Sickle cell disease is a blood disorder passed down from parent to child. People with sickle cell disease have abnormal hemoglobin. Hemoglobin is a protein in red blood cells that carries oxygen to the body.

Normal red blood cells are smooth, round, and flexible. They look like the letter "O." This helps them carry oxygen and move through the vessels easily. The abnormal hemoglobin in sickle cell disease makes the red blood cells stiff and sticky. They form into the shape of a sickle, or the letter "C." These sickle cells tend to clump together and can't easily move through the blood vessels. The clumps block the flow of healthy, oxygen-carrying blood. This causes pain and damages tissues.

How sickle cell disease affects pregnancy depends on whether you have sickle cell disease or sickle cell trait. Some women with sickle cell disease have no change in their disease during pregnancy. In others, the disease may get worse. Painful events called sickle cell crises may still occur in pregnancy. These events may be treated with medicines that are safe to use during pregnancy. If you have kidney disease or heart failure before you get pregnant, it may get worse during pregnancy.

In pregnancy, it's important for blood cells to be able to carry oxygen. With sickle cell anemia, the abnormal red blood cells and anemia may result in lower amounts of oxygen going to your developing baby. This can slow down the baby's growth.

Pregnant women with sickle cell trait may not have any complications. But the baby may be affected if the other parent also carries the trait. If you have sickle cell trait, experts advise that your partner should be tested before you become pregnant. Or they should be tested at the first prenatal visit. If the baby's other parent has sickle cell trait, you may need amniocentesis or other tests to see if your developing baby has the trait or the disease.

Early and regular prenatal care is important if you are pregnant and have sickle cell disease. Having prenatal visits more often allows your doctor to keep a close watch on the disease and on the health of your developing baby.

Some women may need blood transfusions to replace the sickle cells with fresh blood. These may be done several times during the pregnancy. Blood transfusions can help the blood carry oxygen and lower the number of sickle cells. If you get blood transfusions, you'll be screened for antibodies that may have been transferred in the blood and that may affect your baby. The most common antibodies are to the blood factor Rh.

Doctors don't advise using the medicine hydroxyurea during pregnancy. This medicine is often used in sickle cell disease. You may be able to take lower doses of this medicine.

Sickle cell disease may affect your developing baby. So your doctor may start testing in the second trimester to check on the health and well-being of your baby.

During labor, your doctor will give you I.V. (intravenous) fluids to help prevent fluid loss (dehydration). You may also get extra oxygen through a mask during labor. A fetal heart rate monitor is often used to watch for changes in your baby's heart rate. It also watches for signs of fetal distress. Most women can deliver vaginally, unless there are other complications.

Because sickling affects so many organs and body systems, you are more likely to have complications in pregnancy if you have sickle cell disease. Complications and increased risks may include:

• Infections, including infection in the urinary tract, kidneys, and lungs
• Gallbladder problems, including gallstones
• Heart enlargement and heart failure from anemia
• Miscarriage
• Death

Complications and increased risks for your developing baby may include:

• Severe anemia
• Poor fetal growth
• Preterm birth (before 37 weeks of pregnancy)
• Low birth weight (less than 5.5 pounds)
• Stillbirth and newborn death