Standardizing Screening for Preeclampsia Risk Factors to Improve Prescribing of Low-Dose Aspirin : The Journal for Healthcare Quality (JHQ)

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Standardizing Screening for Preeclampsia Risk Factors to Improve Prescribing of Low-Dose Aspirin

Burgess, Adriane; Dalke, Kara; Wheeling, Julia; Clark, Kelley

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doi: 10.1097/JHQ.0000000000000362
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Preeclampsia is one of the most serious health conditions affecting pregnant women and their unborn babies. In the United States, it complicates 3–4% of pregnancies.1 Along with eclampsia, it is responsible for more than one third of severe obstetric complications, is a leading cause of maternal and neonatal mortality,1 and has been shown to increase risk of later-life cardiovascular disease.1-3 Outside of the medical complications associated with preeclampsia there is also a significant economic burden. Hao et al4 reported that the mean combined maternal and infant medical care costs among patients with preeclampsia were $41,790, which were approximately 3 times higher than those who had an uncomplicated delivery ($13,187 [p < .001]). Subsequently, finding and implementing preventative strategies is essential due to both the economic and medical burden of the disease.

Unfortunately, the pathophysiology of preeclampsia is not well defined, and few preventative strategies exist. Most agree that preeclampsia is a multisystem, inflammatory syndrome with multiple hypothetical etiologies including the imbalance of angiogenic factors (prostacyclin and thromboxane A2) and vascular disturbances.1,3,5 Aspirin inhibits cyclooxygenase isoenzymes 1 and 2. COX-1 regulates production of prostacyclin and TXA2, and COX-2 is expressed almost exclusively after exposure to cytokines or other inflammatory mediators.6 This knowledge led to initial studies of low-dose aspirin's effects in preeclampsia prevention.1,5-9

Because of the growing body of research supporting the use of low-dose aspirin therapy (LDAT) for the prevention of preeclampsia, the American College of Obstetricians and Gynecologists (ACOG), the U.S. Preventive Services Task Force (USPSTF), and the Society for Maternal-Fetal Medicine (SMFM) developed guidelines to support the use of LDAT during pregnancy among those at high risk for preeclampsia.1,2,5,6 This article outlines our design and evaluation of the implementation of a preeclampsia risk screen in the electronic health record (EHR) to ensure standardized screening for and provision of LDAT in alignment with evidence-based guidelines.


In 2019, our health system issued a call to action to the Women and Children Service Line to critically evaluate disparities in severe maternal morbidity and mortality for women who deliver within our health system. On evaluating our system-level data, we determined preeclampsia to be a leading cause of morbidity and readmission. Therefore, we embarked on a system-wide project to address clinical care variations related to preeclampsia. In speaking with maternal–fetal medicine and obstetric providers throughout our health system, we determined that there was a gap in the provision of LDAT, and pregnant persons were not being screened for and prescribed LDAT based on the risk factors outlined in evidence-based guidelines.

In 2013, the ACOG issued the “Hypertension in Pregnancy Task Force Report” which recommended daily low-dose aspirin beginning late in the first trimester for women with a history of early-onset preeclampsia and preterm delivery at less than 34 0/7 weeks of gestation or for women with more than one previous pregnancy affected by preeclampsia.2 In 2014, the USPSTF published guidelines outlining high-risk and moderate risk factors for preeclampsia1,5,6 (Table 1); the USPSTF recently reaffirmed these guidelines as of September 28, 2021. The USPSTF (2021) and SMFM recommend that LDAT be prescribed for women with one or more high-risk factors, or with two or more moderate risk factors starting at 12–16 weeks' gestation. Specifically, SMFM recommends that LDAT (81 mg/day) be prescribed for women at high risk for preeclampsia and be initiated between 12 weeks' and 28 weeks' gestation (optimally before 16 weeks) and continued until delivery.6 Subsequently, as a health system, we aimed to standardize the provision of LDAT for those with one or more high-risk or two or more moderate risk factors for preeclampsia.

