Taking antibiotics during pregnancy
It depends. Some antibiotics are safe to take throughout pregnancy, some pose known risks to a developing baby, and a host of others fall in between.
When a drug falls into this last category, it's because there's not enough safety information available or the potential risk of the drug needs to be carefully weighed against the harmful effects of the condition it's being used to treat.
In other words, if you're very sick and an antibiotic is the only thing that will help you get better, you may need to take it in spite of the potential risk to your baby. In some cases, not treating your illness could be more risky for your baby's health than exposing him to an antibiotic.
What's more, as with any medication, the safety of a particular antibiotic depends not only on the characteristics of the drug itself but on factors such as how much you take, how long you take it, and where you are in your pregnancy.
With so many antibiotics available, it isn't possible to list all of them here. But common antibiotics that are generally considered safe during pregnancy include penicillins (such as amoxicillin and ampicillin), cephalosporins (such as cephalexin), and erythromycin.
Some experts used to suspect that the drug metronidazole (used to treat some vaginal infections, such as trichomoniasis and bacterial vaginosis, as well as other kinds of infections) caused birth defects. New research hasn't supported this suspected link, and it's now considered safe in most cases.
If you get recurrent urinary tract infections or if the infection gets into your kidneys, your caregiver may recommend taking nitrofurantoin (trade name Macrodantin or Macrobid) for the rest of your pregnancy to prevent another infection. You should stop taking this drug at about 36 weeks (or immediately if you go into preterm labor) because there's a very small risk that it will destroy some of your baby's red blood cells if you take it within several days of delivery.
Trimethoprim is an ingredient often found in drugs used to treat urinary tract infections, such as Bactrim and Septra). Trimethoprim is not a good option during pregnancy because it blocks the effects of folic acid. Folic acid is crucial during pregnancy and preconception because it reduces your baby's risk of developing neural tube and other birth defects.
If you have no other choice and must take one of these drugs, be sure to take your daily prenatal vitamin as well. Research suggests that taking a daily folic acid supplement of at least 400 micrograms (prenatal vitamins generally contain twice this amount) can overcome the blocking effects of trimethoprim.
Antibiotics you should avoid altogether during pregnancy include streptomycin (used to treat tuberculosis), which can cause hearing loss in your baby, and tetracycline (including minocycline, oxytetracycline, and doxycycline), used to treat acne and respiratory infections. If you take tetracycline in the second or third trimester, it could discolor your developing baby's teeth.