A clinical trial of HIV-infected pregnant women in several African countries and Thailand used a placebo-control group to determine whether a lower, cheaper dose of AZT could substantially reduce the transmission of HIV from pregnant women to their fetuses. The results showed the less expensive AZT treatment (that could be more widely used in poorer countries) could indeed significantly reduce vertical transmission.
However, many questioned the morality of using a placebo (no-treatment) group, which deprived control subjects of an effective treatment that could have prevented many babies from being infected with HIV. How might an act-utilitarian assess his clinical trial.