Hypertension in Pregnancy

One of common medical problems encounter during pregnancy is hypertension, which complicates 2-3 percent of pregnancies. Hypertension in pregnancy may cause maternal morbidity (including eclamptic seizures, intracerebral hemorrhage, pulmonary edema, acute renal failure, and disseminated intravascular coagulation) and fetal morbidity (including intrauterine fetal growth retardation, intrauterine fetal death, abruptio placentae, and premature delivery). It also remains a leading source of maternal mortality.

Hypertensive disorders during pregnancy can be classified into 4 categories:

1. Chronic hypertension: hypertension (blood pressure exceeding 140/90 mmHg in the sitting position; after sitting quietly for 5-10 minutes before each blood pressure measurement) has been diagnosed before pregnancy or before 20 weeks of gestation.

2. Preeclampsia-eclampsia: new onset of elevated blood pressure after 20 weeks of gestation, concomitant with rapid weight gain due to edema and laboratory finding of protein in the urine (proteinuria). Eclampsia: the same as preeclampsia with occurrence of seizures

3. Preeclampsia superimposed on chronic hypertension: preeclampsia which happens in pregnancy woman with pre-existing hypertension

4. Gestational hypertension: transient hypertension of pregnancy occurring in late pregnancy without any other features of preeclampsia, with normalization of blood pressure postpartum. Transient hypertension is associated with later life development of chronic hypertension.

Preeclampsia occurs in approximately 5% of all pregnancy, 10% of first pregnancies, and 20-25% of pregnant women with history of chronic hypertension. Maternal personal risk factors of preeclampsia to include first pregnancy, new partner/ paternity, age younger than 18 years old or older than 35 years old, history of preeclampsia, family history of preeclampsia in a first-degree relative, obesity, and inter-pregnancy interval less than 2 years or more than 10 years.

Preeclampsia is primarily a disorder of endothelial function of vasculature with associated vasospasm. Altered maternal immune response to fetal/ placental tissue may also contribute to the development of preeclampsia. Endothelial damage not only leads to diffuse microthrombosis of placenta that cause abnormal placental development or placental damage, but also leads to multiple organ dysfunctions and pathologic capillary leak which manifest in the mother as rapid weigh gain, edema (sudden worsening of lower extremity edema, edema of hands and face), pulmonary edema, and/ or hemoconcentration (hemoglobin levels greater than 13 g/dL). Abnormal placenta due to diffuse microthrombosis will decrease utero-placental blood flow which affects the fetus and can be manifest clinically as intrauterine fetal growth retardation and oligohydramnios.

Based on those have stated above, antenatal care is very important in all pregnancies to identify hypertension in pregnancy and get prompt treatment. Moreover, women with hypertension during pregnancy require postpartum medical follow up.