yes you def need sun esp while your pregnant, this give you vit D an essential vitamin, you should get aroun 10-20 min of direst sunlight per day if you can, darker skinned people need up to 30 min per day, mainly on your arms and face, try not to go out at peak sunburning times tho so sayout of the sun 11.30-3pm, and as previous poster said make sure you stay hydrated :)
As long as you don't overheat yourself in the sun you're okay. And like parkersmommy said, stay hydrated. I'm in the sun constantly (it's kind of hard not to in Florida lol) and if I feel like I'm getting to hot I usually go inside for a while or drink a LOT of ice water
Stay hydrated and make sure to have shade don't just stay in the sun for extended periods of time