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OB Early Warning Criteria

1 Contact Hour
This peer reviewed course is applicable for the following professions:
Advanced Practice Registered Nurse (APRN), Clinical Nurse Specialist (CNS), Licensed Practical Nurse (LPN), Licensed Vocational Nurses (LVN), Midwife (MW), Nursing Student, Registered Nurse (RN)
This course will be updated or discontinued on or before Saturday, January 13, 2024

Nationally Accredited

CEUFast, Inc. is accredited as a provider of nursing continuing professional development by the American Nurses Credentialing Center's Commission on Accreditation. ANCC Provider number #P0274.


Participants will know how to use early warning criteria.


After completing this continuing education course, the participant will be able to:

  1. Define early warning criteria.
  2. Identify the main reason why early warning criteria are essential.
  3. Identify when to activate a response to early warning criteria.
  4. Identify barriers to early warning criteria implementation.
  5. Create a plan to implement the early warning criteria in their hospital.
CEUFast Inc. and the course planners for this educational activity do not have any relevant financial relationship(s) to disclose with ineligible companies whose primary business is producing, marketing, selling, re-selling, or distributing healthcare products used by or on patients.

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To earn of certificate of completion you have one of two options:
  1. Take test and pass with a score of at least 80%
  2. Reflect on practice impact by completing self-reflection, self-assessment and course evaluation.
    (NOTE: Some approval agencies and organizations require you to take a test and self reflection is NOT an option.)
Author:    Kelly LaMonica (DNP(c), MSN, RNC-OB, EFM)


Monitoring, also known as clinical surveillance, is ongoing patient assessments, which will identify problems and trigger responses.1 A warning system is a process that defines observation criteria and sets a limit to trigger a response.1 Although non-obstetric warning systems have existed for nearly twenty years, there has not been a system to use for obstetric women until recently.

Maternal morbidity and mortality are still on the rise in the United States. Severe maternal morbidity has risen over 200% in the United States from 1993 to 2014.2 There are some known reasons for this increase; increases in maternal age, pre-pregnancy obesity, preexisting chronic medical conditions, and cesarean delivery.3 Hemorrhage, hypertension, infection, and venous thrombosis with delays in recognition, diagnosis, and treatment are the cause of many preventable maternal deaths.1

From 2003 to 2005, the Saving Mothers’ Lives report recommended a modified early obstetric warning system. This system assessed vital signs and scored the woman based on the results. An algorithm was then used to determine what the woman needed. The score showed whether the woman was fine, needed closer monitoring, or needed immediate attention.4

Current Evidence of Early Warning Criteria

After several studies, it was determined that a single-parameter risk assessment system that favors simplicity and specificity over complexity and sensitivity would be easier with an increase in patient specificity. Maternal mortality reviews have shown that in women who died, a disproportionate number demonstrated frankly abnormal vital signs, suggesting that a single-parameter system should maximize specificity for patients who are developing a critical illness.1 The maternal early warning criteria were created based on what these reviews have shown.

Table 1: The Maternal Early Warning Criteria
Systolic BP (mm Hg) <90 or >160
Diastolic BP (mm Hg) >100
Heart rate (beats per min) <50 or >120
Respiratory rate (breaths per min) <10 or >30
Oxygen saturation on room air, at sea level,%


Oliguria, mL/hr for ≥2 hours <35
Maternal agitation, confusion, or unresponsiveness
Patient with preeclampsia reporting a non-remitting headache or shortness of breath

Note. BP = blood pressure.

These triggers cannot address every possible clinical scenario that could be faced by an obstetric clinician and must not replace clinical judgment. As a core safety principal, the bedside nurse should always feel comfortable with escalating concerns at any point.1

Activating Early Warning Criteria

All women who meet any of The Maternal Early Warning Criteria should receive prompt bedside evaluation by a physician with the ability to activate resources in order to initiate emergency diagnostic and therapeutic interventions as needed.1 It is important to note that one abnormal measure could have been inaccurate; therefore, it should be repeated. If the patient's provider is unavailable for a prompt evaluation, a covering provider should evaluate the patient. If a woman meets criteria and the reason cannot be determined, a maternal-fetal medicine consult, a hospital intensivist consult, or a rapid response team action initiated. Some electronic medical records can be programmed to alert the RN and page appropriate resources (such as the attending physician) when the patient meets criteria.

Barriers to Early Warning Criteria

The most significant barrier to implementing an early warning criteria system is physician and administration buy-in. Providers may not want to be bothered, especially when they are not available. It is crucial to have an in-house provider to cover these circumstances. However, many providers are reluctant to respond to and treat another provider's patients. Nurses who are making the call to the provider may have a difficult time calling a provider who will not respond appropriately. It is vital for hospital administration to support an early warning criteria policy and ensures that providers follow it. Nurses may improve the use of the criteria if they receive praise or acknowledgment for using the criteria appropriately.

