Final Research Plan

Preeclampsia: Screening

August 14, 2014

Recommendations made by the USPSTF are independent of the U.S. government. They should not be construed as an official position of the Agency for Healthcare Research and Quality or the U.S. Department of Health and Human Services.

The final Research Plan is used to guide a systematic review of the evidence by researchers at an Evidence-based Practice Center. The resulting Evidence Review will form the basis of the USPSTF Recommendation Statement on this topic.

The draft Research Plan was available for comment from May 22 until June 18, 2014 at 5:00 p.m., ET.

  1. How effectively does screening for preeclampsia reduce maternal and perinatal morbidity and mortality, and does effectiveness differ by screening protocol (e.g., tests used, timing of tests, rescreen intervals) or preeclampsia risk status?
  2. What is the effectiveness of risk assessment in early pregnancy for identifying women at high risk for preeclampsia?
  3. What are the harms of preeclampsia risk assessment?
  4. How effectively do screening tests (e.g., blood pressure, proteinuria) identify women with preeclampsia?
    1. How accurate are different screening tests for proteinuria?
    2. How effective are different screening protocols (e.g., instruments, test procedures, timing of tests, rescreen intervals) for identifying women with preeclampsia?
    3. How should women at high risk for preeclampsia be screened differently from women at low or average risk?
  5. What are the harms of screening for preeclampsia and do they differ by risk status or screening protocol?

Contextual questions will not be systematically reviewed and are not shown in the Analytic Framework.

  1. Do preeclampsia screening or risk assessment perform differently for important population subgroups (e.g., racial or ethnic minorities, nulliparous women, women at high risk)?
  2. For women without proteinuria who have hypertension in pregnancy, what other screening tests should be considered given new diagnostic criteria?
  3. What established protocols for preeclampsia management and treatment are known to reduce morbidity and mortality?

The Research Approach identifies the study characteristics and criteria that the Evidence-based Practice Center will use to search for publications and to determine whether identified studies should be included or excluded from the Evidence Review. Criteria are overarching as well specific to each of the key questions (KQs).

  Include Exclude
Population All asymptomatic pregnant women Studies that exclusively include persons seeking high-risk obstetric care; other selected nongeneralizable populations
Disease/Condition Preeclampsia  
Interventions: Preeclampsia risk assessment and screening KQs 1, 4, 5: Screening tests for preeclampsia (e.g., blood pressure, urinalysis, serum tests for renal insufficiency)

KQs 2, 3: Identification of women at high risk for preeclampsia using information obtained from patient history or measurements routinely collected in primary care (e.g., blood pressure, body mass index)

Experimental tests not routinely used in clinical practice

Secondary evaluations and tests used to assess preeclampsia severity or confirm diagnosis in symptomatic women

Not routinely collected serum markers (e.g., angiogenic factors), genetic susceptibility markers, and ultrasound measurements (e.g., Doppler ultrasound pulsatility index or resistance index)

Comparisons KQ 1: No screening, different screening protocols (e.g., modality, timing, rescreen intervals), and screening women at high risk for preeclampsia

KQs 2, 3: Maternal characteristics and routinely collected clinical measures associated with preeclampsia diagnosis

KQs 4, 5: Different blood pressure and proteinuria screening protocols (e.g., instrument, procedure, timing, frequency) and screening protocols compared with preeclampsia risk status

Outcomes Maternal and perinatal health outcomes (KQ 1): Maternal mortality and serious morbidity (e.g., organ or system failure or injury, eclampsia) and perinatal or neonatal mortality and serious morbidity (e.g., intrauterine growth restriction, low birthweight, brain injury)

Intermediate outcomes (KQs 2, 4): Preeclampsia incidence and proteinuria screening test performance characteristics

Harms (KQs 3, 5): Misclassification, increased monitoring, false-positive results, overdiagnosis, overtreatment (e.g., failed induction, Cesarean section, induced preterm birth, hypermagnesemia), and patient stress and anxiety

Nonclinical health outcomes, such as length of hospital stay (without indication), intensive care unit admission, or neonatal intensive care unit admission
Setting Primary care settings for obstetric care (e.g., obstetrician gynecologists, family physicians, certified nurse midwives)

Countries categorized as “very high” or equivalent on the Human Development Index (as defined by the United Nations Development Program)

Clinics and study sites treating only high risk maternity patients

Countries not categorized as “very high” by the Human Development Index or not applicable to U.S. clinical settings or populations

Study designs Screening health outcome benefits (KQ 1): RCTs, cohort studies

Risk assessment tools and risk factors (KQ 2): RCTs, cohort studies, instrument validation studies, and test accuracy studies

Effectiveness of screening for detecting preeclampsia and accuracy of proteinuria screening tests (KQ 4): RCTs, cohort studies, instrument validation studies, and test accuracy studies

Risk assessment and screening harms (KQs 3, 5): RCTs or observational studies (e.g., case series, cohort, registry, survey data)

Screening benefits (KQ 1): Editorial, narrative review, commentary, postmarketing surveillance, and case reports

Risk assessment tools and risk factors (KQ 2): Editorial, narrative review, commentary, postmarketing surveillance, and case reports

Screening effectiveness (KQ 4): Editorial, narrative review, commentary, postmarketing surveillance, and case reports

Harms (KQs 3, 5): Editorial, narrative review, commentary, postmarketing surveillance, and case reports

Publication dates Studies published after January 1990, all references from the previous USPSTF review, and eligible studies identified through a bridge search Studies published before 1990
Study quality Good and fair quality Poor quality
Language English Non-English studies

Abbreviations: RCT = randomized, controlled trial; USPSTF = U.S. Preventive Services Task Force.

The draft research plan was posted for public comment from May 22 to June 18, 2014. We received comments from nine public commenters and partner organizations. Minor clarifying text was added as suggested, however, there were no major changes made to the research plan that altered the scope of the review or our approach to synthesizing the evidence.