Home / Guides / Medical care

What fetal heart rate monitoring is and why it is often used near the end of pregnancy

NNova editorial team · 5 min read

Fetal heart rate monitoring, often called an NST or EFM, checks the baby's heartbeat and how it changes with movement and contractions. How often it is done depends on the pregnancy week, baby movements, health conditions, and earlier results.

What fetal monitoring shows

Fetal monitoring uses two sensors on the belly to record the baby's heart rate and the timing of uterine contractions. The provider looks at how the heart rate changes with the baby's movements and contractions, along with the rest of the pregnancy picture.

Why it is often used near the end

  • As the baby grows, providers may check how the heart rate responds to movement and contractions.
  • Starting around 32 to 34 weeks, or earlier for some high-risk pregnancies, providers may use monitoring to check on the baby's well-being.
  • Monitoring is often more frequent if the baby moves less, if blood pressure is high, if diabetes is present, if the amniotic fluid level is low, or if the pregnancy goes past the due date.
  • During labor, monitoring helps providers notice changes in the heart rate early.
A monitoring result is not a diagnosis on its own. Providers interpret it together with the pregnancy week, the baby's movements, the physical exam, and other test results.

When a result may need more attention

Findings that may need follow-up include a heart rate pattern that stays abnormal for a long time, low variability (the heart rate changes very little), repeated decelerations (drops in heart rate), or these results along with fewer movements. Sometimes the cause is temporary, such as the baby sleeping, the baby's position, or certain medicines. Your provider will explain what a result means for you.

When to call your provider

  • You notice fewer movements than usual. Many providers suggest counting kicks each day and calling right away if you count fewer than 10 movements in 2 hours.
  • You have bleeding, fluid leaking from the vagina, severe belly pain, severe headache, vision changes, or sudden swelling of the face or hands.
  • You have any concern about your baby, even if you are not sure it is serious.

Fetal monitoring is painless and does not involve needles or entering the body. It helps providers make careful decisions about care, especially as the due date gets closer.

Learn more

Follow your pregnancy in Nova

Week-by-week growth, a symptom log and a report for your doctor.

Get it on the App Store

General information only; it does not replace advice from your doctor or midwife.