If a woman doesn't have an orgasm, she won't get pregnant. It is not necessary to have orgasm at all in order to become pregnant.
Pregnancy results from the meeting of the male sperm and the female ovum in the fallopian tube.
The pre-ejaculatory penile lubrication fluid often contains sperm, which can be deposited in the vagina, resulting in conception even if the man doesn't have an orgasm. In the female, hormones, not orgasm, control ovulation. In summary, if the sperm and egg are in the right place at the right time, conception will occur even if one or both partners have not experienced orgasm.