Tetracycline is in pregnancy category D. Tetracycline should not be used in pregnant women due to positive evidence of maternal and fetal risk. Use during pregnancy should be limited to instances when there are contraindications to the use of other appropriate antibiotics and the potential benefit justifies the known risk.

Pregnancy Category 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).

Tetracycline is excreted in breast milk. The American Academy of Pediatrics and the World Health Organization (WHO) both classify tetracycline as compatible with breast-feeding, although data on the use of tetracycline during lactation is limited. Tetracycline should be used during lactation only if the potential benefit of therapy to the mother justifies the known risk to the infant.

Tetracycline is contraindicated in children age 8 and younger as it may cause permanent discoloration of the teeth. The safety of intravenous tetracycline has not been established. Use of tetracycline in children age 8 and younger should be limited to instances when there are contraindications to the use of other appropriate antibiotics and the potential benefit justifies the known risk.

Metronidazole is in pregnancy category B. Data on the use of metronidazole in pregnant women are conflicting. The available evidence suggests use during pregnancy has a low risk of congenital anomalies. Metronidazole may be used during pregnancy in those patients who will clearly benefit from the drug, although its use in the first trimester is generally not advised.

Pregnancy Category 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).

Metronidazole is excreted in breast milk. The American Academy of Pediatrics classifies metronidazole as a drug for which the effect on nursing infants is unknown but may be of concern. The World Health Organization (WHO) advises to avoid metronidazole treatment in lactating women. Metronidazole should be used during lactation only if the potential benefit of therapy to the mother justifies the potential risk to the infant.

The safety of metronidazole in children has not been established. Metronidazole is listed as an antiamebic and antigiardiasis medicine on the WHO Model List of Essential Medicines for Children, intended for the use of children up to 12 years of age.

Oral iodoquinol has not been assigned a pregnancy category by the Food and Drug Administration. Data on the use of iodoquinol in pregnant women are limited, and risk to the embryo-fetus is unknown. Iodoquinol should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.

It is not known whether iodoquinol is excreted in breast milk. Iodoquinol should be used with caution in breastfeeding women.

The safety of iodoquinol in children has not been established.