ohhh, now, our maldives transfer was lovely - think they technically called it a speed boat, but twasn't very speedy . As I remember few 'bumpy' bits, but nothing much.
Prob depends where your idland is (ie will you mostly be in the protected sea between islands or out somewhere more open) plus how big the boat is (ours was the biggest of the maldives islands, so transfer boat was actually quite big)
How pg will you be - unless I'm very wrong, can't imagine that a few bumps would dislodge a baby (feel free to tell me I'm wrong)
Many of the islands will do tranfer by seaplane for a fee...