What happens to blood pressure in pregnancy

The normal tendency is for the blood pressure to fall slightly during pregnancy. It may reach a nadir about halfway through, at around 18-20 weeks of gestation. It tends to stay there, more or less. It may then rise back towards the pre-pregnancy levels towards the end of the pregnancy. That is the experience of the majority of pregnant women.

Falling blood pressure in pregnancy

A dangerous fall in blood pressure during pregnancy is extremely unusual and this possibility can be safely ignored.

Occasionally, women may experience light-headedness and feeling faint during pregnancy. This tends to occur on prolonged standing, walking in the sun or rising rapidly from a sitting position.

Actual blackouts are also reported occasionally. This is quite uncommon.

For a woman who is prone to any of the above, the sensible thing is to avoid the precipitating factors. It is also important to take the common sense measures to avoiding risky situations such as walking alone in places with heavy motor traffic. It is usually an unnecessary overkill for the mother to put restrictive limits to her activities, just because she has had the odd feeling of faintness in pregnancy.

As a rule, the fall in blood pressure is temporary and lasts a few seconds before the self-regulatory mechanisms kick in to correct it. Feeling light-headed should never be an overriding worry.

Raised blood pressure (hypertension) in pregnancy

This is a problem.

There is no point in any doctor or midwife trying to say "not to worry" when a mother is noted to have raised blood pressure in pregnancy. The action that is taken is the important issue for the expectant mother to concentrate upon.

Types of hypertension (in pregnancy)

There are two broad groups. These are:

· Pre-existing hypertension

· Pregnancy-induced hypertension

Pre-existing hypertension can also be termed "chronic hypertension" or, when the cause is unknown (as is mostly the case), "essential hypertension". If you happen to suffer from hypertension, you will encounter these terms many times.

Pregnancy-induced hypertension is more commonly known as pre-eclampsia and was also once known as "toxemia of pregnancy", "pre-eclamptic toxemia" (PET) and in North America "EPH gestosis". These terms may crop up occasionally but they are largely historical now.

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