Late Decelerations: All You Need to Know

What are late decelerations, and what causes them? We’ll take you through why they happen and what they mean for you and your baby.
Monitoring your baby’s heartbeat is an important part of your antenatal care right up to the end of your pregnancy.

When you are in labor, one of the things your healthcare providers will be looking out for is late decelerations.

We’ll take you through what that means.

In this article: 📝

What are decelerations?
What is the difference between early and late decelerations?
What do late decelerations indicate?
What causes late decelerations in a fetus?
Are late decelerations an emergency?
How do healthcare providers monitor fetal heart rate?
Late decelerations nursing interventions

What are decelerations?

Decelerations are a temporary slowing down of your baby’s heart rate.

During labor, the muscles of the uterus tighten up and then let go.

These are called contractions.

You may have already felt them during the course of your pregnancy.

Known as Braxton Hicks contractions, these are like a little dress rehearsal for the real deal.

Labor contractions are often more intense and regular.

And one of their many effects can be changes to your baby’s heart rate.

Fluctuations in fetal heart rate during labor are 100% normal.

It’s hard work, after all, for both you and your baby.

But, when they occur in certain patterns, changes like late decelerations can be a sign of fetal distress.

Noting when your baby’s heart speeds up (accelerates), and when it slows down (decelerates), can tell your birth team a lot about how your baby is coping in labor.

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What is the difference between early and late decelerations?

There are actually three kinds of decelerations — early, variable and late.

Early decelerations

Early decelerations are when your baby’s heartbeat slows down right around the time you reach the peak of your contraction.

They are caused by your baby’s head being squeezed during that contraction and are usually nothing to be concerned about.

Variable decelerations

Variable decelerations are big, irregular dips in the fetal heart rate.

They are often more pronounced than other types of decelerations, and will be closely watched by your birth team.

They can be normal and nothing to worry about, but in some cases, may signal that something’s up.

They can be caused by the umbilical cord being compressed for a brief period.

This can be concerning because it may signal a problem with your baby’s blood flow or oxygen supply.

Your healthcare providers will look at the whole picture of your pregnancy and labor before deciding if any sort of intervention is necessary.

In some cases, they may recommend a c-section if you are giving birth vaginally.

But in others, they’ll just need to monitor the situation closely.

Late decelerations

These happen when your baby’s heartbeat slows down after the peak of your contraction, instead of at the same time.

They are literally “late” and need close attention by your doctor or midwife.

What do late decelerations indicate?

Maybe nothing at all. It’s not always a sign of anything serious.

Sometimes they just happen.

Either way, you can rest assured your birth team will keep a close eye on them to be certain.

So when are they cause for concern?

Late deceleration can mean decreased blood flow to the placenta.

That means that baby gets less blood and oxygen — a condition known as uteroplacental insufficiency.

What causes late decelerations in a fetus?

There are several possible causes for this.

Sometimes, it happens from normal labor-related activities, like pushing.

It can also be a sign of dehydration, where your fluids are low, or anemia, where red blood cells are in short supply.

It might also be caused by hypotension (low blood pressure) from having an epidural.

Whatever is at the root of it, it usually signals something called hypoxia, where your baby has low oxygen levels in your blood.

And although this may sound scary, it’s actually a normal feature of labor.

The contractions, that are part and parcel of labor, also compress blood vessels.

In some cases, late decelerations can be more concerning. Here are some possibilities:

Uterine tachysystole, or very frequent contractions. This can become [risky for your baby]9https://pubmed.ncbi.nlm.nih.gov/22901710/) when there are more than five contractions in ten minutes over a 30-minute window.
Placental abruption, which is a very serious condition where the placenta separates from the uterus before the baby is born.
Nuchal cord, where the umbilical cord is wrapped around the baby’s neck.

Are late decelerations an emergency?

Not necessarily, but they do warrant careful monitoring and extra care in labor.

One late deceleration is not necessarily dangerous, but several could signal a problem.

If they are concerned, your healthcare providers will immediately take steps to ease any underlying causes.

They’ll also note whether the decelerations are consistent and if there are any accelerations or not.

If the late decelerations continue and show no improvement with treatments, complications for your baby can be serious.

We know. This all sounds terrifying. But remember that your team will be on the lookout for these late decelerations.

They will quickly treat the root causes and/or will speed up the process of bringing baby earthside, if necessary.

The good news is, as this recent study explains, the outcomes for babies treated promptly are excellent.

How do healthcare providers monitor fetal heart rate?

Fetal heart rate monitoring is done in two ways:

Auscultation, where the heart beat is checked periodically through using a handheld device, or
Continuous fetal monitoring, which is ongoing electronic monitoring during labor

During a home birth, your midwife will likely use a fetal Doppler to monitor your baby’s heart.

This is a sophisticated device that is even waterproof — useful info if you should find yourself in a birthing pool.

If you are having a hospital birth, your team may use an electronic fetal heart rate monitor to detect your baby’s heart rate, as well as track your contractions.

And sometimes an internal gadget can be applied to your baby’s scalp to give the most accurate heart rate readings.

It’s important that you know that you don’t have to opt for continuous electronic monitoring, unless you need it, as it can cause more distress than necessary. (You’ve already got enough to deal with right now.)

The American College of Obstetricians and Gynecologists (ACOG) has put steps in play to give you the choice of intermittent monitoring, unless continual monitoring is needed.

Late decelerations nursing interventions

The great thing about giving birth in these modern times is that we’ve got more knowledge and tools than ever before to deal with challenges.

If your health care providers do spot late decelerations in labor, they’ll treat you depending on your unique situation. They might:

Turn you on to your left side or into the knee-chest position to reduce pressure on the blood vessels. This will help your baby get better oxygen flow.
Treat low blood pressure, if that’s what you’re struggling with.
Provide you with extra oxygen.

If they were using something like oxytocin — a hormone that causes contractions — to induce or strengthen labor, they may stop this to give your uterus a break.

This is all to get better blood flow to your baby.

Along with being completely awe-inspiring, giving birth can so often feel overwhelming and full of things to worry about.

If you feel like you need a little extra support in this thing called pregnancy, there’s a community rooting for you over at Peanut.