Creating a Policy

The Council on Patient Safety in Women’s Healthcare, a subcommittee of the American College of Obstetrics and Gynecology (ACOG) and the Association of Women’s Health, Obstetric, and Neonatal Nursing (AWHONN) both support the use of maternal early warning criteria. The findings in maternal morbidity reviews support the use as well.5

California Pregnancy Associated Mortality Review 2002-2005
Delayed Response to triggers
Postpartum hemorrhage85%
Cerebrovascular disease63%
Venous thromboembolism75%
Amniotic fluid embolism67%

Each hospital should have a policy that includes the criteria to trigger the early warning system, whom to notify, how to notify them, how rapidly to expect a response, and when and how to activate the clinical chain of command in order to ensure an appropriate response.5

Provider Notification

If the attending physician is immediately available, he/she will provide bedside evaluation of the patient within 10 minutes. If the attending physician is not immediately available, the RN will call the in-house OB to provide bedside evaluation of the patient within 10 minutes. The attending physician or CNM will also receive notification of the patient's status. If the CNM is notified, he/she will notify the attending physician. If in-house OB is called but not immediately available, he/she will receive a verbal report and determine what further action is necessary.

Provider Actions

When called to the bedside, the physician will document by writing a note which includes but is not limited to differential diagnosis, planned frequency of monitoring and re-evaluation, criteria for immediate physician notification, any diagnostic or therapeutic interventions. The physician will communicate the assessment and plan via a “huddle.” Huddle participants include the Primary RN, the Charge RN, the Anesthesiologist, the attending physician if present, and the in-house OB. If MEWS conditions(s) persist after corrective measures undertaken, then MFM consult should be requested. Additionally, the intensivist consult and Rapid Response Team may activate.

If the RN and the charge nurse question any aspect of the patient's care and no resolution is forthcoming with the attending physician, another appropriate physician and a nurse in the Nursing Chain of Command will receive a notification. It is essential that nurses have support in this process.


Maternal early warning criteria can prevent maternal mortality. There are studies to support the effectiveness of these criteria. There are cases of complications such as preeclampsia that may not be preventable, but prompt treatment may prevent maternal morbidity or mortality. All nurses should know these criteria and have a process to activate a response.

Case Study

Patient M.S. is a 42-year-old who delivered her first baby via c-section 3 hours ago. She had moderate to heavy bleeding during her recovery. Her estimated blood loss measured 1200mL. Her vital signs have been stable. She transfers to the mother-baby unit at 11 pm. She begins to complain of severe abdominal pain. She is given Dilaudid for the pain of 9 out of 10 on the pain scale. Her bleeding is moderate. Her BP is 128/84, HR 140, respirations 18, temp 98.6. Her pulse ox is 98% on room air, and her urine output is adequate. The RN assumes the elevated HR is due to her pain. The RN returns in 1 hour to check on this patient and finds her lethargic with a BP 90/60, HR 150, pulse ox 94%. The RN calls a rapid response. The patient ends up in the OR with a massive hemorrhage requiring a massive transfusion and transfers to ICU.

  1. Were the RN's actions appropriate?
  2. Should the early warning criteria have been activated?
  3. Could the massive transfusion have been prevented?

At 11pm, the patient’s HR met early warning criteria. The HR should have been rechecked and the provider called. The RN’s actions were not appropriate. HR could be elevated due to pain, but the woman had already had a hemorrhage and her bleeding was still moderate. A massive transfusion may have been prevented if the patient was treated with blood products sooner, but it is impossible to say it was preventable. The woman should have received care sooner though.

Select one of the following methods to complete this course.

Take TestPass an exam testing your knowledge of the course material.
Reflect on Practice ImpactDescribe how this course will impact your practice.   (No Test)


  1. Mhyre JM, Doria R, Hameed AB, et al. The Maternal Early Warning Criteria: A Proposal from the National Partnership for Maternal Safety. Journal of Obstetric, Gynecologic & Neonatal Nursing. 2014;43(6):771-779. DOI:10.1111/1552-6909.12504.
  2. Severe Maternal Morbidity in the United States | Pregnancy. Accessed December 1, 2019. Visit Source.
  3. Queenan JT. Protocols for High-Risk Pregnancies: An Evidence-Based Approach. Wiley-Blackwell; 2015.
  4. Behling DJ, Renaud M. Development of an Obstetric Vital Sign Alert to Improve Outcomes in Acute Care Obstetrics. Nursing for Women's Health. 2015;19(2):128-141. DOI:10.1111/1751-486x.12185.
  5. Maternal Early Warning Criteria. Council on Patient Safety in Women's Health Care. Published June 11, 2019. Accessed December 5, 2019. Visit Source.