Lactulose for Pregnant Women We do not recommend lactulose for pregnant women as there are insufficient clinical trials to prove the safety. Researches conducted reveal no harm to the fetus and mother. However, the number of researches is very limited. Lactulose is categorized as type B drug for pregnancy by FDA. Consult your doctor in any case. Lactulose for Breastfeeding Mothers No data has been documented which reflects side effects of lactulose in nursing newborns. However, manufacturers suggest being cautious. Consult your doctor in any case.