Healthy blood pressure

Normal blood pressure stays between 90/60 mmHg (you say this aloud as 'ninety over sixty millimetres of mercury',) and below 140/90 mmHg ('one hundred and forty over ninety millimetres of mercury'). It does not go up much during pregnancy.

Warning signs

High blood pressure is known as hypertension and is a warning sign. The woman has high blood pressure if either of these is true:

The top number is 140 or above.
The bottom number is 90 or above.

Very low blood pressure is also a warning sign, which is usually caused only by heavy bleeding or shock (a dangerous reduction in blood flow throughout the body). This is a very dangerous situation:

The top number is less than 90
The bottom number is less than 50

It is very important to check the mother's blood pressure at every antenatal visit. A woman with very high or very low blood pressure should be referred to the nearest higher health facility immediately