Table 1. - USPSTF Risk Factors for Preeclampsia1,5,6
High-risk factors Moderate risk factors
History of preeclampsia (especially when accompanied by an adverse outcome)
Multifetal gestation
Renal disease
Autoimmune disease (systemic lupus erythematosus, antiphospholipid syndrome)
Pregestational type 1 or type 2 diabetes
Chronic hypertension
First pregnancy
Maternal age 35 years or older
Body mass index greater than 30
Family history of preeclampsia (mother or sister)
Black persons (due to social, rather than biological factors) (2021) changed from African American race
Low socioeconomic status
Low birthweight or small for gestational age
Previous adverse pregnancy outcome
Greater than 10-year pregnancy interval
In vitro conception (added 2021)

This quality improvement project was performed over a 9-month period (March–November 2020) at 13 obstetrics and gynecology (OB/GYN) and family practice offices which provide obstetric care within our health system. In 2020, there were 5,125 deliveries throughout the system. The project was reviewed by the institutional review board at the study site and deemed not research, and therefore, a formal study review and approval was not necessary. The SQUIRE guidelines were followed when developing this article.

Using the USPSTF (2014) recommendations on the use of “Low-Dose Aspirin for the Prevention of Morbidity and Mortality from Preeclampsia,” a screening tool was built in the EHR. Its development was a collaborative effort between informaticists, nurses, and obstetric care providers. The screening tool consists of both a high-risk and moderate risk screen (Figs. 1 and 2), which includes each of the risk factors identified by the USPSTF (Tables 1 and 2). The screening tool was embedded in the rooming tab in the EHR. Standard work was developed which outlined when and how the screen should be completed.

Figure 1.:
Preeclampsia high-risk assessment. This screening tool shows the high-risk factors and is completed by the clinical staff first. If one high-risk factor is present, an alert will fire for the provider and the moderate screen does not need to be completed.
Figure 2.:
Preeclampsia moderate risk assessment. This screening tool shows the moderate risk factors, if two or more risk factors are present and alert fires for the provider to order low-dose aspirin therapy.
Table 2. - Rates of Screening and Prescribing Low-Dose Aspirin Therapy at the First Prenatal Visit
March to May 2020 June to August 2020 September to November 2020
N = 756 N = 797 N = 818
%(n) %(n) %(n)
Average screening rate at first prenatal visit 74.2% (561) 93.8% (748) 95.6% (782)
Positive screen requiring LDAT 41% (230) 37.5% (281) 39.6% (310)
LDAT prescribed 81.3%(187) 92.5% (260) 97.1% (301)
LDAT, low-dose aspirin therapy.

The screen is completed by the office nurse at the time the patient is roomed during their first prenatal visit with the obstetric care provider. Patients who are greater than 28 weeks' gestation at the time of their first visit are excluded from screening. To streamline the process, patients are first asked about high-risk factors for preeclampsia. If no high-risk factors are present, then patients are screened for moderate risk factors. This helps to decrease the time necessary to complete the screen. On completion of the screen, if the patient has one high-risk factor or two or more moderate risk factors for preeclampsia, a best practice advisory (BPA) is triggered in the EHR and fires for the obstetric care provider when they log into the patient's chart (Fig. 3). The BPA notifies the provider, based on the patient's risk factors, LDAT is recommended. The BPA serves as an advisory which outlines the patient's risk factors and includes a link to the low-dose aspirin order so that the obstetric provider can easily order aspirin after discussion with the patient and if appropriate. The BPA also allows the provider to document why LDAT was not initiated if risk factors were present or if the patient declined.

Figure 3.:
Low-dose aspirin therapy best practice advisory. This shows the best practice advisory, alert, that pops up for the OB providers signaling the patient is at high risk for preeclampsia and aspirin should be ordered.

With an understanding that systemic factors further contribute to disparities, and to promote adherence to aspirin therapy, patients were provided a free 1-month sample of aspirin at the time it was prescribed. In addition, although aspirin can be purchased inexpensively, we asked providers to enter a prescription in the EHR for aspirin, as it was most often without direct cost to the patient when prescribed.

Our screen went live in our EHR the end of February 2020. On rollout of this initiative to system OB/GYN and family practice offices, a PowerPoint with education on the initiative was provided to office staff and providers. In-person education was also offered to each office. The initiative was presented at Clinical Effectiveness Councils and department and site director meetings to further encourage provider buy-in. A dashboard was created to monitor each obstetrical care site's compliance with screening for and prescribing of LDAT at the first prenatal visit. The Women and Children Service Line Obstetric Program Manager reviewed the EHR of any patient not screened and of those who screened positive but did not have LDAT ordered. On review, the practice was made aware of any unscreened patients and asked to complete the screening and follow-up as appropriate. In addition, documentation was searched for reasons why aspirin was not ordered among patients at high risk, reasons for not prescribing include aspirin allergy, already on thromboprophylaxis, patient refusal, or the provider deemed that LDAT was inappropriate after reviewing the patient's risk factors or after discussion with the patient.


