Published 9 September 2009, doi:10.1136/bmj.b3129
Cite this as: BMJ 2009;339:b3129

Practice

Guidelines

Assessing the onset of pre-eclampsia in the hospital day unit: summary of the pre-eclampsia guideline (PRECOG II)

¹ Action on Pre-eclampsia, Syston LE7 1LD, ² Nuffield Department of Obstetrics and Gynaecology, John Radcliffe Hospital Oxford OX3 9DU, ³ Academic Head of Paediatrics, Obstetrics and Gynaecology, St James’s University Hospital, Leeds LS9 7TF, ⁴ NIHR Biomedical Research Centre, St Mary’s Hospital, University of Manchester, Manchester M13 0JH, ⁵ John Radcliffe Hospital, Oxford OX3 9DU, ⁶ Horton Maternity Hospital, Banbury OX16 9AL, ⁷ Mourne House, Maresfield Gardens NW3 5SL, ⁸ Royal College of Midwives, London W1G 9NH, ⁹ Worcestershire Royal Hospital, Worcester WR5 1DD, ¹⁰ St Thomas’ Hospital, London SE1 7EH, ¹¹ Fetal Medicine, Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne NE2 4HH, ¹² King’s College London, St Thomas’ Hospital, London SE1 7EH, ¹³ St James’s University Hospital, Leeds LS9 7TF, ¹⁴ Royal Victoria Hospital, Newcastle upon Tyne NE1 4LP

Why read this summary?

Pre-eclampsia remains a leading cause of maternal death, with 72% of pre-eclampsia cases associated with substandard care.¹ One in 10 pregnant women develop partial signs or symptoms (73 000 a year in the United Kingdom); about 20% of these progress to pre-eclampsia.^{2 3} This article summarises recommendations from the Pre-Eclampsia Community Guideline (PRECOG) Group⁴ under the auspices of the charity Action on Pre-eclampsia. The recommendations cover the assessment of women with suspected pre-eclampsia by hospital midwives in day assessment units and complements our previous community based advice.^{5 6}

Recommendations

PRECOG recommendations (see table 1 for definitions used) are based on systematic review of evidence and expert consensus, graded A, B, C, or D; a "good practice point"(GPP) is based on the guideline development group’s experience (box 1). The grading is shown in parentheses after each recommendation.

View this table: [in this window] [in a new window]   Table 1  Definitions used in the PRECOG recommendations

 

Box 1 Levels of evidence on which recommendations are based* Grading of recommendations Grade A—Directly based on category I evidence Grade B—Directly based on category II evidence or extrapolated recommendation from category I evidence Grade C—Directly based on category III evidence or extrapolated recommendation from category I or II evidence Grade D—Directly based on category IV evidence or extrapolated recommendation from category I, II, or III evidence GPP (good practice point)—Based on the view of the guideline development group Grading (level) of evidence Level Ia—Evidence obtained from meta-analysis of randomised controlled trials Level Ib—Evidence obtained from at least one randomised controlled trial Level IIa—Evidence obtained from at least one well designed, controlled study without randomisation. Includes cohort studies Level IIb— Evidence obtained from at least one other type of well designed, quasi-experimental study. Includes case-control studies Level III—Evidence obtained from well designed, non-experimental descriptive studies, such as comparative studies, correlation studies, and case studies Level IV—Evidence obtained from expert committee reports or opinions, and/or clinical experience of respected authorities *Based on a scheme proposed by the US Agency for HealthCare Policy and Research7 and used in the National Institute for Health and Clinical Excellence’s 2003 guideline on antenatal care8 For further details see full guidance4 and methodology.9

Midwives in a day assessment unit should offer women the following step-wise investigations and management.

Step 1
For all referrals for suspected pre-eclampsia

• Take a history, including checking for PRECOG risk factors for pre-eclampsia (table 2) (B/C)
  
• Confirm the presence of any one of new hypertension (B), new proteinuria (B), maternal symptoms of pre-eclampsia (such as headache, visual disturbances, epigastric pain, vomiting) (C), and clinical suspicion of fetal compromise (B)
  
• Measure blood pressure with equipment that is accurate in individual hypertensive pregnant women (C). Use appropriate cuff size (C)—thigh cuffs (18x36 cm) for women with an arm circumference of 41 cm or more. Follow PRECOG recommendation 6 for reducing errors in blood pressure measurement⁶ (C, D, GPP)
  
• Estimate proteinuria by dipsticks (C) and follow PRECOG recommendation 7 to improve reliability.⁶ Accuracy is not increased by retesting a new sample [GPP]. Use the higher of the dipstick results from the community and the day assessment unit [GPP]
  

View this table: [in this window] [in a new window]   Table 2 Factors that can be measured early in pregnancy that increase the likelihood of pre-eclampsia in any given pregnancy6

 
Step 2
For suspicion of fetal compromise and/or maternal symptoms

• Follow local protocols.
  

