High blood pressure and pregnancy

The existence of a high blood pressure during the pregnancy represents a real danger for the mother and the child, because it is integrated in a disease that the physicians call "pre-eclampsia" or "eclampsia" according to the stage. This disease is in fact an immunological disease responsible for damage of the kidney, brain, liver, placenta, cardiovascular system and hormonal system.

This disease appears during the third quarter of a first pregnancy and disappears just after the childbirth. It endangers the life of the mother and her baby, and often causes premature births.

The symptoms are characterized by diffuse oedemas (due to a renal insufficiency), a high blood pressure which can be very high, disorders of the nervous system which are associated with a reduction of the sight, violent headaches (due to an oedema or to bleedings in the brain).

Many researchers around the world have studied «Eclampsia», and three hypotheses are currently retained: this disease comes from the placenta; it comes from the mother and especially from her environment; or this is a purely genetic disease of the mother. But these are only hypotheses and research is currently in hand.

We know that this disease corresponds to a disorder state of the immune system, but its exact cause is now unknown.

The kidney: development of a renal insufficiency and of diffuse oedemas;
The brain: development of an oedema and of bleedings in the brain;
The liver: possible development of a liver insufficiency;
The placenta, which can be detached from the uterus and induce the death of the baby.

8.3.4- What the physician do in case of eclampsia or high blood pressure during the pregnancy?

Initially, he suspects the diagnosis of eclampsia in case of a high blood pressure, especially if it minimal (diastolic) is higher than 100 millimetres of mercury (10). Then, the diagnosis is confirmed by a high protein concentration in the urine.

Then, an antihypertensive drug therapy is prescribed, but in a very careful way so that the blood pressure does not drop too quickly because the blood flow would be severely reduced in the placenta.

When the birth is imminent, the practitioner gives antihypertensive drugs by intravenous way, but if the birth is not imminent then tablets are prescribed so as to delay the birth as much as possible.

What does the physician in case of a high blood pressure already existing before the pregnancy?

The majority of women who have high blood pressure before the pregnancy will slightly increase the value of their blood pressure and the cardiovascular risk is thus weak. In general, the blood pressure will naturally decrease during the second quarter of the pregnancy, because of a expansion of the peripheral arteries. Thus, the antihypertensive drug therapy can be stopped on this occasion, under strict medical supervision.

When the diastolic blood pressure (the minimal one) drops below 90 millimetres of mercury (9), the antihypertensive drug therapy can be reduced.

In this case, no medical study has proved the real effectiveness of an antihypertensive drug therapy on the cardiovascular complications.

To avoid high blood pressure, it is of primary importance to respect life style modifications: that is, the reduction of sodium intake and of high calorie meals. On the other hand, it is not recommended during this period to lose weight or to practise physical exercise.

The practice of self-measurement of the blood pressure at home seems to be a very good way to prevent cardiovascular complications.

If antihypertensive drugs must be used, the practitioner must be careful and ensure of the absence of toxicity on the child. The safer antihypertensive drugs are beta-blockers firstly and the calcium-channel antagonists, secondly. All the other antihypertensive drugs must be avoided.