Mean Arterial Pressure Calculator in Pregnancy

Instructions and clinical scope

Enter systolic and diastolic blood pressure. Results update automatically. This tool calculates mean arterial pressure (MAP) and provides obstetric blood pressure prompts. MAP is not a diagnostic substitute for pregnancy hypertension criteria, repeated properly measured blood pressures, symptom assessment, laboratory evaluation, or local protocols.

Blood pressure entry

Systolic BP, mm Hg

Diastolic BP, mm Hg

Heart rate, bpm optional

Gestational age, weeks optional

Days

Clinical setting

Repeat reading status

Symptoms concerning for preeclampsia or severe disease: headache, visual symptoms, RUQ/epigastric pain, dyspnea, chest pain, neurologic symptoms

Known or suspected hypertensive disorder of pregnancy

Manual BP or validated device used, appropriate cuff size, patient rested and positioned

Optional serial MAP trend

Optional fields for a prior or comparison blood pressure. Useful for bedside trend review or home BP logs.

Prior systolic BP, mm Hg

Prior diastolic BP, mm Hg

Prior label

Measurement reminders

Use a properly sized cuff on a supported bare arm at heart level.
Have the patient seated or in an appropriate lateral position, rested, and not talking during measurement when feasible.
Repeat elevated readings according to local obstetric hypertension protocol.
Do not use MAP alone to diagnose or exclude gestational hypertension, preeclampsia, or severe-range hypertension.

Equations and interpretation

Standard MAP equation

MAP = DBP + 1/3 x (SBP - DBP) Equivalent: MAP = (SBP + 2 x DBP) / 3

This is a practical estimate from brachial systolic and diastolic blood pressure. It assumes that approximately one-third of the cardiac cycle is systole and two-thirds is diastole.

Optional heart-rate adjusted estimate

If heart rate is entered: Systolic fraction = 0.01 x exp(4.14 - 40.74 / HR) HR-adjusted MAP = DBP + systolic fraction x (SBP - DBP)

The heart-rate adjusted estimate is included as a comparison only. The standard formula is the default clinical display.

Pregnancy blood pressure guardrails

Finding	Prompt
SBP 140-159 or DBP 90-109 mm Hg	Elevated in pregnancy. Repeat and evaluate according to gestational age, symptoms, prior BP, proteinuria, labs, and local protocol.
SBP at least 160 or DBP at least 110 mm Hg	Severe-range BP. Confirm promptly and manage urgently according to obstetric severe hypertension protocol.
MAP	Useful for hemodynamic summary and trends, but not a stand-alone diagnostic criterion for hypertensive disorders of pregnancy.

References

Mean arterial pressure formula: MAP = (SBP + 2 x DBP) / 3. MDCalc. Mean Arterial Pressure Calculator.
Razminia M, Trivedi A, Molnar J, et al. Validation of a new formula for mean arterial pressure calculation: the new formula is superior to the standard formula. Catheter Cardiovasc Interv. 2004;63(4):419-425. PubMed.
American College of Obstetricians and Gynecologists. Preeclampsia and High Blood Pressure During Pregnancy. ACOG FAQ.
American College of Obstetricians and Gynecologists. Clinical Guidance for the Integration of the Findings of the Chronic Hypertension and Pregnancy Trial. ACOG Practice Advisory.
Magee LA, Brown MA, Hall DR, et al. The 2021 International Society for the Study of Hypertension in Pregnancy classification, diagnosis and management recommendations for international practice. Pregnancy Hypertens. 2022;27:148-169. PubMed.
Garovic VD, Dechend R, Easterling T, et al. Hypertension in pregnancy: diagnosis, blood pressure goals, and pharmacotherapy. Hypertension. 2022;79(2):e21-e41. Free full text.