The information provided below is for readers based in the United States of America. Readers outside of the United States of America should seek the information from local sources.

What is preeclampsia in pregnancy?

Preeclampsia is a condition that can develop during pregnancy, after 20 weeks of gestation, or after delivery. The condition is characterized by the emergence of high blood pressure (more than 140 mm Hg systolic, or more than 90 mm Hg diastolic), along with kidney problems that cause proteinuria (protein in the urine at levels higher than 300 mg per 24 hours) or problems with other organs. Any preeclampsia should be viewed as a severe condition, but the high blood pressure element of preeclampsia is defined as severe if the systolic pressure climbs higher than 160 mm Hg, or the diastolic pressure climbs higher than 110 mmHg.

The current classification system makes preeclampsia one of several blood pressure conditions that can occur during or just after pregnancy, but there is some overlap between the various conditions.

How common is preeclampsia during pregnancy?

Preeclampsia develops in 2 10 percent of pregnancies. Factors that increase the risk of developing preeclampsia include high maternal age (greater than 35 years), history of preeclampsia in the family, preeclampsia in a previous pregnancy, obesity (high body mass index), nulliparity (you have never given birth before), high blood pressure prior to pregnancy (chronic hypertension), type 1 diabetes, multiple fetuses (twin or higher pregnancy), systemic lupus erythematosus (SLE, lupus), kidney disease, a condition called antiphospholipid antibody syndrome, and in non-Asians carrying a male baby.

How is preeclampsia during pregnancy diagnosed?

To qualify as preeclampsia, blood pressure in the range of 140 – 160 mmHg systolic or 90 -110 mmHg diastolic must be recorded on two separate readings, taken at least 4 hours apart, and must be new for the patient (as opposed to continuation of a pre-pregnancy or early pregnancy high blood pressure condition), and must be accompanied by some trouble with organs or platelets. However, there does not need to be protein in the urine.  Also, very importantly, if the patients blood pressure measures in the severe range (>160 systolic, >110 diastolic), physicians are not supposed to wait the 4 hours to take a second reading, nor does there need to be any evidence of an organ problem. Rather, the condition is assumed to be preeclampsia and is treated accordingly.

To support the diagnosis, doctors will test urine samples for protein and will perform blood tests aimed at evaluating the function of organs, such as the kidneys and liver. A complete blood count also will be performed to evaluate for anemia and a low platelet count and for a test called a blood smear which can reveal broken red blood cells. The level of oxygen in your blood will be tested and the developing baby will be monitored with ultrasonography. If a clot or bleeding in the brain is suspected, brain imaging will be obtained with magnetic resonance imaging (MRI) or computed tomography (CT).

Does preeclampsia cause problems during pregnancy?

Preeclampsia can lead to a hemorrhagic stroke (bleeding in the brain), particularly if it is preeclampsia with high blood pressure in the severe range (systolic above 160 mmHg or diastolic above 110 mmHg). Stroke also can develop, due to a clot in the brain (ischemic stroke). Preeclampsia can develop into a more severe condition called eclampsia, which is defined by the onset of seizures in a patient who already has preeclampsia. Preeclampsia also can evolve into a condition called HELLP syndrome. This is a condition that also can exist separately from preeclampsia, but in either case, it is characterized by red blood cells breaking apart (hemolysis) and the number of platelets (clot-forming cells) in blood dropping down, leaving the woman prone to hemorrhage (severe bleeding). If preeclampsia includes the severe range of high blood pressure (called preeclampsia with severe features), or if eclampsia develops, numerous other complications can develop in the brain, retina of the eye, and liver, and the placenta can detach prematurely from the uterus (abruptio placentae).

Does preeclampsia during pregnancy cause problems for the baby?

Along with causing bleeding that endangers the mother, abruptio placentae (detachment of the placenta from the uterus) can lead to the death of the baby. With or without abruptio placentae, preeclampsia can cause premature birth, restrict the developing baby’s grown, or lead to stillbirth or death soon after birth.

Preeclampsia with severe high blood pressure, or the development of eclampsia, can lead to additional complications, such as blood clotting problems, kidney failure, various problems in the lungs requiring a ventilator, complications in the blood vessels of the brain, and high risk of maternal death.

