Is bio oil/ palmers coco er/olive oil safe to use to prevent stretch marks?!?

hi,...ok so i have bought all of the 3 above, but now i do not dare use them as im not sure is they are defo safe to use? as ive read on the net that the chemicals that bio oil contains are not to be used in pregnancy e.g. rosemary/chamomile? could anyone advise plz...also am i safest to just use plain colling olive oil and rub it in- im 14 weeks pregnant thanks x