Excerpt from http://www.labourprotect.co.za/Leave.html

An employee may take at least four months’ unpaid maternity leave. This leave may start at any time from four weeks before the expected date of birth or when a doctor or midwife certifies that leave is necessary for the health of the mother or the child. An employee must notify the employer in writing, if she can write, of the date on which she wants to start maternity leave.

An employee must not work for six weeks after delivery, unless a doctor or midwife certifies that she is fit to do so. An employee who has a miscarriage during the last three months of pregnancy or who bears a stillborn child is also entitled to six weeks’ maternity leave, whether or not the employee had started maternity leave at the time.
A pregnant employee or employee nursing her child is not allowed to perform work that is hazardous to her or her child.