Are orgasms safe during pregnancy? . Will they harm my baby?

Yes. An orgasm can be associated with mild uterine cramping, and unless you have a risk of preterm labor, it should be of no harm to you or the baby.
Yes, will not hurt! Absolutely. Sex can generally be had up until delivery, although recommendations say you should slack of the last month. This i, assuming you are not swinging from a "trapeze." excessive trauma can be harmful. This advice pecludes any problem such vaginal bleeding, evidence that the child might be premature. Consult your ob/gyn doc if issues arise. I feel the advice given will be similar!