Sept. 18, 2007 -- Women of childbearing age may unknowingly take drugs that could cause birth defects in fetuses — that's a significant finding, considering that up to half of all pregnancies are unplanned.
A new study, published in the journal Annals of Internal Medicine, suggests that doctors should be more diligent in counseling their patients about these possible effects and prescribing birth control when necessary.
"A lot of times, women assume that their doctors will tell them everything they need to know," said lead author Dr. Eleanor Schwarz, assistant professor of obstetrics, gynecology and reproductive science at the University of Pittsburgh.
"Women need to be empowered to ask for information, because sometimes, information is being overlooked that … is relevant to their decisions about when they are going to pursue a family."
Other doctors agree that physicians must take special care when prescribing these drugs to women in their childbearing years.
"Many doctors don't know the pregnancy categories of the drugs they are prescribing," said Dr. Lisa Jones, an OB-GYN with the Greater New Bedford Community Health Center in Massachusetts.
Currently, the U.S. Food and Drug Administration categorizes drugs into five different groups.
Class A and B drugs are generally thought to be OK for women to take during pregnancy.
For drugs in class C, there is not enough evidence to determine fetal risk.
Class D drugs have been shown to cause harm to the fetus, but in some cases, the benefits of taking the drugs may outweigh the risks.
Meanwhile, Class X drugs are harmful to the fetus and should not be taken during pregnancy.
The study looked at nearly half a million women of childbearing age and discovered that one in six had obtained a class D or X drug from their pharmacist, but only half of these women were counseled on contraception at the time the prescription was given.
According to the study, 1 percent of women taking class D or X drugs became pregnant within three months of starting the medication.
And the study is not the first to identify the problem. Previous research suggests that, in as many as 6 percent of all pregnancies in the United States, women take these drugs.
A Prescription for Pregnancy Risk?
Even when women receive contraception along with a drug that poses fetal risk, they may still run the risk of a pregnancy that exposes their fetus to these drugs.
"The other big issue is whether the method of birth control the woman is employing is the most effective method available," said Schwarz. "A lot of times, the answer is no."
Using an intrauterine device, for example, may be more effective than condoms or oral contraceptives, which can be easily forgotten, she added.
However, in an age where primary-care doctors are already squeezed to do so much in short visits, addressing contraception may be difficult.
"My concern is that primary-care health-care providers are under such pressure to move patients through their offices, that contraception counseling related to this prescribing is being overlooked or not considered," said Dr. Robert Welch, chairman of the department of obstetrics and gynecology at St. John Providence Hospital in Southfield, Mich.
"This is a highly significant problem."
Women Must Ask the Right Questions
The study also found that those women taking isotretinoin — commonly known by the brand name Accutane — a Class X drug for acne had the highest rates of contraception counseling. This is likely due to an FDA program that requires women to have a negative pregnancy test and be on contraception before taking the drug.
No such requirement exists for other drugs, such as statins, which are Class X drugs, commonly used to lower cholesterol; in fact, women on this medication had the lowest rate of contraception counseling.
To combat this problem, Welch said that patients should take a stake in their own care.
"Women of childbearing age must … question their primary-care physician regarding the medications prescribed for them," he said.
"There isn't a right or a wrong answer here," Schwarz added. "What is an acceptable risk to one woman might be unacceptable to another woman. [Doctors] should get a sense of what the goals are."
Much of the concept of acceptable risk, when taking these drugs, may balance any future plans for children, Jones explained.
"This means that their [doctor] should ask them to think about how many children they plan to have, and when they plan to have them," Jones said. "Anyone who is sexually active, and not interested in seeking pregnancy, should be using some form of birth control."
Most importantly, Schwarz added, a woman should think about these risks before she actually gets pregnant. The first trimester is often when these drugs can cause the most harm.