Which sexual positions are best for getting pregnant?
The man-on-top position is probably the best position for trying to get pregnant because it allows the ejaculate to flow towards the cervix. After the man ejaculates, and to optimize chances to get pregnant, the woman should remain on her back, her hips slightly elevated, for about 20-30 minutes.

Which sexual positions are not so good?
The woman-on-top position and the standing position are not the best position for getting pregnant, because the ejaculate may flow out.

Is orgasm necessary for pregnancy to occur?
Yes, at least for the man. Sperm is needed for pregnancy to occur and it is only during a man's orgasm that semen and seminal fluid moves down the man's urethra and is ejected. Does a woman have to have an orgasm to get pregnant? No as a woman does not have to have an orgasm for ovulation to occur. But it sure would be more fun!

Can I get pregnant if we have sex many days before ovulation or the day after ovulation?
The closer to ovulation sperm is deposited in the woman's genital tract, the more likely fertilization takes place. .Having intercourse more than 5 days before ovulation or over 12-24 hours after ovulation is unlikely to result in pregnancy. Pregnancy however can still occur if ovulation was miscalculated. If you do not want to get pregnant, you cannot rely on calculation alone to find your "infertile" days to prevent pregnancy.