Prednisone is frequently prescribed for asthma, one of the most common pregnancy complications. In fact, about six million women under 45 have asthma and approximately 0.5 to 1.3 percent of all pregnancies are complicated by maternal asthma, according to the Illinois Teratogen Information System. Women who continue to take the medication during pregnancy for asthma and other conditions may have a slightly higher risk of complications than women who do not take prednisone.
Prednisone, a corticosteroid medication, is given by mouth or by inhalation to prevent substances causing inflammation in the body from being released. Prednisone may be used in the treatment of diseases affecting the skin, eyes, respiratory system, gastrointestinal system, endocrine system, cardiovascular system and connective system. Examples of diseases treated with prednisone include allergies, asthma, multiple sclerosis, arthritis and lupus. More of the medication enters the mother's bloodstream when given by mouth than when it is inhaled, so the risk to the fetus is higher with oral prednisone.
Animal studies have shown an increased risk of cleft lip, a birth defect, in rats, mice and rabbits when the mother received prednisone or other corticosteroids during pregnancy. However, a human study conducted in Spain found that although the risk of cleft lip was six times higher in infants whose mothers took corticosteroids during the first trimester than in the control group, the actual number of cleft lip cases was only two out of 1,184 infants compared to the expected rate of 0.2, according to Dr. Elvira Rodríguez-Pinilla in an article published in the July 1998 issue of "Teratology."
Complications of Pregnancy
Prednisone and other corticosteroids given by mouth during pregnancy slightly increase the risk of premature birth, low birth weight and pre-eclampsia, a condition that raises the mother's blood pressure and puts both child and mother at risk for severe complications, according to the American College of Allergy, Asthma & Immunology. However, given the potentially dangerous effects of severe asthma on the mother and fetus, including lack of oxygen, the use of oral or inhaled corticosteroids during pregnancy should not be withheld, says Dr. Catherine Nelson-Piercy in the April 2001 issue of "Thorax."
If you take prednisone and become pregnant, discuss the matter with your health care provider. If you stop prednisone suddenly, you may experience dizziness, low blood pressure, low blood sugar and difficulty breathing. Researchers have concluded that the fetus may be protected from adverse effects of prednisone for several reasons: because the placenta makes the drug inactive; the drug binds to a large protein, preventing prednisone from crossing the placental barrier; and the baby's liver cannot activate the drug until the second trimester of pregnancy, according to Reproductive Immunology Associates.