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During pregnancy, some medications are safe and some are not. Some
require a higher than usual dose, and some doses change with the
advancing pregnancy.
Physicians responsible for providing care to
pregnant women are aware of these different medications and their
restrictions.
Visit the Pharmacy
 The
U.S. Food and Drug Administration has generated a grading system for
medications used during pregnancy. The categories are A, B, C, D, and X.
The significance of these categories is:
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Definitions |
Clinical Application |
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A |
"Controlled studies in women fail to demonstrate a risk
to the fetus in the first trimester (and there is no evidence of a risk in later
trimester), and the possibility of fetal harm appears remote." |
For all practical purposes, there are no Category A drugs.
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B |
"Either animal-reproduction studies have not
demonstrated a fetal risk but there are no controlled studies in pregnant women or
animal-reproduction studies have shown an adverse effect (other than a decrease in
fertility) that was not confirmed in controlled studies in women in the first trimester
(and there is no evidence of a risk in later trimesters)." |
Category B drugs include prenatal vitamins, acetaminophen
and several other medications used routinely and safely during pregnancy. If there is a
clinical need for a Category B drug, it is considered safe to use it.
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C |
"Either studies in animals have revealed adverse
effects on the fetus (teratogenic or embryocidal or other) and there are no controlled
studies in women or studies in women and animals are not available. Drugs should be given
only if the potential benefit justifies the potential risk to the fetus." |
Category C drugs have not been shown to be harmful to
fetuses (if they had been, they wouldn't be Category C drugs). However, there are some
reasons to be more concerned about these drugs than Category B drugs. If the pregnant
patient will benefit from a Category C drug, it is generally used, although most
obstetricians would prefer a Category B drug if it will give equivalently good results.
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D |
"There is positive evidence of human fetal risk, but
the benefits from use in pregnant women may be acceptable despite the risk (e.g., if the
drug is needed in a life-threatening situation or for a serious disease for which safer
drugs cannot be used or are ineffective.)" |
Category D drugs have some significant risks. They should be
used during pregnancy only when the alternatives are worse. |
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X |
"Studies in animals or human beings have demonstrated
fetal abnormalities or there is evidence of fetal risk based on human experience or both,
and the risk of the use of the drug in pregnant women clearly outweighs any possible
benefit. The drug is contraindicated in women who are or may become pregnant." |
Category X drugs should not be used during pregnancy.
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Some general rules for medication use during pregnancy are these:
- Acetaminophen is
safe
- Pseudoephedrine
is safe
- Guaifenesin is safe
- Diphenhydramine
is safe
- Local anesthetics (Xylocaine) may be used with safety, although the
addition of epinephrine to them is problematic.
Epinephrine may have
unpredictable effects on the maternal cardiovascular system (and hence
the blood flow to the baby), so
epinephrine is generally to be avoided.
- Aspirin should not be taken as it may lead to significant fetal
hemorrhage.
- Codeine,
Demerol,
Morphine and other narcotics may be used as needed
at any stage of pregnancy, but the addictive potential should be
recognized. Other than the risk of fetal drug withdrawal syndrome, these
major pain relievers are considered safe for use during pregnancy.
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Penicillins are safe
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Cephalosporins are safe
- Erythromycin is safe
- Azithromycin is safe
- Metronidazole is
safe after 14 weeks gestation. Safety prior to 14 weeks hasn't been
established.
- Tetracyclines are
unsafe at any time during pregnancy
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Aminoglycosides are basically safe during pregnancy, but renal and
ototoxicity are potential problems if the dose is high or prolonged.
- Clindamycin is safe
- Chloramphenicol
is probably safe prior to 28 weeks
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Sulfa drugs are safe prior to 34 weeks. After that, babies may
develop jaundice if exposed to sulfa.
- Quinine is only to be
used in life-threatening, chloroquine-resistant P. Falciparum
infections
- Miconazole is safe
- Clotrimazole is safe
- Quinacrine is probably safe during pregnancy
- Chloroquine may cause
congenital defects with prolonged or high doses
- Pyrimethamine is
safe after 1st trimester. Add folic acid supplement.
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Trimethoprim is safe after 1st trimester. Add folic acid
supplement.
- Primaquine may cause
hemolytic anemia in the presence of G6PD deficiency. You may use it if
needed.
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