Listening to the baby's heartbeat at regular intervals is an effective method to quickly check on how he/she is tolerating the stresses of labor. Make no mistake about this: labor is a stressful condition and some babies can be harmed by diminished blood-flow or poor oxygenation. Uterine contractions slow the placental circulation and the exchange of oxygenated blood to the baby. Some babies may have cords which are pinched or knotted. A healthy baby can compensate for a period of time, but not all babies are healthy. As the length of labor continues, the baby will become less oxygenated and may develop acidosis. His heart rate will change in response to these stresses and we will know he is in trouble; but only if we are listening-- and paying attention to the heart rate!

There is a wide range of texts on electronic fetal monitoring (EFM) and using subtle signs in the heart rate to detect fetal distress in labor. The terminology, definitions, and theories change with new editions as various experts battle about the significance of tiny variations in heart rate pattern. New electronic fetal monitoring gadgets come on the market and are soon replaced by “the next new thing” which is supposed to provide faster and better detection without the high error rate of the previous gadget. The “high error rate” is a huge problem with all of the electronic fetal monitoring devices. The marketing of EFM machinery was more rapid than the science to support it. The science – the evidence – shows that EFM machines do not reduce the rate of birth complications or stillbirth when compared with listening to the baby at regular intervals (intermittent auscultation). Rather, EFM results in a large number of unnecessary emergency cesarean sections to rescue healthy babies which were assumed to be in danger of asphyxia. Listening to the baby at regular intervals is a better option for monitoring low risk women and is the actual recommendation of ACOG, the US Preventive Health Services Taskforce and many other obstetrics organizations. (1)

The human ear – and the mother – are the most accurate detectors of the baby's condition in labor. A healthy baby moves, kicks, and wriggles--even during labor. A baby who is moving gives us reassurance that he is likely handling labor without problems (it is a good idea to include notes about fetal movements on your labor charts). Babies are usually quieter in labor, but they still move and mothers can feel this – and you as the midwife can see this.

But to really know how the baby is doing we must listen to the heart beating – listening frequently but, even more importantly, we need to listen long enough to know the pattern. This means listening for the full length of contractions rather than the quick counts which are commonly done (and commonly taught).

The basic human physiology of a baby in labor is the same now as it was centuries ago and these facts are not affected by ever-changing protocols or electronic gadgetry. All the EFM machines in the world can not improve upon the generation's old understanding of the baby's heartbeat in labor. Every birth worker must know these basic facts of fetal heart patterns.

• The average resting fetal heart rate is 120 to 160, and the rate accelerates for a short period in response to fetal movements. The acceleration returns to the basic resting rate within 15 to 30 seconds.
• A normal fetal heart rate may slow during a uterine contraction but usually recovers to the normal rate shortly after the contraction.
• A slow fetal heart rate in the absence of contractions or which remains slow after the end of the contraction suggests fetal distress; if it does not rise to the normal rate within 30 seconds it strongly suggests fetal distress.
• A rapid resting fetal heart rate may be a response to maternal fever, drugs which cause a rapid maternal heart rate, hypertension (high blood pressure), or amnionitis (uterine infection). If the mother's heart rate is normal, a rapid fetal heart rate should be considered a sign of fetal distress

How often should we listen to the baby?

I think the American College of Obstetricians and Gynecologists (ACOG) has a reasonable guideline. ACOG recommends listening to the heart rate “every 30 minutes during active labor, and every fifteen minutes during second stage. The heart should be listened to through the contraction and for at least 30 seconds after the contraction ends”. (2) This schedule nicely balances the need to monitor with the mother's need for privacy. Some licensing agencies require midwives to listen every fifteen minutes in active labor, and every five minutes during second stage! Such frequent interruptions may disturb the mother and interrupt the labor pattern. It is important that we listen to the baby, but we should try to avoid disrupting the mother's concentration. To my mind, a fifteen minute schedule for second stage feels about right.

I modify this schedule to fit the individual mother and baby. I listen more frequently if the membranes are ruptured because the pressure on the baby is greater after he loses the protection of the amniotic fluid. If I am present when the water breaks, I listen continuously for five minutes to make sure there's no problem with the cord. Then I listen again every five minutes for the next fifteen minutes to see how the baby is reacting to the change in pressure. I listen more frequently if the labor is prolonged, or the baby's position is unusual, or if there is meconium in the amniotic fluid.

photo: LA Times

If the mother's active labor is intermittent with a lot of resting periods, I will listen less often. If the mother is not having strong frequent contractions, then her baby is obviously not experiencing stresses from labor. I'm not going to wake a woman from a sound sleep just to listen to her baby! If contractions are mild, the pressure is mild also and the baby has little stress. But if the contractions are strong and long, the pressure is greater and we need to listen more frequently to make sure the baby handles the increased stress.

Protocols and guidelines can give us a rough schedule to follow, but the woman and her baby are individuals. My role of midwife in her birth will have to adapt to her individual requirements. I will listen to the baby with my ears, but with my other senses and intuition also. Almost always labor goes well, and our checking on the baby's heart rate just gives the mother additional reassurance that all is still well.

(1)Macones GA, Hankins GDV, Spong CY, Hauth J, Moore T. The 2008 National Institute of Child Health and Human Development workshop report on electronic fetal monitoring: update on definitions, interpretation, and research guidelines. Obstet Gynecol. 2008;112:661–666.

(2)American College of Obstetricians and Gynecologists, American College of Obstetricians and Gynecologists."ACOG Practice Bulletin Number 106: Intrapartum fetal heart rate monitoring: nomenclature, interpretation, and general management principles" Obstet Gynecol 2009; 114: 192-202.