Don’t bother getting the maternity insurance. Since you’re already diagnosed it’s too late - the underwriter won’t cover you. Anyway if they cover you it’s only $5-15k and it’s definitely insufficient for any critical conditions you have during labor. More important is your hospital plan covered by medishield - that gives you more financial protection when you need it.
Given that these are already diagnosed… Even if you buy insurance now, those that are already diagnosed won’t be covered, but you will only be covered for other complications if I’m not wrong.