as far as i know its ok as long as you have no history of M/C. and your not too rough.

we did it with both PG's and all is fine. as the others said there are other methods.

most people leave it for the first 12 weeks (though most people i know are not interested during that time anyway) and do whatever you feel like after that.

good luck and if in doubt ask you OB or midwife.