Is it okay to sun-bathe or use tanning beds while pregnant?

No: Brief sun bathing with adequate skin protection is probably ok, but make sure you do not get uncomfortably warm. Tanning is not recommeded.

No: While a limited sun exposure is good for your health due to the skin's ability to make the active form of vitamin d, in my opinion risking sunburn and deliberate exposure to tanning uv in the beds is a bad idea whether you are pregnant or not. Short of a severe burn, pregnancy is not the issue here. Your long term skin health is what is at risk.

UV and pregnancy: There have been no controlled studies of the direct effects of tanning or tanning beds on pregnant women or their unborn child. In view of the evidence of damage from ultraviolet radiation to the skin of the mother, however, it makes sense to avoid this type of activity for the duration of pregnancy. However, research on pregnant mice showed fetal damage.