Fetal Monitors in Labor: Pros and Cons

Fetal Monitors in Labor - Pros and Cons - Image

Whether you labor and deliver in a hospital or at home, your healthcare provider will monitor your baby throughout labor. Monitoring can take several forms, and it’s helpful to understand them each ahead of time. So let’s dive into the types of fetal monitors and the pros and cons of fetal monitors in labor.

Estimated reading time: 7 minutes

Fetal Monitors In Labor: Why?

Fetal monitors, as the name suggests, monitor the fetus. Basically, they’re a way for your doctor or midwife to keep an eye on your baby’s wellbeing during labor. They do this by watching how your baby’s heart rate reacts to contractions. The normal pattern is for baby to have a “reactive” heart rate. This means that the heart rate slows down a bit during contractions to compensate for temporarily reduced oxygen, and then speeds up again between contractions (1). When doctors see this pattern, they feel more confident that baby is handling labor well and working with the changes in oxygen flow that naturally happen during contractions.

External Fetal Monitors in Labor

External fetal monitors are the most common type of monitors you will use during your pregnancy. They’re simple, noninvasive, and can be used at any point during labor — before or after your water breaks. Here’s the equipment you’d expect to see if you have electronic external fetal monitoring during labor.

External Fetal Monitors

Cardiotocograph (CTG) Machine

The nurse will place two flexible straps across your abdomen, and each holds a small device with wires that connect to the CTG machine. The machine gives a printed readout of two key pieces of data — the heart rate and contractions — shown together, which is called the EFM tracings. In addition to the paper readout from the machine, the EFM tracings may also be seen at the nurses’ station and possibly on the doctor’s computer, as well.


The ultrasound device is one of the two recording devices that feed information to the CTG machine. The ultrasound device, placed low on the abdomen, monitors the baby’s heartbeat.


The tocodyamometer, placed high on the abdomen, gauges the frequency and duration of a contraction. Despite what many people think, the tocodynamometer can’t tell you how strong the contraction is, but rather just that you’re having one.

Internal Fetal Monitors in Labor

Internal fetal monitors are used assess the same information as external monitors, but they are placed up through the vagina and inside the uterus instead of strapped to the abdomen. They also add the ability to see the strength of contractions. Internal monitors are only an option after your membranes have ruptured (also referred to as your water breaking), because they need to be placed directly on the baby. Internal fetal monitoring may be suggested if the external monitors aren’t picking up signals well enough or if there is concern that the baby may be showing signs of distress.

Although it can be necessary at times, internal fetal monitoring is the most invasive form of monitoring. Mom must remain in bed, and she’s unable to move freely or change position very much. But it can provide useful information in high-risk scenarios. Here’s the equipment you’d expect to see if you have electronic internal fetal monitors in labor.

Internal Fetal Monitors in Labor - Image
Internal Fetal Monitors

Fetal Electrode

The fetal electrode (also called fetal scalp electrode or FSE) is a small wire electrode that your doctor puts through your vagina, through the cervix, and attaches directly to baby’s scalp or other presenting part. (Don’t worry, this doesn’t cause any pain. It’s similar to the electrodes that are placed on your chest if you’ve ever had an EKG.) It records the baby’s heart rate.

Intrauterine Pressure Catheter

This is also placed up through the cervix and into the uterus. It assesses the frequency and duration of contractions, as well as the intensity of the contraction.

Pros and Cons of External Fetal Monitors


  • Less invasive than internal monitors.
  • The amniotic sac does not have to be ruptured.
  • Poses little risk to mom or baby, and you can have it removed at any time.
  • Allow mom to assume a variety of positions, though they do limit her ability to take a walk or move very far because of the wires that attach to a nearby computer.
  • Some facilities offer wireless, belt-free external fetal monitoring called telemetry, which allows mom to move freely.


  • Less accurate than internal monitors (3).
  • May restrict mom’s movement since they require cords attached to a computer.
  • Signal from the units can be easily disrupted if baby or mom are moving around a lot.  
  • May accidentally detect mom’s heart rate.
  • Often not effective in obese mothers (3), because they’re unable to measure the tension of the uterus through the skin as easily.

Pros and Cons of Internal Fetal Monitors:


  • Provide continuous information about baby’s heart rate. As baby wiggles and moves, the heart rate tracing will not get lost.
  • Provide accurate information about the intensity of contractions. This can be helpful during a pitocin induction to help the provider gauge the intensity of the contractions, to be sure they’re not too strong.


  • Internal fetal monitors in labor are invasive.  
  • After they’re placed, mom is virtually unable to move because movement could tug out the monitors.
  • Require rupture of the amniotic sac, as well as some cervical dilation.  
  • Come with a risk of infection and possibly some harm to the baby.  

Auscultation – The Best Option?

Auscultation is when the provider periodically listens to the baby’s heartbeat without the use of electronic fetal monitoring. This means that while the doctor or midwife is still monitoring baby, but it’s intermittent (or every so often) instead of constant monitoring. This can be done using a fetoscope, a special type of stethoscope, or through a handheld Doppler unit.

Studies show that there is no significant difference in outcomes between external electronic fetal monitoring and auscultation (4); in other words, babies aren’t more likely to face poor outcomes if they’re not constantly monitored. In fact, external fetal monitoring leads to cesarean and assisted deliveries more often than intermittent monitoring. Thus, for women without complications, intermittent auscultation is considered the safest form of fetal monitoring (5).

Speaking Up

Despite the fact that studies show auscultation to be safe–and in fact, the safest form of fetal monitoring)–many facilities routinely use external monitoring on all laboring women. There are many reasons why this may be true. It may be for the convenience of the caregivers — it takes less time to hook you up once than to repeatedly check your stats, and it’s convenient to have a readout of multiple patients visible to nurses at the nurses’ station at all times. It also may be that caregivers have their own opinions about what method is safest.

Communication is Key

Either way, it’s a good idea for you to talk to your doctor or midwife about it ahead of time. Ask what type of monitoring they use for low-risk labors, and ask in what scenarios they consider it necessary to escalate to a higher level of monitoring. Talk to your caregiver about your preferences. Know that you have the right to speak up and help make decisions in your own care.

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  1. Simkin, P., Whalley, J., Keppler, A., Durham, J., & Bolding, A. (2016). Pregnancy, Childbirth, and the Newborn: The Complete Guide. Minnetonka: Meadowbrook Press.
  2. Glade, B.C., Schuler, J.  (2011).  Your Pregnancy Week by Week, 7th edition.  First Da Capo Press
  3. Jain, S., F. Saad, A., & S. Basraon, S. (2016). Comparing uterine ELECTROMYOGRAPHY & Tocodynamometer TO Intrauterine PRESSURE Catheter for Monitoring Labor. Journal of Woman’s Reproductive Health, 1(3), 22-30. doi:10.14302/issn.2381-862x.jwrh-15-771
  4. Wood S. H. (2003). Should women be given a choice about fetal assessment in labor?. MCN. The American journal of maternal child nursing28(5), 292–300. https://doi.org/10.1097/00005721-200309000-00004
  5. ACOG Practice Bulletin No. 106: Intrapartum fetal heart rate monitoring: nomenclature, interpretation, and general management principles. (2009). Obstetrics and gynecology114(1), 192–202. https://doi.org/10.1097/AOG.0b013e3181aef106

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Meet Katie Griffin

I’m a registered nurse, Lamaze certified childbirth educator, and the mother of 7. I help women realize their dream of a natural, intimate, and empowering hospital birth.

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Whether you labor and deliver in a hospital or at home, your healthcare provider will monitor your baby throughout labor. Monitoring can take several forms, and it’s helpful to understand