Anthrax and Pregnancy: What You Need to Know

Oct. 16, 2001 -- Anthrax is transmitted through the anthrax bacterium (Bacillus anthracis) and can be acquired in three ways:

• Inhalation;
• Through the skin;
• Through the stomach and intestines.

Most people who are exposed to anthrax become ill within one week of exposure. Anthrax infections in the U.S. are exceedingly rare with fewer than 20 cases of the more-severe inhalation anthrax reported over the last 100 years.

I could not find any reports of a pregnant woman infected with anthrax, but that doesn't necessarily mean that it won't happen.

In general, pregnant women aren't more likely to become infected just because they are pregnant, so in theory, an infection with anthrax, as serious as it may be, should be no different in a pregnant woman. But an anthrax infection is unique in a couple of the following ways:

• During pregnancy an infection can potentially affect two people instead of one, the mother and the fetus. And each may have different problems.
• Treatment options have to consider potentially negative effects on the developing fetus.

Anthrax can be prevented with a vaccine, but it's available only to military personnel. And since the anthrax vaccine has not been tested in pregnant women, we don't really know what effect it might have.

But unlike some vaccines, such as the ones for mumps and measles containing live viruses, the anthrax vaccine does not contain live organisms. So it its safer in pregnancy than a vaccine containing live organisms. There are no special risks associated with this vaccine if it is given to a pregnant woman.

The anthrax vaccine has been used safely since the FDA approved it in 1970, and it has a long history of safety and effectiveness with few side effects reported. It does not cause sterility and there is ample evidence that it does not cause any reproductive harm.

Besides vaccination, anthrax can generally be prevented and successfully treated with different kinds of antibiotics. There are essentially two situations that require consideration of antibiotic treatment for anthrax:

• Prevention: After exposure to the anthrax bacterium, antibiotics are indicated to prevent an infection.
• Treatment: When the diagnosis of an anthrax infection has already been made, antibiotic treatment should be given.

The following antibiotics are generally recommended for prevention and treatment of anthrax, although some in this list have safety considerations for use during pregnancy and need some explanation:

• Cipro;
• Penicillin;
• Streptomycin;
• Tetracycline;
• Doxycycline;
• Erythromycin;
• Chloramphenicol.
  

Many pregnant women and their doctors are often reluctant to use some of the most effective medications in pregnancy because of fears, either perceived or real, that the fetus may be harmed. And the pregnant woman is often left without adequate treatment. However, what many often fail to consider is that the fetus will not benefit if the mother gets sick or dies as a consequence of not getting treated adequately. That's why it's important to treat the mother effectively, but also to choose medications that are not known to have a potentially adverse effect on the fetus. Here are some guidelines:

Penicillin
Penicillin and its related drugs are safe in pregnancy and no recognized adverse effects on the fetus have been shown.

Cipro
Cipro is the recommended medication for prevention after anthrax exposure. Although there are no adequate studies to tell doctors whether or not Cipro is definitely safe during pregnancy, in one study of 200 pregnant women who took Cipro and drugs related to it during pregnancy, researchers found no evidence that these drugs caused harm to the fetus.

Other studies in animals have shown some potential joint problems in young dogs -- and mice --given Cipro. Several other reports did not show an adverse effect of Cipro during pregnancy.

But since doctors just aren't sure at this point, the use of Cipro in people under 18 years old and in pregnant women is not recommended. However, because no adverse effects of Cipro have been seen in humans, and to prevent serious problems from an anthrax infection, many doctors will probably consider it for prevention during pregnancy if a woman has been exposed to anthrax

Erythromycin
Erythromycin can be used during pregnancy. No association between prenatal exposure to erythromycin and an increase in fetal problems has been seen.

Tetracycline and Doxycycline
These medications are not suggested in pregnancy since they can cause staining of the teeth in a child and slow bone growth in women who took the drug during either the second or third trimesters of pregnancy. These drugs can also cause liver damage in some pregnant women.

Streptomycin
Streptomycin should not be used in pregnancy. It is possible that streptomycin use during pregnancy may be associated with damage to the ear in the fetus, though this effect appears to occur infrequently.

Chloramphenicol
Chloramphenicol is not recommended during pregnancy because there are possible toxic problems to the mother as well as a so-called 'gray baby syndrome' in the newborn. Chloramphenicol is not associated with fetal malformations.

Final Notes

• In pregnancy, there are usually two people affected instead of one, and each may have different problems from the infection.
• There are no known reported cases of anthrax in pregnancy, so we don't know the exact effects of anthrax during pregnancy.
• Theoretically, given what we know from other infections, at least no increased risks from anthrax to the pregnant mother are expected.
• The choice of antibiotic treatment needs to consider potential fetal risks.
• Tetracycline, doxycycline, streptomycin, and chloramphenicol should be avoided because of potential fetal and maternal risks.
• Treatment with penicillin and erythromycin is safe in pregnancy.
• There are no reported human cases of fetal problems with Cipro. And although Cipro is not generally recommended for pregnant women, given the danger of an inadequately treated exposure to anthrax, many doctors would choose to use Cipro.