For new hypertension (no maternal symptoms or fetal compromise)

• Admit women with a diastolic blood pressure 110 mm Hg or systolic blood pressure 170 mm Hg (D).
  
• Arrange a medical review to consider admission for women with a diastolic blood pressure 100-109 mm Hg or systolic blood pressure 160-169 mm Hg (D).
  
• Measure the platelet count, liver function (aspartate aminotransferase or alanine aminotransferase), and serum creatinine for women with a diastolic blood pressure 90-99 mm Hg. Do not test for serum urate if proteinuria is not present. Use pregnancy specific ranges (table 3, box 2) (C); do not use results to predict subsequent pre-eclampsia (C). Use results to identify features of HELLP syndrome (name derived from its features: Haemolysis, Elevated Liver enzymes, and Low Platelet count) and underlying concurrent conditions, and as a baseline to determine rate of change and also appropriate management if pre-eclampsia develops (GPP).
  
• Arrange a Doppler scan of the umbilical artery to assess fetal risk if onset of new hypertension is 36 completed weeks (B).
  

View this table: [in this window] [in a new window]   Table 3 Pregnancy specific ranges (calculated from 2 standard deviations above and below mean values) for serum uric acid by gestational age (µmol/l)10

 

Box 2 Liver function (gestation specific values, 95% reference ranges (2.5th centile to 97.5th centile)) in normal population11 and platelet count12 and creatinine concentration13 (pregnancy specific measures)    Liver function tests* Aspartate aminotransferase (IU/l) Non-pregnancy: 7-40 1st trimester: 10-28 2nd trimester: 11-29 3rd trimester: 11-30 Alanine aminotransferase (IU/l) Non-pregnancy: 0-40 1st trimester: 6-32 2nd trimester: 6-32 3rd trimester: 6-32    Pregnancy specific measures for platelet count and creatinine Platelet count: 150x109/l Creatinine: 90 µmol/l

Once the test results are available, do the following:

• Arrange medical review of abnormal blood test results or umbilical artery Doppler readings (GPP)
  
• Repeat step 1 assessments in one week if blood test results are normal; do not routinely repeat blood tests unless signs or symptoms change or routine repeat testing is recommended after medical review (D/GPP)
  
• Discuss the results and the plan for antenatal care with the woman (GPP).
  

For new proteinuria (no maternal symptoms or fetal compromise)
For 2+ proteinuria, do the following:

• Measure the platelet count; aspartate aminotransferase or alanine aminotransferase; serum creatinine; and serum urate (C). Use abnormal results for pregnancy specific ranges to diagnose partial HELLP syndrome, indicate underlying concurrent conditions, predict risk of poor maternal and/or fetal outcome, and establish a baseline for monitoring disease progression and predicting morbidity if pre-eclampsia does develop (C/D)
  
• Arrange a 24 hour urine collection to quantify proteinuria (C)
  
• Arrange a Doppler scan of the umbilical artery to assess fetal risk if proteinuria onset is 36 completed weeks (C)
  
• Arrange a medical review of abnormal or significant results (GPP).
  

For 1+ proteinuria, do the following:

• Exclude significant proteinuria by calculating the urinary protein to creatinine ratio from a random sample (C) or confirm and quantify by 24 hour urine collection (C). Use a threshold ratio of 30 to exclude significant proteinuria.¹⁴
  

For new hypertension and proteinuria

• Admit women with a diastolic blood pressure of 90 mm Hg and new proteinuria of 2+. (C)
  
• Admit women with a diastolic blood pressure of 110 and new proteinuria of 1+. (C)
  
• Arrange a medical review to consider admission of women with a diastolic blood pressure of 100-109 mm Hg and new proteinuria of 1+ (C)
  
• For women with diastolic blood pressure of 90-99 mm Hg and 1+ proteinuria, exclude significant proteinuria using the urinary protein creatinine ratio from a random sample (C) or confirm and quantify by 24 hour urine collection. (C)
  

Once the test results are available, do the following:

• Admit if significant proteinuria is confirmed or the protein creatinine ratio is 30 with new hypertension (C)
  
• Arrange a medical review of abnormal blood test results or Doppler readings. Discuss the results and the plan for antenatal care with the women. (GPP)
  

