The sun bed in pregnancy is not contraindicated but you can go for sun bed with precaution. As in pregnancy, you are at great risk of developing melasma and sunlight is a contributing factor of this problem. At the same time excessive exposure to the UV radiations can cause spinal defects in your baby. So you can have sun bed but for short time.

 The skin is far more susceptible to the effects of UV rays during pregnancy. I think your doctor would advise against using them