if you have group insurance (through your employer
or your hu*****and's company), you can change insurance every year. Usually pregnancy won't be considered as pre-existing condition under group coverage.
But if you buy insurance by yourself (individual plan), you better check with sale rep to see if pregnancy is pre-existing condision.
If you have short-term di*****ility insurance, buy the max for next year if you think you will be on maternity leave during 2009.