Where multiple births are expected, the period of maternity leave varies as follows:
1° For the birth of two children, this period begins twelve weeks before the presumed date of delivery and ends twenty-two weeks after the date of delivery. The suspension period prior to the presumed date of childbirth may be increased by a maximum of four weeks. The period of twenty-two weeks following childbirth is then reduced by the same amount;
2° For the birth of three or more children, this period begins twenty-four weeks before the presumed date of childbirth and ends twenty-two weeks after the date of childbirth.