Of every 100 women whose men use withdrawal, 4 will become pregnant each year if they always do it correctly, 27 if done wrong.
Coitus interruptus, also known as the rejected sexual intercourse, withdrawal or pull-out method, is a method of birth-control in which a man, during intercourse withdraws his penis from a woman's vagina prior to orgasm (and ejaculation). The man then directs his ejaculate (semen) away from his partner's vagina in an effort to avoid insemination.
This method of contraception, widely used for at least two millennia, is still in use today. This method was used by an estimated 38 million couples worldwide in 1991. Coitus interruptus does not protect against sexually transmitted infections (STIs/STDs). Pregnancy
Science of drugs including their origin, composition, pharmacokinetics,
pharmacodynamics, therapeutic use, and toxicology.
Pharmacology (from Greek φάρμακον, pharmakon, "poison" in classic Greek; "drug" in modern Greek; and -λογία, -logia "study of", "knowledge of") is the branch of medicine and biology concerned with the study of drug action, where a drug can be broadly defined as any man-made, natural, or endogenous (within the body) molecule which exerts a biochemical and/or physiological effect on the cell, tissue, organ, or organism. More specifically, it is the study of the interactions that occur between a living organism and chemicals that affect normal or abnormal biochemical function. If substances have medicinal properties, they are considered pharmaceuticals.