High Blood Pressure during pregnancy.

What is the difference between chronic high blood pressure and gestational hypertension?

Sometimes it's hard to know whether you have chronic high blood pressure or gestational hypertension until after you deliver your baby. If you have high blood pressure before you're 20 weeks pregnant, it usually means you have chronic high blood pressure. This is a long-term type of high blood pressure that affects up to 5 percent of pregnant women.

Gestational hypertension – also called pregnancy-induced hypertension – is high blood pressure that usually occurs for the first time at 20 weeks of pregnancy or later. Gestational hypertension is temporary and almost always goes away after childbirth.

What are the risk factors for chronic high blood pressure?

The risk factors that make chronic high blood pressure more likely include:

Age (The older you are, the higher the risk.), Having a family history of high blood pressure, Being African American, Having diabetes or kidney disease, Having or had pre-eclampsia in a previous pregnancy, Being overweight, Eating too much salt, Poor nutrition, especially a diet that lacks fruits and vegetables.

Some risk factors can't be changed, such as your genes or having certain health conditions. But you can make changes to reduce other risk factors, and these are important to know about when you're trying to get pregnant.

How is high blood pressure diagnosed?

You'll have your blood pressure measured at each appointment during pregnancy. Your healthcare provider may also ask you to monitor your blood pressure at home.

High blood pressure is diagnosed when either or both the systolic or diastolic blood pressure is at an unhealthy level. Because blood pressure varies throughout the day, your provider may take several readings at different times.

A blood pressure reading of:

Less than 120/80 is considered healthy blood pressure (normal).

At least 120/80 but less than 140/90 is considered at risk for high blood pressure (prehypertension).

At least 140/90 but less than 160/110 is mild high blood pressure (mild hypertension)160/110 and above is severe high blood pressure (severe hypertension)

How does high blood pressure affect pregnancy?

Many women with mild high blood pressure have a normal pregnancy. Blood pressure typically falls slightly early in pregnancy and then returns to pre-pregnancy levels in the third trimester.

But the more severe high blood pressure is during pregnancy, the greater the risk of problems. There's also a greater risk of complications if you've had high blood pressure for a long time and it's damaged your heart, kidneys, or other organs. The risks are also higher for women with high blood pressure that's caused by another medical condition, such as diabetes or kidney disease.

High blood pressure risks include:

Preeclampsia: If high blood pressure develops after 20 weeks of pregnancy and you have protein in your urine, or if there are signs that certain organs aren't working properly (like your liver), this could signal a serious condition called preeclampsia. Preeclampsia that develops when you already have high blood pressure is called "superimposed preeclampsia." Between 13 and 40 percent of women with high blood pressure develop superimposed preeclampsia during pregnancy.Having a baby that's smaller than normal: High blood pressure can mean that your baby doesn't get all the necessary nutrients and grows more slowly than usual (intrauterine growth restriction or IUGR). The risk of a baby being born small depends on how severe your high blood pressure is and whether you have other complications, like anemia or kidney disease.Cesarean birth: Women with high blood pressure are at a higher risk of delivering by cesarean section (c-section), which is surgery that can lead to other complications. On average, about 4 out of 10 women with high blood pressure give birth by c-section.Placental abruption: In this condition, part or all of the placenta separates from the uterine wall before the baby is born. There are different degrees of placental abruption, and in severe cases, a baby may not get enough oxygen and need to be born right away. If high blood pressure is mild, the risk of placental abruption is low, affecting about 1 in 100 women. If high blood pressure is severe or preeclampsia develops, the risk increases to range from 5 to 10 percent.Preterm birth: If complications develop, or it looks like your baby isn't growing well, it may be necessary to deliver early. The more severe high blood pressure is, the more likely it is to need an early delivery. On average, 28 percent of women with high blood pressure have their baby before they're 37 weeks pregnant. Studies show between 62 and 70 percent of women with severe high blood pressure deliver early.