Abnormal Nonstress Test Results and Birth Injury Risk: What Parents Need to Know

Receiving news that your nonstress test came back abnormal can be frightening. You may have questions about what the result means for your baby’s health, what happens next, and whether something went wrong. An abnormal nonstress test does not always mean your baby is in danger, but it is a warning signal that requires prompt medical follow-up.

When doctors order a nonstress test, interpret the results, and respond appropriately, most babies with nonreactive results are born healthy. But when medical teams fail to order the test in high-risk pregnancies, misinterpret the findings, or ignore the need for further monitoring, the consequences can include serious birth injuries such as hypoxic-ischemic encephalopathy, stillbirth, or multi-organ damage.

This article explains what a nonstress test is, what reactive and nonreactive results mean, why false positives occur, and what standard medical follow-up looks like. It also outlines how failure to act on an abnormal NST can lead to birth injury and what legal options may be available to families in New York.

What Is a Nonstress Test (NST) and Why Is It Done?

A nonstress test is a noninvasive, painless prenatal test that monitors your baby’s heart rate in response to movement. The test helps assess fetal well-being, placental function, and whether your baby is receiving enough oxygen. During the test, two sensors are placed on your abdomen: one tracks the baby’s heart rate, and the other monitors uterine contractions. You may be asked to press a button when you feel the baby move, or the monitor will record movements automatically.

The term nonstress refers to the fact that no medication or physical stress is applied to the baby during the test. The goal is simply to observe how the baby’s heart rate responds to natural movement.

How the NST Works to Monitor Heart Rate and Movement

In a healthy pregnancy, a baby’s heart rate typically increases when the baby moves. This acceleration is a reassuring sign that the baby’s nervous system is functioning properly and that oxygen levels are adequate. The NST records these accelerations over a period of time, usually twenty minutes, to determine whether the pattern is normal.

If the baby is asleep or in a quieter part of the day, the heart rate may not show the expected accelerations during the initial observation period. In these cases, the test may be extended, or the technician may try gentle stimulation such as sound or a light touch to wake the baby.

When Doctors Order an NST (High-Risk Pregnancies, After 28 Weeks)

Nonstress tests are commonly performed after twenty-eight weeks of gestation, when fetal heart rate patterns are more reliable. According to ACOG, these testing decisions weigh the risk of stillbirth associated with a specific condition against the test’s false-negative rate, which is why testing protocols vary depending on your specific risk factors.

The test may be done once or repeated weekly or more frequently depending on the level of concern. In some cases, an NST is ordered during labor if there are signs of potential fetal distress.

What Does a Normal (Reactive) vs. Abnormal (Nonreactive) NST Mean?

The result of a nonstress test is classified as either reactive or nonreactive. Understanding the difference can help you make sense of what your doctor tells you after the test.

The ’15 by 15′ Rule for a Reactive NST

A reactive NST, which is considered normal, typically shows accelerations of at least fifteen beats per minute above the baby’s baseline heart rate, lasting at least fifteen seconds, occurring at least twice within a twenty-minute window. This pattern is sometimes called the ’15 by 15′ rule, and it applies to babies past 32 weeks of gestation. For babies tested at or before 32 weeks, doctors often use a ’10 by 10′ standard instead, accelerations of at least ten beats per minute lasting at least ten seconds, since research on preterm testing has shown the standard 15 by 15 criteria produces misleadingly nonreactive results in many healthy preterm babies.

A reactive result suggests that the baby is receiving adequate oxygen and that the placenta is functioning properly. Most babies with reactive NSTs are born healthy.

What a Nonreactive NST Looks Like

A nonreactive NST is characterized by the absence of sufficient accelerations or failure to meet the 15 by 15 criteria within the observation period. This does not automatically mean the baby is in distress. It means the test did not show the reassuring pattern doctors look for, and further evaluation is needed.

A nonreactive result can occur for several reasons, some of which are not related to fetal health.

Why Abnormal NST Results Can Be False Positives

An abnormal NST does not always mean the baby is in danger. False positives can occur when the baby is in a sleep cycle, during a calmer time of day, or due to maternal factors such as recent food intake or medication. In these situations, the baby may be perfectly healthy, but the timing of the test did not capture the expected heart rate accelerations.

Because false positives are common, a nonreactive NST is typically followed by additional testing rather than immediate intervention. This is why understanding the next steps is important.

