Pregnancy is considered a medical condition, and as such is subject to waiting periods when you join/change medical aid schemes.
If you have not had medical aid for more than 90 days and are pregnant, a scheme can impose a 12 month waiting period on your pregnancy when you join, meaning that it will not cover any costs related to the pregnancy for 12 months from the time of your application.
Note that it is really up to the scheme whether it imposes a waiting period or not, and for which condition. Some schemes (usually restricted schemes that you can only belong to via your employer) do not impose any waiting periods. If you are eligible for any restricted scheme, speak to them about waiting periods and pregnancy.
You should join a medical aid anyway
Even if you are unable to find a scheme that will not impose a waiting period for your pregnancy, you should still join a medical aid as soon as you find out you are pregnant. Your newborn will not have a waiting period imposed upon birth, and if he/she needs urgent medical attention the scheme will then pay for it regardless of your waiting period.
Under no circumstances should you not disclose your pregnancy when applying for a medical scheme. This will most likely be considered “material non-disclosure” and your membership may be terminated. This could obviously severely affect your and your baby’s cover.
Below is the part of the Medical Schemes Act that deals with waiting periods: