At the first sign of high
blood pressure during pregnancy, your health professional cannot predict
whether it will remain mild, become severe, or turn out to be an early sign of
preeclampsia. If you are developing preeclampsia, your
urine test (urine screen) will probably show increased protein levels before
long. This sign that your kidneys are being affected by the condition doesn't
develop right away.
If you aren't certain that you had normal
blood pressure before pregnancy, it is possible that you have preexisting
chronic high blood pressure. If so, your blood pressure may remain high after
High blood pressure that develops during pregnancy
High blood pressure that develops before the 20th week
of pregnancy is usually a sign of ongoing (chronic) high blood pressure or
short-term, mild high blood pressure. In rare cases, it is an early sign of
High blood pressure that
occurs after midpregnancy could be a sign that you are developing preeclampsia.
This can be anytime after the 20th week.
Chronic high blood pressure and pregnancy
with chronic high blood pressure (hypertension) who become
pregnant normally have a drop in blood pressure during the first two
trimesters. During the late second or in the third trimester, however, blood
pressure returns to higher-than-normal levels. Following delivery, their blood
pressure remains high. For more information, see the topic High Blood Pressure.
Chronic high blood pressure increases your risk
of preeclampsia during pregnancy.
Most women with chronic high
blood pressure who are otherwise healthy have a low risk for other
cardiovascular problems during pregnancy.
Women with chronic high blood pressure have an increased
risk of the premature separation of the placenta from the uterine wall (placenta abruptio). This risk may increase when:
- A mother smokes during
- Preeclampsia develops in addition to chronic high blood
- A mother uses certain drugs, such as cocaine.
is an injury to the uterus, such as in a car accident or a fall.
Preeclampsia affects your blood
kidneys, and brain. Preeclampsia can be mild or
severe, and it may get worse gradually or rapidly. Both you and your fetus can
potentially suffer life-threatening problems involving the following:
- Blood pressure. Blood
volume doesn't increase as much as it should during pregnancy. This can affect
fetal growth and well-being. The blood vessels also increase their resistance
against blood flow (vasospasm), increasing blood pressure.
- Placenta. The blood vessels of the placenta don't grow deep
into the uterus as they should, nor do they widen as they normally would. This
makes them unable to provide normal blood flow to the fetus.
- Liver. Impaired blood circulation to the liver can cause liver
damage. Liver impairment is related to the life-threatening
HELLP syndrome, which requires emergency medical treatment.
- Kidneys. During a normal pregnancy,
function increases by up to 50%.2 When affected by
preeclampsia, kidney function is usually higher than before pregnancy but not
as high as necessary for a healthy pregnancy. This is called mild renal
- Brain.Vision impairment,
persistent headaches, and seizures (eclampsia) can develop, probably in
relation to reduced blood flow to or within the brain. Less than 1% of women
who have preeclampsia suffer one or more seizures.3
Eclampsia can lead to maternal coma and fetal and maternal death. This is why
women with preeclampsia are often given medicine to prevent
- Blood. Low
platelet levels in the blood are common with
preeclampsia. In rare cases a potentially life-threatening blood-clotting and
bleeding problem develops along with severe preeclampsia.4 This condition is called disseminated intravascular
coagulation (DIC). After delivery, DIC goes away. In the meantime, you may be
given a medicine (clotting factor), blood transfusion, or platelet transfusion.