Causes of High Blood Pressure in Pregnant Women

Pregnant women may experience elevated blood pressure at any stage of their pregnancy. While the primary cause of hypertension during pregnancy is often unclear, several factors can increase the risk of developing this condition. These factors include:

Pre-existing high blood pressure before pregnancy.
Undergoing in vitro fertilization (IVF), commonly referred to as test-tube babies.
A history of hypertension in previous pregnancies.
Age; women under 20 or over 40 are at higher risk of hypertension during pregnancy.
Ethnicity; African American women are particularly prone to experiencing high blood pressure.
A previous incidence of preeclampsia in past pregnancies or a family history of the condition.
Obesity.
Carrying multiples, such as twins.
Having an autoimmune disease.
Other medical conditions, including lupus, diabetes, and kidney disease.
A history of gestational diabetes in prior pregnancies.

Types of Hypertension in Pregnant Women

There are various types of high blood pressure that can occur during pregnancy, some of which may predate the pregnancy, while others develop during it. Before delving into these types, it is important to clarify the term “white coat hypertension,” which refers to elevated blood pressure readings caused by anxiety related to clinical visits. It is common for blood pressure readings in a medical setting to be higher than those taken at home. Consequently, women experiencing this phenomenon are advised to measure their blood pressure at home and document the readings, enabling their healthcare provider to evaluate blood pressure measurements outside the clinical environment. Additionally, practicing relaxation techniques while waiting for medical appointments can be beneficial, especially when blood pressure is measured during these visits.

Chronic Hypertension

Chronic hypertension refers to high blood pressure that exists before pregnancy or is diagnosed before the 20th week of gestation. Women with this type of hypertension are at an increased risk of developing a condition known as preeclampsia, which will be discussed further below. It is crucial for women with chronic hypertension to inform their healthcare provider when planning or confirming a pregnancy, as this condition often presents without noticeable symptoms, making it difficult to identify its onset.

Concerning chronic hypertension, blood pressure readings are classified into four general categories:

Normal blood pressure: Defined as readings below 120/80 mmHg.
Elevated blood pressure: Considered elevated if systolic readings range from 120 to 129 mmHg, or diastolic readings are below 80 mmHg.
Stage 1 Hypertension: Characterized by systolic readings between 130-139 mmHg, or diastolic readings between 80-89 mmHg.
Stage 2 Hypertension: Defined as systolic readings above 140 mmHg, or diastolic readings exceeding 90 mmHg.

Gestational Hypertension

Gestational hypertension refers to the condition where blood pressure readings increase during pregnancy, diagnosed after the 20th week of gestation or around the time of delivery. This form of hypertension typically resolves following childbirth, with most cases improving within the first twelve weeks postpartum. Notably, gestational hypertension is not associated with the presence of protein in urine or complications affecting the kidneys or heart. However, women with this condition are at a higher risk of developing chronic hypertension in the future, and in some instances, it may progress to preeclampsia. Symptoms can vary between pregnancies, and some women may exhibit no symptoms at all; elevated blood pressure readings may be the only indication of gestational hypertension. Importantly, this condition may not adversely affect the mother or baby if properly monitored and managed.

Gestational hypertension can be categorized into three classes:

Mild hypertension: Classified when systolic readings are between 140 and 149 mmHg, and diastolic readings range from 90 to 99 mmHg.
Moderate hypertension: Defined by systolic readings between 150 and 159 mmHg, with diastolic readings from 100 to 110 mmHg.
Severe hypertension: Characterized by systolic readings exceeding 160 mmHg, and diastolic readings above 110 mmHg.

Preeclampsia

Preeclampsia, also referred to as pregnancy-induced hypertension, occurs after the 20th week of pregnancy among women who had normal blood pressure prior to pregnancy. It is characterized by a sudden rise in blood pressure, along with signs of acute damage to organs such as the kidneys or liver. If properly managed, it is not typically hazardous to either the mother or the baby. Symptoms of preeclampsia may not always be present, making regular check-ups essential for early detection, even in the absence of symptoms. In rare cases, symptoms may emerge post-delivery, a condition known as postpartum preeclampsia, which can manifest within 48 hours to six weeks after childbirth. Potential symptoms include:

Persistent headaches.
Nausea and vomiting.
Visual disturbances, such as blurred vision.
Sudden weight gain beyond normal limits for pregnancy.
Swelling of the face and hands.
Respiratory issues.
Pain in the upper abdomen.

Preeclampsia may escalate to a more severe condition known as eclampsia, which involves grand mal seizures or unexplained coma, occurring after the 20th week of pregnancy or in the postpartum period. Notably, some eclampsia cases have been documented without any previous reports of high blood pressure or proteinuria.

Managing High Blood Pressure in Pregnant Women

To ensure the health and safety of pregnant women facing hypertension, several recommendations should be followed:

Adopt a healthy diet, including a reduction in added salt intake.
Maintain physical activity by engaging in walking or swimming, upon consultation with a healthcare provider, as complete rest may be necessary for some cases.
Cease smoking and avoid alcohol consumption.
Monitor weight gain to stay within recommended limits during pregnancy.
Adhere to prescribed medication schedules and dosages as advised by healthcare providers.
Attend regular medical check-ups and monitor blood pressure readings at home.
Avoid stress and excessive strain.

References:

(*) Lupus: A disease resulting from the immune system attacking the body’s connective tissues, including joints, skin, brain, kidneys, and other parts.

(*) Gestational Diabetes: A condition characterized by elevated blood sugar levels during pregnancy sufficient to diagnose diabetes.

(*) In Vitro Fertilization (IVF): A technique used to assist individuals facing fertility issues by fertilizing an egg with sperm in a laboratory before transferring the embryo to the mother’s womb.