Dear Abishek,
I support Prathima's views. It is the right of a female employee to avail maternity benefit. Your doubt is also right but please look into the following.
1) She has to produce a medi certificate confirming preganancy and the possible date of admittance for delivery. There is no provision whether preganany is legal or not.
2) Based on this she can plan her maternity leave 6 weeks before and after delivery
3) She can extend this leave for post-maternity complication, for which certificate is required (As a result of miscarriage or complications, and if she suffers loss of pay after 3 months, ESI can cover her loss of pay, provided she is covered under ESI eligibility)
4) She has to produce medi certificate confirming her fitness to join duty
5) After she joins duty, she may continue or resign within a month for betterment.
6) It is a privilege granted by Social Security law to be monitored by Labour Dept., wherein she continues to get the usual salary with PF/ESI statutory for the period.
7) After three months, in the event of her resigning, you have no rights to take back or deduct the maternity benefits.
Some companies follow the trick by paying one month salary prior and the remaining after she joins. If she resigns, company hopes to save 2 months salary. Even if she resigns, she can fight for the remaining due and then leave.
Regards,
Chandru