During the first 3-month period (March–May 2020) after rollout of the preeclampsia screen in our EHR to assess for the need for LDAT, the average rate of screening during the first prenatal visit at all offices was 74.2% (n = 561). Screening rates at individual offices during this period ranged from 0% to 100%. Education to individual offices continued, and in the second 3-month period (June–August 2020), the average overall screening rate increased to 93.8% (n = 748), with rates of screening at individual OB/GYN offices ranging from 65.2% to 100%. After the third 3-month period (September–November 2020), we achieved a 95.6% (n = 782) average screening rate during the first prenatal visit at all offices throughout our health system.

Of those screened March to May 2020, 41% (n = 230) had one or more high-risk factors or two or more moderate risk factors which is a positive screen and should have been prescribed aspirin. Of those screened June to August 2020, 37.5% (n = 281) screened positive, and from September to November 2020, 39.6% (n = 310) screened positive and should have been provided a prescription for LDAT based on their risk factors.

To ensure those who screened at high risk for preeclampsia were prescribed aspirin, we assessed rates of provider prescribing. During March to May 2020, among those who screened positive, 81.3% (n = 187) were prescribed aspirin as recommended by guidelines. Our adherence to prescribing continued to improve, and between June and August 2020, 92.5% (n = 260) of those who screened positive for risk factors were prescribed aspirin, and from September to November 2020, 97.1% (n = 301) were prescribed LDAT appropriately (Table 2).


We noted increased rates of screening for and prescribing of LDAT with the implementation of the EHR-embedded screening tool; however, this improvement may also have been associated with the increased surveillance of screening and prescribing our leadership team used as part of the quality improvement process. In addition, we recognize that additional resources are needed from informatics teams to build tools within the EHR to standardize workflows that promote universal screening. Informatics resources may not be available, which would affect other hospitals' or health systems' ability to replicate this quality improvement project. Initially, we noted variation in compliance with screening by office. We believe this may have be associated with varying engagement with system-level quality improvement work; however, with the provision of monthly feedback on office-level adherence to screening by the Women and Children Service Line Obstetric Program Manager, teams became increasingly engaged with the work.


Embedding a screening tool in the EHR at the time of the first prenatal visit has dramatically improved the standardized assessment for and prescription of LDAT for women at high risk of preeclampsia in our hospital system. Understanding that common risk factors for preeclampsia may be inadvertently missed, the SMFM Patient Safety10 and Quality Committee published a checklist to improve the probability of aspirin being recommended for all appropriate candidates. The SMFM believes that the routine use of checklists facilitates thorough assessment and helps to minimize errors of omission. Our development and use of an EHR-embedded screening tool to assess for risk factors for preeclampsia and encourage appropriate prescribing of LDAT resulted in much improved screening and prescribing practices. Although the SMFM supports the use of either a paper or electronic checklist, embedding the screening tool into the EHR allows for easier monitoring of adherence to screening, clear documentation of preeclampsia risk factors, and easier prescribing of LDAT by embedding a best practice advisory within the screening.

Low socioeconomic status was the most challenging USPSTF risk factor to operationalize into our screening tool with information standardly obtained by office staff. After reviewing public health literature for proxies for low socioeconomic status, we decided we would use less than high-school education as a proxy for low social economic status as this was easy for office staff to assess and was a concrete measure that office staff felt comfortable asking of patients.11

Mallampati et al12 completed a decision analysis to compare preeclampsia-related costs and effects of four strategies to initiate aspirin use in pregnancy before 16 weeks' gestation to prevent preeclampsia. Mallampati et al12 found that under a wide range of conditions, universal aspirin administration in pregnancy is the preferred strategy for preeclampsia prevention. However, at this time, universal prescribing of LDAT is not recommended by professional societies. Mallampati et al found that the use of the USPSTF guidelines for provision of LDAT was more effective than no aspirin in reducing healthcare cost and preventing preeclampsia. In their case analysis, Mallampati et al12 assumed that 28% of women would screen positive for the need for LDAT based on the USPSTF guidelines. In our study, 37–41% of women screened positive for the need for LDAT due to one or more high-risk or two or more moderate risk factors for preeclampsia. The Surgeon General's Call to Action to Improve Maternal Health (2020) reported that rates of chronic hypertension among childbearing women is increasing, thus increasing the risk of superimposed preeclampsia.13 Rates of CHTN among pregnant women may be a result of higher rates of maternal obesity and older maternal age at the time of delivery.13 Subsequently, it is possible that LDAT could prevent even more cases of preeclampsia and result in even additional cost savings then outlined by Mallampati et al (2019).

