How much advance leaves be given due to illness arising of pregnancy

Respected Seniors & Dear Colleagues,

Need inputs from all around regarding a peculiar case. We have an employee on retainer mode with annual contract given to them. The employee has asked for leaves submitting the prescription for rest as she is expecting. As per the maternity act she will submit the notice of proceeding on maternity later in the year but given the illness arising out of maternity she has opted for the rest. She initially asked for 10 days of leave and has constantly extended these leaves.
Our query is that can we ask her to join back as her absence has severely hampered the functioning of her department given the ambiguity of extending leaves, the way she is doing.
She can claim maternity later when she will officially proceed on maternity but given this what is the most early period of proceeding on maternity even with medical prescription for illness arising out of maternity. Can we ask her to discontinue her services as she has not officially called for maternity leaves.

Guidance is needed.

Out of the total maternity leave of 26 weeks a maximum of eight weeks shall shall precede the expected date of delivery. Therefore, she is not eligible for any leave prior to this period. However, considering the situation she can avail her EL or other leaves.

I would like to have a clarification regarding the employment on a 'retainer mode', what is that? If she is a retainer will she be eligible for maternity or any kind of leave, NO. But at the same time, if the retainership is only an arrangement to defeat the laws, then you should give her all benefits. Obviously, a retainer will not come to your office regularly from Monday to Friday/ Saturday and remain in the office from 9 am till 5 pm and will not follow the leave rules of the organisation.