How To Understand a Fetal Monitor

Unless you have an extremely fast birth, you can expect to be put on a fetal monitor at some point during your birth, perhaps during your whole birth.  A fetal monitor is exactly what it sounds like-it monitors your baby's heartbeat.  While a few hospitals continue to use portable Doppler units (like what your ob/gyn or midwife uses during your prenatal appointments), the majority of hospitals use a fetal monitor.  Physicians like to monitor your baby's heartbeat because some variations may indicate a problem, though the majority of variations are perfectly normal.

  1. A fetal monitor measures your baby's heartbeat by connecting via wires to a disc on the outside of your belly, also called an external monitor (number 4) or connecting directly to your baby through your vagina, called an internal monitor (number 5).  The machine prints out a strip of paper that shows your baby's heartbeat (look for a long line).  The machine is also hooked up to a computer screen and to the nurse's station.  So if your nurse isn't in the room with you, don't worry; she or another nurse can still be watching your baby's heartbeat from the nurses' station.    
  2. Your nurse, midwife or ob/gyn is the best person to help you understand a fetal monitor and the variation in your baby's heartbeat that occurs during labor.   Feel free to ask questions about your baby's heartbeat as your labor continues. A layperson such as your partner, family member, or doula cannot read a fetal monitor and should not provide interpretations unless they have had special training.  As such, this article is meant to give basic information about fetal monitors, not teach you how to read one.
  3. A normal baby's heartbeat is between 120-160 beats per minute.  It is normal for there to be variation in your baby's heartbeat.  In fact, your physician will prefer it.  Your baby's heartbeat should go up and down to some degree during your labor.  This indicates your baby is moving around, just as she has during the majority of your pregnancy.  In addition, it is normal for your baby's heartbeat to change during contractions.  During transition contractions and pushing contractions, your baby's heartbeat may actually drop.  This is normal and nothing to be concerned about, as long as your baby's heartbeat goes up back up again after the contraction is complete.   If your baby's heartbeat does not go back up, or goes up slowly, your doctor may be concerned and will discuss the next course of action with you.   
  4. An external fetal monitor is the round disc that goes onto your belly and is held in place by a belt or a girdle.  This disc is an ultrasound device that senses and receives sound waves in order to get an accurate count of your baby's heartbeat.  The disc is connected to a fetal monitor machine via a wire.  This device is fairly accurate, but not as accurate as an internal monitor (see below).  Another drawback is that many laboring women find it difficult to find a comfortable position due to the wires running from their bellies to the machines.  In addition, if the disc slips or your baby moves, the monitor will have to be repositioned and this can be frustrating to the laboring woman. 
  5. An internal fetal monitor is placed into the vagina and screwed into the skin on your baby's head.  It sounds harsher than it is, and only makes a very small prick in your baby's skin. An internal monitor is more accurate than an external monitor and is usually used if your care provider feels a problem is developing or your care provider cannot get an accurate reading with the external monitor.  Many care providers will allow you to get out of bed and find comfortable positions for labor with an internal monitor in place, but not all.  Another drawback is that your bag of water must be ruptured for an internal monitor to be placed.  This increases the risk of infection, especially if your labor is a long one.  Many care providers will not allow you to labor past sixteen to twenty-four hours (depending on the care provider) after your membranes are ruptured.  The final drawback is the risk of infection at the site the internal monitor is placed in your baby's head.


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