By NPWH Board Member Jennifer Hawn, MSN, WHNP-BC
Preeclampsia; the masked evader. When does it start? Where does it start? Who will it effect? How do we stop it? These are all difficult questions that clinical providers have yet to fully understand. One thing is for sure, the staggering effects of Preeclampsia on the outcome of pregnancies impact both maternal and fetal health. But we are also beginning to understand that one of the best prevention strategies is not some NIH developed new intervention or new pharma R&D brainchild. It’s something in most patients’ medicine cabinets that costs only pennies: low-dose Aspirin.
The Dangers of Preeclampsia:
According to evidence collected by the United States Preventative Services Task Force (USPSTF):
- Preeclampsia is the leading cause of maternal death, effecting 3.8% of pregnancies in the U.S.
- Twelve percent of maternal deaths are due to effects of Preeclampsia
- 97% of preeclampsia related deaths occur in the postpartum period
- The morbidity and mortality of preeclampsia also affects neonates causing 15% of preterm births (<37 weeks gestation)
- Prematurity alone is responsible for 70% of neonatal mortality and 75% of neonatal morbidity in developed countries
Due to the potential lifelong effects of prematurity, the cost associated with preterm birth and other maternal complications at the time of delivery and postpartum period, it is easy to see why Preeclampsia remains such a hot topic of discussion.
The Best-Known Prevention Strategy
As Advanced Practice Nurses, it is embedded in us that prevention is the key to minimizing disease and Preeclampsia is proving to be no different. Educating our patients is key to recognizing preeclampsia at its earliest manifestation for effective management and treatment, however, additional evidence continues to support the use of low dose Aspirin (81mg) daily after 12 weeks gestation for the prevention of Preeclampsia. While the evidence is unclear when the most benefit of this regimen occurs, it is widely accepted based on literature review that treatment of Aspirin 75 mg or greater, sometime in the late first trimester (>12 weeks) but before approximately 16 weeks has yielded the best results. (There are no specific recommendations on when the Aspirin should be discontinued in the third trimester.) This strategy is supported by further evidence that suggests preeclampsia is a combination of factors that begin in the first trimester related to unusual placental development that results in placental ischemia and the release of inflammatory and oxidative stress factors into the maternal blood stream – hence the use of an “anti-inflammatory” medication – Aspirin.
What does low dose Aspirin have to offer? It does not magically prevent preeclampsia 100%. The risk reduction for women who are at high risk for Preeclampsia is believed to be approximately 10% and a 20% reduction in perinatal mortality. In studies, treatment with low dose Aspirin was associated with an absolute risk reduction of 2-5% for Preeclampsia, 1-5% for Intrauterine Growth Restriction (IUGR) and 2-4% for preterm birth. IUGR also increases the risk of neonatal respiratory distress, seizures, sepsis and long-term disability even when born at term, so a small reduction in IUGR infants can have a remarkable impact on their quality of life. Additionally, treatment has also been associated with an average birth weight increase of 130 grams.
Given that low dose Aspirin costs somewhere around a penny or so per pill and is conveniently obtained at any retail pharmacy, it is easy to see why we should be consistent in prescribing this for our patients who are at risk for Preeclampsia.
Knowing the Risks
So, what are the risks of treatment? A question we should continually ask ourselves when it comes to treatment of disease, regardless of the seeming innocence of the treatment. As an Antiplatelet Aggregate Inhibitor, Aspirin inherently carries the reputation of risk, especially in the face of potential surgery and blood loss associated with delivery, which is the only known intervention for initiating resolution of Preeclampsia. Thus far, no known complications with the use of low dose Aspirin therapy for women who are at high risk for the development of preeclampsia have been identified. Specifically, studies have not found any adverse effects related to increased risk of maternal hemorrhage, mean blood loss, placental abruption, neonatal intracranial hemorrhage or developmental milestones at age 18 months.
Who is a Candidate for Low-Dose Aspirin Therapy?
So, now that we know what to prescribe and why, Advanced Practice Nurses need to be experts in deciding who is a candidate for the use of low dose Aspirin therapy in pregnancy. The USPSTF identifies that this treatment is best suited for women who are considered “high risk” for the development of preeclampsia. Answering the question of “Who is this appropriate for” can be identified easily with a comprehensive health history.
It may be beneficial to create a screening tool for your practice that can be used in the process of interviewing new patients so the opportunity to initiate low dose Aspirin at the appropriate time in pregnancy is not overlooked.
While it is impossible to predict which women will have severe features of Preeclampsia and those who will not (a topic for another blog entry), it is widely accepted that women with the following are at increased risk:
- Histories of Preeclampsia
- Autoimmune disease (Lupus and Antiphospholipid Syndrome)
- Chronic Hypertension
- Renal disease
- Those carrying multiples
However, other moderate risk factors also include women who are nulliparous, advanced maternal age (>40 years), between pregnancy interval >10 years, Body Mass Index (BMI) >35 and a family history of preeclampsia (mother or sister).
What Does this Mean for Advanced Practice Nurses?
Given that we usually see patients several weeks before they visit a Maternal Fetal Medicine specialist, it’s important for all Advanced Practice Nurses caring for child bearing women to screen for Preeclampsia and recommend low-dose Aspirin for the appropriate patients. This simple step – for pennies on the dollar – can make a priceless difference in maternal and fetal health.
- ACOG: Hypertension in Pregnancy (2013)
- USPSTF: Low-Dose Aspirin use for the Prevention of Morbidity and Mortality from Preeclampsia
- ACOG Low Dose Aspirin Practice Advisory (2016)
- Preeclampsia Registry
- Preeclampsia Foundation
- California Maternal Quality Care Collaborative – Preeclampsia Toolkit