Mean Arterial Pressure (MAP) and Pre-eclampsia

There is evidence that in a high proportion of pregnancies predisposed to develop pre-eclampsia the maternal mean arterial pressure (MAP) is increased at 11 to 13 weeks1. Combination of MAP with other markers facilitates a more effective method of screening for pre-eclampsia.

How to Measure Mean Arterial Pressure (MAP)

The blood pressure should be measured using automated devices, validated for pre-eclampsia (see list below).

DeviceModelValidation criteria*

OMRON

MIT Elite (HEM-7300-WE)

A/A2

Microlife

3BTOA-2

A/B3 or B/B4

Microlife

WatchBP Home

B/A5

Microlife

3AC1-1

B/A6

OMRON

M7 (HEM 780)

B/B7 or B/A8

GE Carescape

(Old name Dinamap ProCare 400)

A/B9

*Validation criteria recommended by British Hypertension Society (BHS). The device has to achieve a grade A or B for both SBP and DBP to be recommended for clinical use.

Positioning


  • The woman should be in a comfortable seated position with her arms supported at the level of the heart and legs uncrossed.
  • Cuff size should be selected depending on the mid-arm circumference.
  • Neither observer nor patient should talk for 5 min before or during the measurement.

Mean arterial pressure positioning

Measurement


  • The blood pressure (BP) should be measured in both arms simultaneously.
  • Series of recordings should be made at 1-minute intervals.
    • It is recommended10 to take the measurements until variations between consecutive readings fall within 10 mm Hg systolic (SBP) and 6 mm Hg in diastolic pressure (DBP) in both arms and then the last two measurements are used10.
    • Alternatively, the minimum of 2 readings can be used11.

How is The Mean Arterial Pressure (MAP) Calculated?

MAP is calculated from the systolic and diastolic readings:

MAP systolic and diastolic readings

References

  1. Poon LC et al. (2008) Mean arterial pressure at 11(+0) to 13(+6) weeks in the prediction of pre-eclampsia. Hypertension. 51(4):1027-33. Epub 2008 Feb 7. 
  2. Pregnancy Hypertension: Volume 2, Issue 4 , Pages 411-415, October 2012. Y. Chung, M.C. Brochut, A. de Greeff, A.H. Shennan. Clinical accuracy of inflationary oscillometry in pregnancy and pre-eclampsia: Omron-MIT Elite.
  3. Reinders A et al. (2005) An International Journal of Obstetrics & Gynaecology 112 : 915-920 An accurate automated blood pressure device for use in pregnancy and pre-eclampsia: the Microlife 3BTO-A. BJOG.
  4. Nouwen E, et al. Hypertens Pregnancy. 2012;31(1):131-9. doi: 10.3109/10641955.2010.544799. Epub 2011 Feb 18.Validation of the Omron M7 and Microlife 3BTO-A blood pressure measuring devices in pre-eclampsia.
  5. Chung Y, de Greeff A, Shennan A. Hypertens Pregnancy 2009;28:348-59.Validation and compliance of a home monitoring device in pregnancy: microlife WatchBP home.
  6. The Microlife 3AC1: An accurate blood pressure measurement device in pregnancy and pre-eclampsia. de Greeff A, Reggiori F, Anthony J, Shennan A. J Hypertens 2006;24.
  7. Blood Pressure Monitoring 2009, 14:37-40 Annnemarie de Greeff, Zara Beg, Zahra Gangji, Edwina Dorney and Andrew H. Shennan. Accurracy of inflationary versus deflationary oscillometry in pregnancy and pre-eclampsia: Omron-MIT versus Omron-M7.
  8. Nouwen E, et al. Hypertens Pregnancy. 2012;31(1):131-9. doi: 10.3109/10641955.2010.544799. Epub 2011 Feb 18.Validation of the Omron M7 and Microlife 3BTO-A blood pressure measuring devices in pre-eclampsia.
  9. Hypertens Pregnancy (2010)  29:198-205,210 Accuracy Assessment of the Dinamap ProCare 400 in Pregnancy and Pre-eclampsia. De Greeff et al.
  10. National Heart Foundation of Australia: Hypertension Management Guide for Doctors 2004.
  11. Protocol for measurement of mean arterial pressure at 11-13 weeks' gestation. Poon LC, Zymeri NA, Zamprakou A, Syngelaki A, Nicolaides KH. Fetal Diagn Ther. 2012;31(1):42-8.

 

PerkinElmer products for pre-eclampsia are not available in all countries. For information on availability please contact your local sales representative.

Information provided within the Overview of Pre-eclampsia is for information purposes only and not intended to be construed as medical guidance. Always contact your healthcare professional for assessment and direction regarding your health.