During labor, your healthcare practitioner and nurse will be checking your baby’s heart rate to keep tabs on how he’s doing and see how he’s tolerating your contractions. This is called fetal monitoring. It’s usually done with an electronic fetal monitor or a handheld Doppler device like the one your caregiver used to listen to your baby during your prenatal visits.
Wide, stretchy bands hold two electronic disks called transducers against your abdomen. One monitors your baby’s heartbeat and the other tracks your contractions.
The transducers are connected to a machine near your bed that records this information on paper. You’ll hear the galloping sound of your baby’s heart if the monitor’s volume is turned up.
Your doctor or labor nurse will hold the Doppler or fetoscope against your belly and listen to your baby’s heartbeat, just as she did during prenatal visits, and she’ll assess your contractions by laying her hands on your belly. She’ll check at specific intervals, such as every 15 to 30 minutes in the active phase of the first stage of labor and every five minutes during the second (pushing) stage. She’ll count your baby’s heart rate between contractions when he’s not moving to determine his “baseline” heart rate (normal is between 110 and 160 beats per minute).
That said, if you have a low-risk pregnancy and no complications during labor, the American Congress of Obstetricians and Gynecologists considers intermittent auscultation an acceptable method.
If the external monitor isn’t picking up well (which sometimes happens if you’re moving around a lot or are obese) or your practitioner has some concerns and wants a more accurate reading, she may choose to do internal fetal heart rate monitoring. In this case, an electrode with a tiny spiral wire on the end is inserted through your cervix and screwed into the surface of your baby’s scalp.
Your practitioner may also decide to get more information about the strength of your contractions by inserting a special catheter-like gauge through your cervix for internal uterine monitoring.
Your practitioner will be evaluating your baby’s heart rate frequently throughout labor and watching for anything that could signal a problem. She’ll be looking to see that your baby’s baseline rate is normal and evaluating changes in his heart rate.
But a persistently fast heartbeat can be cause for concern. And while some dips in a baby’s heart rate are normal, others may be worrisome. Sometimes a few simple interventions such as changing your position, giving you more fluids through an IV, and giving you supplemental oxygen may be enough to improve things.
Depending on your situation, other interventions may be necessary, too, which can include stopping oxytocin (Pitocin) if your labor is being induced or augmented; giving you medication to relax your uterus and decrease your contractions; or, if your membranes are ruptured, infusing sterile fluid into your uterus through a slender catheter.
If your baby’s heart rate continues to be questionable or takes a turn for the worse, and your practitioner is uncomfortable letting him stay in the birth canal any longer, you might have an assisted delivery or a c-section.