For transient new hypertension or new proteinuria

• Recheck women with no hypertension or proteinuria (after step 1) in the community within seven days. Women in this category are at higher risk of developing pre-eclampsia (51% subsequently develop hypertension or pre-eclampsia in the pregnancy).¹⁵ Refer back to the day assessment unit if signs or symptoms recur with community monitoring (PRECOG recommendations 4 and 5).⁶
  

Minimum standards
We recommend minimum standards for facilities and staff in any consultant led, hospital based day assessment unit,⁴ especially the following standards:

• Medical review requires specialty registrar ST3 or above (GPP)
  
• Allocate all women referred for further assessment to a named consultant (GPP)
  
• Offer written and verbal information so that women understand the purpose and outcome of the assessment at the day assessment unit. Women have a full and equal right to determine and be involved in their antenatal care. (GPP)
  

Overcoming barriers

Over 90% of day assessment units share staff with antenatal and labour wards and often have lower priority for staff.⁹ However, their remits have enlarged to include triage, management of labour, post-maturity assessment, and postnatal assessment. The pre-eclampsia assessments vary across these units, and equipment is often inadequate or poorly maintained.⁹ Errors have been implicated in maternal deaths.¹⁶ Minimum standards are essential for a cost effective service from day assessment units. Standardising assessments will be cost saving and preferred by women when unnecessary admission is avoided.¹⁷ Adoption, training, and implementation support is available via www.apec.org.uk.

Further information on the guidance National audit and resource implications We conducted a survey of all day assessment units in England, Wales, Scotland, and Northern Ireland in 2006. This provided information on the percentage of units currently conforming to the PRECOG guideline and on the national resource implications for implementation of the guideline.9 We found that most units have inadequate equipment. Some laboratory tests are routinely repeated unnecessarily. Nearly all units, however, have an infrastructure in place with a dedicated area and some permanent staff, and a 24 hour turnaround of laboratory tests. Half of the assessment units have access to portable Doppler facilities. Errors associated with inadequate equipment have been implicated in maternal deaths.16 Related resource implications (purchase and training) will depend on existing facilities. Overdiagnosis of pre-eclampsia with associated resource requirements of admission and treatment will be reduced when appropriate equipment is used. Standardising blood tests will be cost saving for nearly all units. Summary of methods This latest guideline is a follow-on guideline to the Pre-eclampsia Community Guideline published in 2005 under the auspices of the charity Action on Pre-eclampsia (APEC) using the same guideline development process and group.5 6 The recommendations have been developed by a multidisciplinary working group and graded according to the levels of evidence on which they were based.6 A record of the five PRECOG development group meetings at which this section of the PRECOG guideline was discussed is available from the APEC offices; the fourth meeting focused solely on these recommendations for day assessment units. Under the process of independent review an abstract of the guideline and evidence was accepted as an oral presentation at the International Society for the Study of Hypertension in Pregnancy meeting in 2006 and as a poster presentation at the Royal College of Midwives meeting, 2006. The guideline has been independently reviewed and submitted for peer review publication. A final meeting was held in November 2008. Minimum standards for facilities We recommend the following minimum standards for a consultant led, hospital based maternity day assessment unit (to provide rapid assessment, investigation, referral, and inpatient treatment): A dedicated area Midwifery staff specifically trained to work in and manage the day unit Easy access (either in the unit or close by) to facilities for Doppler scanning of the umbilical artery Access by the day unit staff to ST3 specialty registrars in obstetrics (or a higher grade) A system in which laboratory test results are available within 24 hours of the women attending, and the same day where practically possible, with a mechanism to review the tests and talk to the women concerned, also within 24 hours A named consultant to be part of the multidisciplinary team involved in the guidelines, protocols, and organisational running of the day unit The management and facilities in the day unit should be integrated into a larger protocol for the management of hypertension in pregnancy. Future research The systematic review of evidence has identified several research needs, including: The effectiveness of serum urate in predicting specific morbidity outcomes, in studies with strict population exclusion criteria and using thresholds of abnormality based on gestational age The effectiveness of readings from Doppler scanning of the umbilical artery in a population of women with new hypertension and no fetal compromise to identify fetal risk and predict poor fetal outcomes The value of Doppler scanning of umbilical artery to identify fetal risk in women at term.

Cite this as: BMJ 2009;339:b3129

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This is one of a series of BMJ summaries of new guidelines, which are based on the best available evidence; they highlight important recommendations for clinical practice, especially where uncertainty or controversy exists.

The members of the PRECOG development group comprised the authors of this summary plus the following: Janet Bray, medical writer; Julian Bradley, general practitioner; David Davies, obstetrician; Kirsten Duckitt, obstetrician; Michael de Swiet, obstetric physician; Deirdre Murphy, obstetrician; Vicki Osgood, obstetrician; and Sara Twaddle, health economist.

