This is because your new plan may not cover that condition because of the pre-existing clauses in most expatriate health plans. You will still be able to get coverage, but with your current pregnancy as an exclusion. If you are planning to have children in the near future, make sure your current health plan covers maternity. Many plans don't cover childbirth or only cover it after a 10 to 12 month moratorium. Other health plans will cover maternity as a pre-existing condition so that it either won't be covered at all or only to a certain maximum.
Childbirth expenses can be extremely high if there are complications.
Check any health policies you already have very, very carefully. Find out if your coverage extends to emergency medical services outside the country, what that coverage entails and whether that coverage is adequate if something goes terribly wrong on your holiday. Then begin shopping for any extra protection you might need Don't take chances. Understand, that whether you are out of the country for two hours or two months, accidents are never planned and ill health can come on very suddenly . You could find yourself too sick to travel home for medical treatment and we all know how expensive even a short hospital stay can be.