Hypertensive disorders of pregnancy disproportionately affect minority women; these women also have a higher risk of adverse outcomes, severe maternal morbidity, and in-hospital mortality associated with preeclampsia.14 In addition, Black women with chronic hypertension more often have end-organ dysfunction associated with their hypertensive disease than their White counterparts.14 With that said, the USPSTF (2021) includes Black race as a moderate risk factor for preeclampsia due to social, rather than biological, factors.1 The SMFM recommends that clinical protocols include algorithms that identify women at high risk based on racial or ethnic background. Without these algorithms, patients may not be treated appropriately which could further contribute to disparities in outcomes.14 Subsequently, in their summary of recommendations to improve clinical care and address disparities, SMFM called out that the standardized use of preventative therapies such as LDAT can improve outcomes and result in lower healthcare cost.14 Providing preventative therapies such as LDAT cannot prevent outcomes perpetuated by racial bias, disparities in resource availability and access, and structural and systemic racism pregnant people of color encounter during prenatal care, labor, and birth. Health systems must prioritize work to address bias and disparities to truly achieve equity in maternal outcomes.


We continue to surveil the use of the screening tool and appropriate prescribing of LDAT based on risk factors. The provision of LDAT to patients at high risk for preeclampsia has the potential to decrease risk for the disease and its associated maternal and neonatal morbidity and mortality. Obstetric care providers should partner with informaticists to embed workflows in the EHR to standardly assess pregnant individuals for risk factors for preeclampsia and ensure the standardized provision of LDAT early in pregnancy when appropriate.


This preeclampsia risk screen embedded in the EHR and the standardization of office workflow encouraged universal screening of pregnant persons in the first trimester for preeclampsia and encouraged prescribing of LDAT if appropriate. Our screening tool was developed based on maternal risk factors only as outlined by the USPSTF (2014). On September 28, 2021, the USPSTF reaffirmed their recommendation on the use of LDAT for the prevention of preeclampsia and added invitro conception as a moderate risk factor—we will update our screening tool accordingly. The patient data needed to answer the screening questions are easily and quickly collected from the patient or their medical record further supporting its ease of use. It is important to note that recently, the International Federation of Gynecology and Obstetrics has suggested moving toward a first trimester combined screening which includes maternal risk factors and biomarkers (measurements of mean arterial pressure), serum placental growth factor, and uterine artery pulsatility index.15 However, the use of combined screening will prove much more challenging and costly to implement due to the additional biomarker testing necessary. Currently, the ACOG considers combined testing investigational.16 Although our study outlined a strategy to increase screening and prescribing of LDAT to reduce the risk of preeclampsia, patient adherence to the prescribed therapy is integral to seeing improved outcomes. van Montfort et al17 suggested that clear communication with patients about their risk of preeclampsia and counseling regarding risks and benefits associated with LDAT may positively influence women's adherence with the recommended therapy. As a health system, we continue to review each offices adherence to screening for and prescribing of LDAT at the first OB visit and have begun to assess the impact the standardized provision of LDAT has had on rates of preeclampsia within our health system.

Authors' Biographies

Adriane Burgess, PhD, RNC-OB, CCE, CNE. C-ONQS, is the Program Director for the Women and Children Service Line at WellSpan Health, York, PA. Dr. Burgess is responsible for quality improvement and data analytics for all inpatient and outpatient obstetric, gynecologic, and newborn care services for WellSpan Health.

Kara Dalke, MD, MPH, is a board-certified obstetrician and gynecologist with a master’s in public health. She most recently worked as an OB hospitalist managing the inpatient care of pregnant and postpartum persons. She currently resides in Virginia.

Julia Wheeling, BSN, MBA, RN, C-ONQS, is the Program Manager-Obstetrics for the Women and Children Service Line at WellSpan Health, York, PA. Julia develops, implements, and coordinates obstetric services across the continuum of care.

Kelley Clark, MD, is a Maternal–Fetal Medicine Specialist and Practice Administrator for WellSpan Maternal–Fetal Medicine, York, PA. Dr. Clark is board-certified in obstetrics and gynecology and in maternal and fetal medicine. She manages the care of patients with high-risk perinatal conditions and provides clinical expertise on system-wide initiatives related to perinatal care.


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low-dose aspirin therapy; preeclampsia; electronic health record; screening

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