A plenary session of the Brazilian Federal Supreme Court (STF) recently decided, in a 10-to-1 vote, that it is unconstitutional for pregnant women and breastfeeding mothers to be required to work in unhealthy conditions, whatever the degree of unhealthiness of the activity and irrespective of whether a medical certificate has been presented recommending the cessation of the activity. The STF’s decision was released by the court on May 29, 2019.

In April 2018, the National Confederation of Metalworkers filed a Direct Action of Unconstitutionality (ADI 5938) against the labor reform section (Law No. 13,467/2017) that provided that pregnant and breastfeeding workers can be asked to do unhealthy work to a medium or minimum degree. According to the majority of the STF's Justices, the provision in items II and III of Section 394-A of the Consolidated Brazilian Labor Code violates the constitutional protection of motherhood and children as well as health, hygiene and safety standards.

The rapporteur, Justice Alexandre de Moraes, said that protection against unhealthy work involves a "protective instrumental right" for women and children, stating that "it not only safeguards women, but also offers protection to newborn babies, while fostering a harmonious mother-child relationship free from the dangers of an unhealthy environment."

To follow this decision of the STF, employers must ensure that their pregnant and breastfeeding employees not perform unhealthy work activities and not work in unhealthy environments. If these workers cannot be reassigned or relocated, they must be given paid maternity leave under the terms of Law No. 8,213/1991.