Antibiotics and Pregnancy
When a woman is pregnant, she and her doctor almost always think twice about using any kind of medication during pregnancy. But sometimes a medical condition requires the use of antibiotics, which can be a concern, because a recent study has linked two classes of antibiotics to birth defects.
The new study has doctors like Mark Sheffield, a neonatologist at McKay-Dee Hospital, on alert. The Utah Birth Defects Network, and seven other centers in the United States, took part in the National Birth Defects study. Researchers looked at 13-thousand pregnancies and found links between birth defects and two common antibiotics - sulfanomides (sul-FAN-o-midz) or "sulfa drugs" and nitrofurantoins (nih-trow-fur-AN-toyns) - commonly used for urinary tract infections.
“Any study shows relationship from one to the other,” says Dr. Sheffield. “It can't show a cause and effect. Serious bacterial infections are a problem in pregnancy, and if left untreated, they can cause problems. So, could the infection or the combination of the drugs and the infection together cause some of these birth defects? Yes. But, we see increased risk with these two classes than we did with other common antibiotics like penicillin, amoxicillin, ampicillin or cephalosporin, which didn't see an increased risk."
The study investigated antibiotic exposures during critical time periods - the month prior to becoming pregnant and during the first trimester, when key organs are being developed in the baby. Some of the birth defects associated with sulfa drugs include anencephaly (an-en-SEF-a-lee) - a condition in which the baby's brain does not form - as well as specific heart defects. Nitrofurantoins were linked to multiple birth defects, including cleft lip, cleft palate, two eye defects and specific heart defects.
Dr. Sheffield says these results emphasize why more studies are needed on prescription medications, over-the-counter drugs and herbal treatments during pregnancy.
“Understandably, people and companies have been reluctant to study their prescriptions, their medications, with pregnant moms or newborn babies. However, when we don't study them in a precise study, an ethical study, we then leave it up to chance whether this is a safe or unsafe medication.”
The most notorious example of drug-caused birth defects took place in the late 50s and early 60's. Believing is was safe, doctors prescribed thalidomide (thah-LID-o-mide) to thousands of pregnant women around the globe as a cure for morning sickness. They realized their mistake a short time later when babies were born with abnormalities of their arms and legs.
“It is a good example of the risks and benefits,” says Sheffield. “It was given to treat morning sickness. Every mother would choose to have morning sickness than to take a medication that puts them and their babies at risk.”
Sheffield says "caution" is the most important thing to take away from this study. He says it is important that all women in their childbearing years take at least 400 micrograms of folic acid every day to help prevent birth defects - even if they are not planning to become pregnant - and to practice healthy behaviors, like avoiding alcohol and tobacco.
“Folic acid, great success story. However, many women don't start folic acid until several months into their pregnancy or their first doctor visit and it’s too late. They have to start it before.”
If you have questions about any drugs you may be taking, talk to your doctor, or call the Utah Birth Defects Network at 1-866-818-7096.
The study was published in the November Archives of Pediatric and Adolescent Medicine.
