Just a quick side note... I'm not on Gems, but all medical aids maternity benefits are "per pregnancy" so you can't spread it over 2 years unfortunately.
I am on Resolution and don't have ANY cover for gynae visits, only 12 GP visits, so I pay for my gynae visits out of pocket. It's really up to you if you want to pay out of pocket or just visit your GP for your monthly check-ups. Personally I would rather pay the R600 out of pocket and see a specialist.
It's always good to have a GAP cover as medical aids mostly pay 100% medical aid rates and some specialists can charge up to 400% medical aid rates. My GAP cover pays up to 500% medical aid rates, plus emergency room consults (which Resolution doesn't cover), co-payments, etc. And I only pay R190 per month for the GAP for both myself and my husband.