In every pregnancy, a woman starts out with a 3-5% chance of having a baby with a birth defect. This is called her background risk. This sheet talks about whether exposure to tetracycline may increase the risk for birth defects over that background risk. This information should not take the place of medical care and advice from your health care provider.

What is tetracycline?

Tetracycline is an antibiotic used to treat conditions such as acne and infections. It belongs to a group of antibiotics that includes minocycline, oxytetracycline, doxycycline. In general, the information in this fact sheet applies to tetracycline and these related antibiotics. Tetracycline is usually taken orally (by mouth).

I take tetracycline. Can it make it harder for me to get pregnant?

Studies on women have not yet been done to see if taking tetracycline could make it harder for a woman to get pregnant.

I am taking tetracycline, but I would like to stop taking it before becoming pregnant. How long does the drug stay in my body?

Individuals break down medicines at different rates. On average, it takes less than 5 days for tetracycline to be cleared from the body. If you stop taking the medication now, your baby will not be exposed to tetracycline after one week. As with any medication, you should speak with your health care provider before you stop taking tetracycline.

Does taking tetracycline during my pregnancy increase the chance of miscarriage?

One small study, involving 111 women who filled a prescription for tetracycline at the beginning of their pregnancy, found a slightly higher chance of miscarriage. However, this study did not identify what illness the women were being treated for, or, if the women actually took their medication. It is difficult to know if the medical condition for which the tetracycline was prescribed could have also been a cause for the higher chance of miscarriage.

I took tetracycline during the first trimester of my pregnancy. Is there a risk for birth defects?

Unlikely. The studies are not extensive on tetracycline but have been reassuring. Researchers have studied the outcome of pregnancies when women took tetracycline during the first trimester (the first 14 weeks). This is the time when the organs are forming in the baby. These studies have not shown an increased chance for major birth defects in children exposed to tetracycline in the first trimester of pregnancy.

Is there a risk for other problems if I take tetracycline at any time during pregnancy?

Yes. Studies suggest that if tetracycline is taken after the fourth month of pregnancy, there is a chance for discoloration (gray or yellowish brown) of the “baby” teeth. The discoloration of the baby teeth is due to calcification (hardening) of the teeth. Although this changes the look of the teeth, it does not seem to change the development of the outer covering, the enamel, or, the chance of getting cavities. It is not clear how many babies who are exposed in pregnancy will go on to have toot staining. It is suggested that the use of tetracycline be avoided after four months of pregnancy unless there is a special reason for your healthcare provider to prescribe the medication.

I have heard that tetracycline also affects the bones of developing babies. Is this true?

Tetracycline appears to affect the calcification (hardening) of the bones and teeth, and it also appears to cause reduced growth of some bones while the baby is being exposed to the medication. Even though the tooth discoloration is permanent, the bone growth seems to return to normal after the exposure to tetracycline ends.

What if I am taking one of the other medications in this group such as minocycline, oxytetracycline, or doxycycline instead of tetracycline? Does that still put my baby at risk?

Studies have not looked at minocycline or oxytetracycline use during pregnancy. Since these antibiotics are like tetracycline, it is possible that they could also affect a baby’s teeth and bones in the same way if taken in the second and third trimesters of pregnancy. There are some reports of babies with tooth discoloration after similar exposures. For this reason, it is best to use the same caution with these medications.

Can I breastfeed my baby if I am taking tetracycline?

Yes if it is short-term. The bones and teeth in the baby continue to harden until one year of age. Theoretically, if a baby is exposed to tetracycline in breast milk, it could cause tooth discoloration and delayed bone growth. However, only very low levels of tetracycline pass into breast milk. At this time, there have been no problems reported in babies exposed to tetracycline through breast milk.

The World Health Organization (WHO) Working Group on Human Lactation states that when tetracycline is used for 7-10 days while nursing, the risk to the infant appears to be low. However, other types of antibiotics may be suggested for use while breastfeeding. Be sure to talk to your health care provider about all of your breastfeeding questions.

What if the father of the baby takes tetracycline?

There is currently no information to suggest that use of tetracycline by the father would be harmful to sperm or increase the risk for birth defects. In general, exposures that fathers have are unlikely to increase risks to a pregnancy. For more information, please see the MotherToBaby fact sheet Paternal Exposures and Pregnancy at

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