Hypertension and Pregnancy

Ever since Lady Sybil died on Downton Abbey, there’s been more talk than usual about high blood pressure (AKA hypertension) and pregnancy.

And in some of the reporting, there’s been a bit of confusion. Since this month is all about the heart, we figure it’s a great time to clear things up. The truth is that while approximately 5% of all pregnancies are affected by hypertension, not all mothers will develop serious complications.

Hypertension/high blood pressure is defined as blood pressure that’s 140/90 or higher on two or more occasions. If either number is higher than those stated, even if the other number is normal, it indicates high blood pressure. For example, 140/80 and 120/90 are both high. Sometimes, people have a single high blood pressure reading due to stress, medication or other factors. When blood pressure is consistently high under varying conditions, that’s when hypertension is diagnosed. It’s usually successfully treated with medication, improved diet, weight loss, exercise, and stress reduction and by quitting smoking.

High blood pressure during pregnancy can reduce blood flow to the placenta, which restricts oxygen and nutrient delivery to the baby. It can also increase the workload on the mother’s heart and other vital organs and lead to heart attack and stroke. If hypertension is controlled and monitored during prenatal care, her chances for a healthy pregnancy and baby are great.

Hypertension is the most common medical problem encountered during pregnancy and is generally sorted into four categories:

1) Chronic hypertension — The American Congress of Obstetricians and Gynecologists defines chronic hypertension in pregnancy as hypertension present before pregnancy or before the 20th week of gestation. The mother may or may not need to take medication to normalize her blood pressure, depending on whether her condition is mild, moderate or severe. All women with hypertension are strongly encouraged to monitor their weight and exercise regularly to help normalize blood pressure.

2) Gestational hypertension (AKA pregnancy-induced hypertension or PIH) is high blood pressure that first occurs during the second half of pregnancy. It usually returns to normal after birth. It might be treated with medication, bed rest or simply be monitored. Whenever blood pressure rises during pregnancy, lab work is needed make sure the woman isn’t developing pre-eclampsia or eclampsia. While hypertension does not cause preeclampsia/eclampsia, it is a clinical sign.

3) Preeclampsia/Eclampsia — Preeclampsia is a serious medical condition affecting all organs of the body. Approximately 5–8% of all pregnant women get preeclampsia. High blood pressure is one of its most common signs. Because preeclampsia causes stress on the kidneys and reduces their ability to filter urine, protein in the urine is another significant indicator.

If the woman also develops seizures she is then diagnosed with eclampsia. Sometimes seizures are the first and only symptom a woman develops, though usually preeclampsia/eclampsia are accompanied by other symptoms, including:

• Headaches
• Visual problems
• Rapid weight gain
• Swelling of the hands, feet and face
• Upper abdominal pain

Nobody knows exactly what causes preeclampsia, but the most important factors currently being considered are:

• Maternal immunologic intolerance
• Abnormal placental implantation
• Genetic, nutritional, and environmental factors
• Cardiovascular and inflammatory changes

Though we don’t know why women get preeclampsia, we do know that some are at higher risk than others, including women who

• Are pregnant for the first time
• Had preeclampsia in a previous pregnancy
• Have chronic hypertension
• Are 35 years or older
• Are carrying more than one fetus
• Have diabetes or kidney disease
• Are obese
• Are African American
• Have immune disorders, like lupus, or blood diseases

Severe preeclampsia/eclampsia can cause organ damage to the brain, kidneys, liver, eyes, and heart, can result in death and is a leading cause of maternal mortality. When women develop preeclampsia in developed countries, they’re usually hospitalized and receive medications to reduce her blood pressure and prevent seizures. One of the most important advances in the treatment of preeclampsia/eclampsia is magnesium sulfate, a mineral infused through an IV to relax smooth muscle tissue and prevent seizures. That’s why fewer women die now than they did in “the olden days,” and why fewer women die in developed countries than in undeveloped countries with limited access to healthcare.

The only way to cure preeclampsia is to deliver the baby and end the pregnancy, though it can persist postpartum for a few days, even a few weeks. That decision is made based on the severity of the mothers condition, how well she responds to treatment and her baby’s maturity and development. If the baby won’t be born soon, the mother might receive magnesium sulfate for several days or weeks so she can tolerate pregnancy and give her baby time to develop. If the baby must be delivered to save mom’s health and she’s not in labor, she’ll need to be induced or have a C-section.

About 10–20% of women with severe preeclampsia/eclampsia develop a condition called HELLP Syndrome, which stands for Hemolysis (breakdown of red blood cells), Elevated Liver enzymes, Low Platelet count. This can cause hemorrhage, pulmonary edema, kidney failure and placental abruption. The main treatment is immediate delivery, even if the baby is premature. The mother may also need blood transfusions. HELLP syndrome usually goes away after delivery.

4) Preeclampsia superimposed on chronic hypertension occurs in women with chronic hypertension before pregnancy who then develop worsening high blood pressure and protein in the urine during pregnancy. It’s estimated that 25% of women with chronic hypertension may go on to develop preeclampsia. When chronic hypertension is medically managed and the pregnancy is well monitored, however, women and their babies do well.

Hypertension is prevalent in all cultures, races and socioeconomic backgrounds. It’s particularly prevalent in African American and black communities, which may partly account for why maternal mortality rates are four times higher in African American women than women of other races. The key to survival lies in medical treatment, lifestyle changes and research to find causes and cures. Without access to healthcare, mothers and babies will continue to die from hypertensive disorders we now know how to manage. And if Sybil had been alive today, she probably would have survived her birth.

More information about preeclampsia can be found at www.preeclampsia.org.

(Picture: Nick Briggs/BBC)