What Happens After an Abnormal NST? Standard Medical Follow-Up

When an NST is nonreactive, clinicians typically order further monitoring or testing before deciding on a course of action. The goal is to gather more information to determine whether the baby is truly in distress or whether the abnormal result was a false positive.

Repeat NST, Biophysical Profile (BPP), and Doppler Ultrasound

One common next step is to repeat the nonstress test after a short period, sometimes after the mother eats or rests, to see if the baby becomes more active and produces a reactive result. If the repeat NST is still nonreactive, the doctor may order a fetal biophysical profile, which combines an ultrasound assessment of fetal movement, muscle tone, breathing movements, and amniotic fluid levels with the NST. The BPP provides a more comprehensive picture of fetal well-being.

In some cases, a Doppler ultrasound may be used to assess blood flow through the umbilical cord and placenta. This can help identify whether the baby is receiving adequate oxygen and nutrients.

When Delivery or Emergency C-Section Becomes Necessary

If additional testing confirms that the baby is not receiving enough oxygen or is showing other signs of distress, the medical team may decide that delivery is necessary. Depending on how far along the pregnancy is and how urgent the situation is, this may mean inducing labor or performing an emergency cesarean section.

The decision to deliver is based on the specific facts of each case, including gestational age, the severity of the findings, and whether the baby’s condition is stable or worsening. In some situations, close monitoring in the hospital may be sufficient until the baby is ready to be born.

How Ignoring an Abnormal NST Can Lead to Birth Injury

While many nonreactive NSTs are false positives, some do indicate genuine fetal distress. When doctors fail to order appropriate follow-up testing, misinterpret the results, or delay necessary intervention, the baby may continue to experience oxygen deprivation, which can lead to serious and permanent injury.

From Nonreactive NST to Fetal Distress (Nonreassuring Fetal Status)

Fetal distress, also called nonreassuring fetal status, means the baby is not receiving enough oxygen. This can be identified through abnormal heart rate patterns, decreased fetal movement, or other signs picked up during monitoring. A nonreactive NST may be one of the first indicators that fetal distress is developing. You can read more about warning signs of fetal distress.

If the medical team does not respond to a nonreactive NST with appropriate follow-up, an underlying problem, such as placental insufficiency or umbilical cord compression, may go on to worsen. The longer the baby goes without adequate oxygen, the greater the risk of injury.

Birth Injuries Linked to Unaddressed Fetal Distress

If severe fetal distress goes unaddressed, it can lead to hypoxic-ischemic encephalopathy (HIE), a type of brain damage caused by oxygen deprivation. HIE can result in cerebral palsy, developmental delays, seizures, and other long-term neurological impairments. In the most tragic cases, prolonged oxygen deprivation can result in stillbirth.

Oxygen deprivation can also affect other organs. Babies who experience severe distress may suffer damage to the heart, kidneys, liver, or lungs, leading to multi-organ failure or long-term health complications.

Not every case of HIE or stillbirth is caused by medical negligence. Birth injuries can occur even when doctors provide appropriate care. However, when a medical team fails to order an NST in a high-risk pregnancy, ignores a nonreactive result, or delays necessary intervention, that failure may constitute negligence under New York law.

Medical Negligence and Your Rights in New York

In New York, doctors and hospitals have a legal duty to provide care that meets accepted medical standards. This includes ordering appropriate tests such as nonstress tests in high-risk pregnancies, interpreting the results correctly, and taking timely action when a nonreactive NST or other warning signs appear.

When Failure to Order or Follow Up on an NST May Be Negligence

Failure to order an NST in a high-risk pregnancy may constitute medical negligence if it contributes to a birth injury, depending on the specific facts of the case. Similarly, if a doctor receives a nonreactive NST result but does not order follow-up testing, misinterprets the findings, or delays delivery when it is medically necessary, that failure may be grounds for a malpractice claim.

Medical negligence cases require showing that the doctor or hospital deviated from the accepted standard of care and that this deviation directly caused the injury. An attorney can review the medical records, consult with experts, and determine whether the care provided fell below the standard.

New York’s Statute of Limitations for Birth Injury Cases

Under New York law, medical malpractice claims generally must be filed within two and a half years of the malpractice. For a child, this period can be extended under New York’s infancy tolling rule, but never beyond ten years from the date of the malpractice. Because missing these deadlines can prevent you from pursuing a claim, consult with a New York birth injury attorney as soon as possible if you believe your child was harmed due to medical negligence. You can read more about how New York’s infant tolling rules apply to birth injury deadlines.

