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Praziquantel is pregnancy category B. There are no adequate and well-controlled studies in pregnant women. However, the available evidence suggests no difference in adverse birth outcomes in the children of women who were accidentally treated with praziquantel during mass prevention campaigns compared with those who were not. In mass prevention campaigns for which the World Health Organization (WHO) has determined that the benefit of treatment outweighs the risk, WHO encourages the use of praziquantel in any stage of pregnancy. For individual patients in clinical settings, the risk of treatment in pregnant women who are known to have an infection needs to be balanced with the risk of disease progression in the absence of treatment.

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).

Praziquantel is excreted in low concentrations in human milk. According to WHO guidelines for mass prevention campaigns, the use of praziquantel during lactation is encouraged. For individual patients in clinical settings, praziquantel should be used in breast-feeding women only when the risk to the infant is outweighed by the risk of disease progress in the mother in the absence of treatment.

The safety of praziquantel in children aged less than 4 years has not been established. Many children younger than 4 years old have been treated without reported adverse effects in mass prevention campaigns and in studies of schistosomiasis. For individual patients in clinical settings, the risk of treatment of children younger than 4 years old who are known to have an infection needs to be balanced with the risk of disease progression in the absence of treatment.

Albendazole is pregnancy category C. Data on the use of albendazole in pregnant women are limited, though the available evidence suggests no difference in congenital abnormalities in the children of women who were accidentally treated with albendazole during mass prevention campaigns compared with those who were not. In mass prevention campaigns for which the World Health Organization (WHO) has determined that the benefit of treatment outweighs the risk, WHO allows use of albendazole in the 2nd and 3rd trimesters of pregnancy. However, the risk of treatment in pregnant women who are known to have an infection needs to be balanced with the risk of disease progression in the absence of treatment.

It is not known whether albendazole is excreted in human milk. Albendazole should be used with caution in breastfeeding women.

The safety of albendazole in children less than 6 years old is not certain. Studies of the use of albendazole in children as young as one year old suggest that its use is safe. According to WHO guidelines for mass prevention campaigns, albendazole can be used in children as young as 1 year old. Many children less than 6 years old have been treated in these campaigns with albendazole, albeit at a reduced dose.