Fetal heart rate monitoring, and what happens when it is not acted on

What is it?

Two sensors sit on the abdomen. One records the baby's heart rate. The other records contractions. Together they produce a strip with two lines: the baby's heart rate on top, contractions underneath.

Sometimes a small electrode is placed on the baby's scalp for a more reliable heart rate signal, or a catheter is placed inside the uterus to measure contraction strength directly.

Four features of the heart rate are read. ²

Baseline rate. The average heart rate over 10 minutes, normally between 110 and 160 beats per minute. ¹

variability. The small moment-to-moment fluctuations. Moderate variability is a reassuring feature and is strongly associated with the absence of significant acid build-up at the time it is seen. ¹

Accelerations. Brief increases in heart rate, generally a good sign.

Decelerations. Decreases in heart rate, and their shape and timing relative to contractions is what matters.

• Early decelerations mirror the contraction and are caused by head compression. They are not concerning.
• Variable decelerations are abrupt drops, usually from cord compression. Their significance depends on depth, duration and how they recover.
• Late decelerations begin after the contraction starts and return to baseline after it ends. Repeated late decelerations suggest the placenta is not delivering enough oxygen during contractions. ¹
• Prolonged decelerations last two minutes or more and require immediate assessment.

What does standard care look like?

The three-category system defines what each pattern calls for. ^{1 2}

Category I. Normal. Normal baseline, moderate variability, no late or variable decelerations. Routine monitoring continues.

Category II. Everything that is not Category I and not Category III. This is by far the largest group. It includes many tracings that are fine and some that are not. Guidance says Category II calls for evaluation, continued watching, and reassessment. The whole clinical picture is taken into account. It is not a category to record and move past. ¹

Category III. Absent variability with recurrent late decelerations. Or absent variability with recurrent variable decelerations. Or absent variability with a slow heart rate. Or a sinusoidal pattern. Guidance calls this abnormal. It is linked to abnormal acid levels in the baby. It calls for prompt evaluation and action. ¹

What action means

Guidance describes a set of measures for a concerning tracing. ⁵ They include changing position. Giving intravenous fluid. Giving oxygen. Stopping or reducing oxytocin. Treating low blood pressure. Considering medication to relax the uterus. If these do not resolve the pattern, delivery is considered.

What the record should contain

The strip itself, timed. Nursing notes recording what was seen and what was done. Notes of when the physician was informed and what their response was. The time of any decision to deliver, and the time of delivery.

What can go wrong?

Several patterns recur when families read their own records.

The tracing was concerning and nothing changed. Category II tracings call for evaluation and reassessment. Sometimes a record shows a concerning tracing for a long stretch. No assessment is written down. No action is recorded. That is a gap between what happened and what guidance describes. ¹

Nobody was told, or nobody came. Nursing notes may record escalation to a physician that produced no documented response, or no escalation at all.

Loss of variability was not recognized. Loss of moderate variability together with recurrent decelerations is the combination that defines Category III. ¹

The monitor was not recording. Long stretches of unreadable or absent tracing during a period when the baby was being watched are a genuine problem, because there is no record of what was happening.

oxytocin continued despite a concerning pattern. Reducing or stopping oxytocin is one of the standard responses. ⁵

tachysystole not recognized. More than five contractions in 10 minutes averaged over 30 minutes leaves the placenta less time to refill with oxygenated blood between contractions. ¹

A decision to deliver was made and the delivery was slow. The interval between the decision and the birth is recorded, and it is one of the first things a reviewer looks at. ⁶

None of these, on their own, establishes that anything caused an injury. Professional guidance is explicit that no single finding establishes that events during labor caused newborn brain injury, and that cause is worked out from a pattern of findings taken together. ⁴

Which injuries can follow?

Where a baby's oxygen supply is significantly reduced during labor and it is not relieved, the injuries associated with it are:

• Hypoxic-ischemic encephalopathy, which is brain injury from low oxygen and low blood flow. ⁴
• Neonatal seizures in the first days. ⁷
• Cerebral palsy, where brain injury is significant, though most cerebral palsy is not caused by events during labor. ⁴
• Meconium aspiration syndrome, where a stressed baby passes and inhales meconium.
• Persistent pulmonary hypertension. ⁸
• Hearing loss and cortical visual impairment after significant brain injury. ⁹

A concerning tracing does not mean a baby was injured. Most babies with Category II tracings, and many with Category III tracings, are born well. What the tracing does is record what was known at the time and what the team could see.

What does this look like in the records?

This is the section to bring to a records request.

Ask for the fetal monitoring strips themselves, not a summary. They may be on paper or stored digitally, and digital archives are often kept separately from the main chart. Say explicitly that you want the complete continuous tracing for the entire labor. ¹⁰

What to look for on the strip

• The baseline rate over time, and whether it rose or fell.
• Whether variability was present, reduced or absent, and when that changed.
• The type, depth and frequency of decelerations.
• Contraction frequency, counted over 10 minutes, and whether tachysystole occurred.
• Gaps in the recording.

What to look for in the notes alongside it

• Nursing entries describing what was seen and what was done.
• The time each intervention was performed: position change, fluids, oxygen, stopping oxytocin.
• The time a physician was notified, and by what method.
• The time the physician assessed the patient.
• The time a decision to deliver was made.
• The time of delivery.
• The oxytocin infusion record, showing the rate and each change with its time.

Alongside the strip

• The cord blood gas results. ⁴
• The Apgar score scores at 1, 5 and 10 minutes. ¹¹
• The newborn resuscitation record. ¹²
• The placental pathology report, which is often filed separately.

The reading your records guide explains each of these documents in detail, and the records request builder writes the request letter for you.

What can you do this week?

1. Request the complete labor and delivery record for you and your baby. The records request builder writes the letters for you.
2. Write down what you remember while it is fresh, using the delivery timeline builder.
3. Read how to read your labor and delivery records before the records arrive.
4. Check the deadline to file in your state with the statute of limitations lookup.