Hypertension and Pregnancy - Pre eclampsia
Hypertension maybe associated with pregnancy in two forms; chronic hypertension and pregnancy induced hypertension also known as toxemia of pregnancy or pre-eclampsia.
Chronic hypertension is the traditionally known type of hypertension with elevation of diastolic and/or systolic blood pressure for a considerably long period of time at least starting before pregnancy or before its 20th week. The exact etiology of this condition is still unknown and is thought to be a combination of genetic predisposition, diet, lifestyle and many other factors.
It carries many risks when involved with pregnancy such as; premature delivery, fetal deprivation of oxygen due to narrowing of the maternal blood vessels, a condition known as abruptio placentae or premature separation of the placenta which carries the risk of severe bleeding for the mother and oxygen deprivation for the fetus and hypertension during pregnancy may also lead to a heart attack in the mother.
Usually, with the proper prenatal care, no serious complications will occur. Some anti-hypertensives normally used for treatment of conditions of chronic hypertension may carry a risk of being teratogenic, meaning that they may induce mutations and deformities in the fetus. These drugs should be avoided or replaced with other drugs during the period of gestation.
Pregnancy induced hypertension (PIH) which is also known as toxemia of pregnancy or pre-eclampsia is a completely different matter. It is a condition where there is elevation of the blood pressure that begins during pregnancy. It affects an estimated one out of ten of all pregnancies, most likely affecting young women.
Predisposing factors that increase the risk of developing pre-eclampsia in an expectant mother include the following:
- First time mothers.
- Pregnancies in women over 40 years of age.
- History of pre-eclampsia in previous pregnancies.
- Family history of pre-eclampsia.
- Pregnant women suffering from renal diseases (diseases involving the kidney).
- Carrying twins or other types of multiples pregnancies.
- Mothers with long intervals exceeding ten years between pregnancies
- Pre-existing conditions of chronic hypertension.
- Pre-existing diabetes mellitus.
- Obesity.
- Anti-phospholipid antibody syndrome which is a condition characterized by increased coagulability of the blood causing an increased risk of thrombi and emboli (or blood clots causing obstruction of blood vessels). It is associated with systemic lupus erythematosus (SLE) and can be a cause of repeated miscarriages.
The cause of this condition being named pre-eclampsia, is that it develops over a period of weeks before finally reaching a stage of severe symptoms known as eclampsia. Eclampsia is a condition that occurs towards the end of pregnancies where a pregnant woman actually develops seizures due to pregnancy induced hypertension.
However, progression to this severe stage is fortunately, not very common.
Criteria used to detect the presence of pre-eclampsia usually considered are; elevation of blood pressure above 140/90 mmHg (where normal blood pressure ranges between (90-130/60-85) or a significant elevation of one or both blood pressures compared to patient’s norm, presence of protein in urine and significant edema (even though edema may occur normally during pregnancy).
If diagnosed with pre-eclampsia, the only way to cure it is to deliver the baby. It is generally preferable to delay delivery for as long as possible, provided that the mother’s blood pressure is stabilized. If it’s possible to delay delivery until natural labor occurs, that’s a better option than opting for a cesarean section to deliver the baby early.
However, if the baby must be delivered much earlier than the expected date of labor sometimes even immediately due to the severity of the condition, a cesarean section may be necessary. The mother will then be given steroid injections one to two days before the date of the c-section in order to minimize the risk of lung complications associated with pre-maturity. This is because steroids induce the growth of a material known as the lung surfactant which is necessary for normal respiratory functions and reduce the risk of neonatal respiratory distress.