If you resign at this point without rejoining, you will not be eligible for gratuity because:
Eligibility for Gratuity
There is a provision of a minimum of 5 years' continuous service in the company, which is being interrupted in your case due to your leave. You have termed it maternity leave, but the whole period cannot be termed as maternity leave because this has been defined in the Act as a 12-week period (6 weeks prenatal and 6 weeks postnatal). Hence, the period of leave without pay will be deducted from the total period of service. If this period is less than 5 years within the meaning of the Act, you shall not be eligible for gratuity.
Secondly, it is most likely that you were not granted such a long leave, and you are continuing on unauthorized leave. In such a case, you have made yourself liable for disciplinary action, not a respectable sending-off. If you insist on gratuity and other claims, and the management becomes aware of your intent, they may set up an inquiry for unauthorized absence and even terminate your services.
Hence, if you want to leave, please leave with dignity.
Regards,
AK Jain