Heres some info I got of the internet.
Tanning bed- There are no studies that provide conclusive evidence that tanning beds directly harm your baby. However it can harm you. Thirs some evidence that shows that the radiation breaks down folate and puts preconceptional and early pregnant women at higher risk for giving birth to a baby with spinal bifida or other types of neural tube defects.
On the beach- Pregnancy makes your skin more sensitive so the sun may cause hives, heat rash or worsened chloasma.
Bottle tan- This may be the best option if you are pregnant.The only concern is whether the active ingredient, dihydroxyacetone (DHA), is able to penetrate the skin.
I wasnt able to find anything stating it would harm your baby. But I also read you shouldnt stay out in the sun to long, 15 minutes is reasonable while preagnent. I got this of the internet so Im not sure how true it is. Hope this helped