As per Maternity Benefit Act 1961, the only eligibility criteria is 80 days service in the past 12 months before being eligible of the benefits, provided your organisation has 10 or more employees. The maternity benefit does not accrue from the day of conception. As per the amendment to MB Act, the pregnant working woman is entitled to 26 weeks paid maternity leave with a maximum of 8 weeks before the expected delivery date and approximately 18 weeks after the childbirth. So you can plan to avail maternity benefit accordingly.