International Covenant on Economic, Social and Cultural Rights - article 7(b):

Article 7

The States Parties to the present Covenant recognize the right of everyone to the enjoyment of just and favourable conditions of work which ensure, in particular:

2. Safe and healthy working conditions;

Convention on the Elimination of All Forms of Discrimination against Women - article 11.1(f):

Article 11

1. States Parties shall take all appropriate measures to eliminate discrimination against women in the field of employment in order to ensure, on a basis of equality of men and women, the same rights, in particular:

   6. The right to protection of health and to safety in working conditions, including the safeguarding of the function of reproduction.