How to Preserve Evidence Through NST Strips and Medical Records

If you are concerned that an abnormal NST was ignored or mishandled, preserving evidence is critical. Request copies of all medical records related to your pregnancy and delivery, including the NST strips, ultrasound reports, labor and delivery notes, and any documentation of fetal monitoring. These records can help an attorney and medical experts determine whether the standard of care was met. You can read more about how to request your child’s medical records in New York.

Do not rely on verbal explanations alone. Medical records provide an objective account of what was done, when it was done, and what the results showed. An experienced attorney can work with medical experts to review these records and identify whether errors occurred.

Questions to Ask Your Doctor After an Abnormal NST

If you receive a nonreactive NST result, ask your doctor the following questions to understand the next steps and ensure you receive appropriate care:

• What does the nonreactive result mean for my baby’s health?

• What follow-up tests or monitoring do you recommend, and when will they be done?

• Could this result be a false positive, and if so, what might have caused it?

• What signs should I watch for at home that would require me to contact you or go to the hospital?

• If the follow-up testing is also abnormal, what are the options for delivery or intervention?

Clear communication with your medical team can help ensure that you understand the plan and that appropriate steps are taken to protect your baby.

When to Contact a New York Birth Injury Attorney

If your baby was diagnosed with a birth injury such as HIE, cerebral palsy, or another condition, and you believe an abnormal NST was ignored or mishandled, contact a New York birth injury attorney. An attorney can review your medical records, consult with experts, and help you understand whether the care you received met the legal standard.

Medical malpractice cases are complex and require detailed knowledge of both medical standards and New York law. An attorney experienced in birth injury cases can evaluate the specific facts of your situation, explain your legal options, and guide you through the process of pursuing a claim if negligence occurred.

You do not need to prove your case before contacting an attorney. Most birth injury attorneys offer free consultations and work on a contingency basis, meaning you do not pay legal fees unless you recover compensation.

FAQ

Does the “15 by 15” Reactive Standard Apply to All Pregnancies?

No. The 15 by 15 standard applies to babies past 32 weeks of gestation. For babies tested at or before 32 weeks, doctors typically use a “10 by 10” standard instead, since a preterm baby’s less mature nervous system means the standard criteria often shows a nonreactive result even in a healthy baby. If your NST was done before 32 weeks, ask which standard was used to interpret it.

If I’m Sent for an NST, Does That Mean My Pregnancy Is High Risk?

Not necessarily a crisis, but it usually means your doctor wants closer monitoring due to a specific factor, such as gestational diabetes, high blood pressure, decreased fetal movement, or being past your due date. Many pregnancies with NST monitoring proceed normally, and the test itself is simply a tool to catch problems early rather than a sign that something has already gone wrong.

How Is an NST Different from the Fetal Monitoring Used During Labor?

An NST is typically done before labor, often in an outpatient setting, to check on the baby over a short window of time. Continuous fetal heart rate monitoring during labor uses similar technology but tracks the baby’s heart rate throughout the entire labor process, including in response to contractions. You can read more about how fetal monitoring strips are read and interpreted during labor.

Can I Request a Copy of My NST Results and Fetal Monitoring Strips?

Yes. You have the right to request copies of your complete prenatal and delivery records, including NST results and fetal monitoring strips. These records show the exact timing and pattern of your baby’s heart rate, which is often central to understanding whether follow-up testing or intervention happened as it should have.

How Much Time Do I Have to Pursue a Legal Claim if My Baby Was Harmed After an Abnormal NST Was Missed?

Under New York law, medical malpractice claims generally must be filed within two and a half years of the malpractice, and for a child, this period can be extended, but never beyond ten years from the date of the malpractice. You can read more about how New York’s infant tolling rules apply to birth injury deadlines.

Understanding Your NST Results and Next Steps

A nonreactive nonstress test is a warning signal, not a diagnosis, and most babies with abnormal NST results go on to be born healthy once appropriate follow-up testing confirms they’re doing well. Understanding the difference between a reactive and nonreactive result, why false positives happen, and what standard follow-up should look like can help you feel more prepared if you’re ever sent for this test. If you have concerns about how your NST results were handled, reviewing your medical records with your care team, and if needed, an attorney, can help you understand what happened.