I am taking Adoption Leave, how does that affect my pension? 

Normally during the first 26 weeks of leave your contributions are payable based on the pay you receive and you continue to build up pensionable service.  For any period of leave over 26 weeks, you can choose to have this non-pensionable in which case you pay no contribution and build up no pensionable service for this period.  Alternatively, you can elect for this period to be pensionable in which case on your return from leave the contributions due will be deducted from your salary, usually by paying double your normal contribution until the arrears are cleared.