What to consider about taking medications when you are pregnant or breastfeeding:

  • The risks to yourself and your baby if you do not treat the preeclampsia
  • The risks and benefits of each medication you use when you are pregnant
  • The risks and benefits of each medication you use when you are breastfeeding

What should I know about using medication to treat preeclampsia during pregnancy?

Medications for patients with preeclampsia consist of a variety of blood-pressure-lowering drugs. These include labetalol, hydralazine, nifedipine, and sodium nitroprusside, which are used for emergency control of blood pressure. Labetalol and nifedipine also are used for long-term control of blood pressure, as is a drug called methyldopa. These drugs all have risks and benefits that must be balanced, but preeclampsia is generally an emergency in which the benefits outweigh the risks, including the risks for the developing baby.

Another major category of drugs is corticosteroids, which are generally safe in pregnancy. Finally, an agent called magnesium sulfate is given to prevent seizures, the onset of which would indicate that the preeclampsia is worsening into eclampsia.

Who should NOT stop taking medication for preeclampsia during pregnancy?

Preeclampsia is a severe condition and nobody should stop taking the needed medication.

What should I know about choosing a medication for my preeclampsia during pregnancy?

You may find Pregistrys expert reports about the individual medications used to treat preeclampsia here. Additional information can also be found in the sources listed at the end of this report.

What should I know about taking a medication for preeclampsia when I am breastfeeding?

Generally, you are in an emergency situation when you have preeclampsia. Altho
ugh doctors used to think that delivery cures the condition, it can linger after delivery and in some cases can begin just after delivery. However, once the condition has resolved, which usually happens soon after delivery, the blood pressure medications often can be tapered off, as can the corticosteroids. If you are taking corticosteroids and wish to nurse, its possible to discard milk that has accumulated within the few hours since receiving a corticosteroid dose, then wait for new milk to accumulate with much lower concentrations of corticosteroid and nurse the infant from that new milk. Alternatively, you can give the infant formula until your condition has fully resolved if you do not require ongoing blood pressure medication.

Some options for what to do about that missed feeding from pumping and discarding milk include: pumping earlier in the day and saving the milk to feed in place of the discarded milk, feeding formula for that one meal a day, or simply using formula for all feedings. A lactation consultant can help you if you would like to keep breastfeeding. Ask your doctor if the medications you are prescribed in your particular situation are safe for your baby.

What alternative therapies besides medications can I use to treat preeclampsia during pregnancy?

Early delivery is the main treatment strategy for preeclampsia. If your blood pressure is in the severe range (systolic above 160 mmHg or diastolic above 110 mmHg), the baby should be delivered at 34 weeks gestation. Otherwise, the baby should be delivered at 37 weeks gestation. 

What can I do for myself and my baby when I have preeclampsia during pregnancy?

Cooperate with your physicians. Preeclampsia is a serious complication of pregnancy, but if recognized early and managed efficiently it is easily survivable both for mother and child.

Resources for preeclampsia in pregnancy:

For more information about preeclampsia, contact (800-994-9662 [TDD: 888-220-5446]) or check the following links:


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General information

It is very common for women to worry about having a miscarriage or giving birth to a child with a birth defect while they are pregnant. Many decisions that women make about their health during pregnancy are made with these concerns in mind.

For many women these concerns are very real. As many as 1 in 5 pregnancies end in a miscarriage, and 1 in 33 babies are born with a birth defect. These rates are considered the background population risk, which means they do not take into consideration anything about the health of the mom, the medications she is taking, or the family history of the mom or the baby’s dad. A number of different things can increase these risks, including taking certain medications during pregnancy.

It is known that most medications, including over-the-counter medications, taken during pregnancy do get passed on to the baby. Fortunately, most medicines are not harmful to the baby and can be safely taken during pregnancy. But there are some that are known to be harmful to a baby’s normal development and growth, especially when they are taken during certain times of the pregnancy. Because of this, it is important to talk with your doctor or midwife about any medications you are taking, ideally before you even try to get pregnant.

If a doctor other than the one caring for your pregnancy recommends that you start a new medicine while you are pregnant, it is important that you let them know you are pregnant.

If you do need to take a new medication while pregnant, it is important to discuss the possible risks the medicine may pose on your pregnancy with your doctor or midwife. They can help you understand the benefits and the risks of taking the medicine.

Ultimately, the decision to start, stop, or change medications during pregnancy is up to you to make, along with input from your doctor or midwife. If you do take medications during pregnancy, be sure to keep track of all the medications you are taking.

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