At some point after you arrive in Sask. you have to register for a health care card. They probably will want to see your work permit to make sure you are legally in the country, the website is http://www.health.gov.sk.ca/how-to-register or you can call 1-800-667-7551 after you arrive if you have any questions.
From their website, it looks to me like they might give you a health card right away because you are coming from overseas, otherwise you arrive in August, you would be covered by Oct 1 at the latest. After that Sask. pays all your health care bills, hospital, doctors etc.
Do not confuse the health care with the maternity benefits. Maternity benefits come from the Employment insurance, see http://www1.servicecanada.gc.ca/en/ei/types/special.shtml#Who It is money for you to live on while you take time off work after having your baby. You would need to have worked 600 hours to be covered so if you can work full time, 40 hrs. a week, you would need 15 weeks to be covered. Then you would be entitled to maternity benefits for up to 15 weeks plus parental for up to 35 weeks but the maximum payment is $435 per week or 55% of your wages whichever is less. If you end up not qualifying for these benefits, you will be without income while you take maternity leave unless your employer offers another insurance
You see, it is also possible that your employer offers some kind of supplemental insurance or benefit plan. Many employers do. You should not need more than 3 month to qualify for it and it might pay for things like medications etc. and it might also pay you for time off work if you don't get EI.