Contributors: All authors were involved in the conception, design, and content of the summary guideline, revised it critically for important intellectual content, and gave final approval of the version to be published.

Funding: Action on Pre-eclampsia is a self funded charity that provides information and support to women and healthcare professionals about pre-eclampsia. Funds are raised from donations and subscriptions, individual grants from the Department of Health and various foundations, and income from study and other education days, primarily for midwives. We received a grant from GlaxoSmithKline’s corporate department to support the development of this guideline. We also received some initial funding via Bayer for organisation of the first guideline development meeting in 2002. No member of the group was paid for their contribution, except for travel expenses to attend the various meetings. Neither funder had any involvement in the content or development of the guideline.

Competing interests: None declared.

Provenance and peer review: Not commissioned; not externally peer reviewed.

References

1. National Institute for Clinical Excellence, Scottish Executive Health Department, Department of Health, Social Services and Public Safety, Northern Ireland. Saving mothers’ lives; 2003-2005. The seventh report of the Confidential Enquiries into Maternal Deaths in the United Kingdom. London: CEMACH, 2007.
2. Bailey DJ, Walton SM. Routine investigations might be useful in pre-eclampsia, but not in gestational hypertension. Aust N Z J Obstet Gynaecol 2005;45:144-7.[CrossRef][Web of Science][Medline]
3. Saudan P, Brown MA, Buddle ML, Jones M. Does gestational hypertension become pre-eclampsia? Br J Obstet Gynaecol 1998;105:1177-84.[Web of Science][Medline]
4. PRECOG Development Group. Pre-eclampsia day assessment unit guideline for midwives (recommendations 9 and 10). 2009. www.apec.org.uk/pdf/precog/daug.pdf.
5. Milne F, Redman C, Walker J, Baker P, Bradley J, Cooper C, et al. The pre-eclampsia community guideline (PRECOG): how to screen for and detect onset of pre-eclampsia in the community. BMJ 2005;330:576-80.[Free Full Text]
6. PRECOG Development Group. Pre-eclampsia community guideline (PRECOG). 2004. www.apec.org.uk/pdf/Precog_complete.pdf.
7. Agency for HealthCare Policy and Research. Clinical practice guideline No 1: acute pain management: operative or medical procedures and trauma. Rockville, MD: US Department of Health and Human Services, 1993. (AHCPR publication No 92-0023.)
8. National Institute for Clinical Excellence. Antenatal care. Routine care of the healthy pregnant woman. (Clinical guideline 6.) 2003. http://guidance.nice.org.uk/CG6.
9. PRECOG Development Group. Evidence used to develop the pre-clampsia day assessment unit guideline (recommendations 9 and 10). 2009. www.apec.org.uk/pdf/precog/daue.pdf.
10. Lind T, Godfrey KA, Otun H, Philips PR. Changes in serum uric acid concentrations during normal pregnancy. Br J Obstet Gynaecol 1984;91:128-32.[Web of Science][Medline]
11. Girling JC, Dow E, Smith JH. Liver function tests in pre-eclampsia: importance of comparison with a reference range derived for normal pregnancy. Br J Obstet Gynaecol 1997;104: 246-50.
12. Tygart SG, McRoyan DK, Spinnato JA, McRoyan CJ, Kitay DZ. Longitudinal study of platelet indices during normal pregnancy. Am J Obstet Gynecol 1986;154:883-7.[Web of Science][Medline]
13. Girling JC. Re-evaluation of plasma creatinine concentration in normal pregnancy. J Obstet Gynaecol 2000;20:128-31.[CrossRef][Medline]
14. Price CP, Newall RG, Boyd JC. Use of protein-creatinine ratio measurements on random urine samples for prediction of significant proteinuria: a systematic review. Clin Chem 2005;51:1577-86.[Abstract/Free Full Text]
15. Anumba DOC, Lincoln K, Robson SC. Predictive value of clinical and laboratory indices at first assessment in women referred with suspected gestational hypertension. Hypertens Pregnancy (in press).
16. National Institute for Clinical Excellence, Scottish Executive Health Department, Department of Health, Social Services and Public Safety, Northern Ireland. Why mothers die; 2000-2002. The sixth report of the Confidential Enquiries into Maternal Deaths in the United Kingdom. London: CEMACH, 2004.
17. Twaddle S, Harper V. An economic evaluation of daycare in the management of hypertension in pregnancy. Br J Obstet Gynaecol 1992;99:459-63.[Web of Science][Medline]

(Accepted 21 July 2009)

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