By Mathew Miller, Sharon Perkins

Fetal monitoring devices record the fetal heart rate and the frequency and duration of the contractions. Sounds cool, right? Here’s a Dad’s guide. Just don’t let yourself become so enamored with the technology that you forget about the person at the other end!

Many men love gadgets and start watching the monitor like it’s the educational channel, but it is guaranteed that if you do that, your partner won’t appreciate it.

How to monitor your partner and the baby externally

External monitoring systems consist of two recording devices fastened around your partner’s stomach and plugged into a fetal monitor, which provides a continuous printout of the fetal heart rate and the contractions. The monitor records the duration of contractions and the time between them but doesn’t tell you the strength of the contraction.

Each contraction resembles a hill or a bell-shaped curve, starting low, rising slowly, and then returning to baseline. Because the device sits on your partner’s abdomen, attached with a belt, her body shape and position can affect how the contractions look on the monitor. Contractions that look like very large mountains on the monitor don’t always indicate really strong contractions, and tiny hills don’t necessarily mean the contractions are mild.

The external fetal heart monitor tracks and records the fetal heart rate as well, but it has some limitations. Namely, it records an average of beats rather than the baby’s exact heartbeat. External monitors can’t determine variability, the difference in heart rate over a certain time period, and beat-to-beat variability can help ascertain how well the baby is handling labor.

A heartbeat that stays the same with little variation may indicate that the baby is stressed. Short periods of decreased variability also occur when the baby is asleep. (And yes, babies do take short naps during labor!) The fetal heart rate may also have a short period of minimal beat-to-beat variability if your partner gets a dose of a narcotic pain medication.

The external monitor also can’t always distinguish between mom’s heart rate and baby’s. If your partner has a rapid heartbeat because of fever, anxiety, or other reasons, or if the baby has bradycardia (an extremely low heart rate), it may not be obvious that the external monitor isn’t recording the right heartbeat.

Basics of internal monitors for Dads

Internal monitors resolve the shortcomings of external monitors by giving more accurate information. Internal contraction monitors are inserted directly into the uterus, which makes them able to record the exact strength of each contraction.

You may be disappointed to watch those huge mountains that appeared to be very strong contractions shrink down to little blips on the monitor, indicating that the uterus is contracting only mildly, or you may be excited to see the opposite.

Internal fetal monitors fasten a tiny wire into the baby’s scalp that records the exact fetal heart rate. This ensures that the variability displayed is an accurate representation of the fetal heartbeat. An internal monitor can also differentiate maternal and fetal heart rates, if it’s difficult to tell whose heart rate is recording on the external monitor.

Some centers use internal monitors routinely, whereas others use them only if they’re having trouble picking up the heart rate or assessing the contractions. Internal monitor complications occur rarely and include infection at the site of insertion or hematoma (a large bruise).