Unprotected sex in the context of "Human penis"

Fertility in colloquial terms refers the ability to have offspring. In demographic contexts, fertility refers to the actual production of offspring, rather than the physical capability to reproduce, which is termed fecundity. The fertility rate is the average number of children born during an individual's lifetime. In medicine, fertility refers to the ability to have children, and infertility refers to difficulty in reproducing naturally. In general, infertility or subfertility in humans is defined as not being able to conceive a child after one year (or longer) of unprotected sex. The antithesis of fertility is infertility, while the antithesis of fecundity is sterility.

A copper intrauterine device (IUD), also known as an intrauterine coil, copper coil, or non-hormonal IUD, is a form of long-acting reversible contraception and one of the most effective forms of birth control available. It can also be used for emergency contraception within five days of unprotected sex. The device is placed in the uterus and lasts up to twelve years, depending on the amount of copper present in the device. It may be used for contraception regardless of age or previous pregnancy, and may be placed immediately after a vaginal delivery, cesarean delivery, or surgical abortion. Following its removal, fertility quickly returns.

Common side effects include heavy menstrual periods and increased menstrual cramps (dysmenorrhea). Rarely, the device may come out or perforate the uterine wall.