Pregnancy



Pregnancy (latin "graviditas") is the carrying of one or more offspring, known as a fetus or embryo, inside the uterus of a female. In a pregnancy, there can be multiple gestations, as in the case of twins or triplets. Human pregnancy is the most studied of all mammalian pregnancies. Obstetrics is the surgical field that studies and cares for high risk pregnancy. Midwifery is the non-surgical field that cares for pregnancy and pregnant women.

Childbirth usually occurs about 38 weeks after conception; i.e., approximately 40 weeks from the last normal menstrual period (LNMP) in humans. The World Health Organization defines normal term for delivery as between 37 weeks and 42 weeks. The calculation of this date involves the assumption of a regular 28-day menstrual cycle.

Embryo at 4 weeks after fertilization	Fetus at 8 weeks after fertilization	Fetus at 18 weeks after fertilization	Fetus at 38 weeks after fertilization
Relative size in 1st month (simplified illustration)	Relative size in 3rd month (simplified illustration)	Relative size in 5th month (simplified illustration)	Relative size in 9th month (simplified illustration)

Birth control

Birth control is a regimen of one or more actions, devices, sexual practices, or medications followed in order to deliberately prevent or reduce the likelihood of pregnancy or childbirth[1]. There are three main routes to preventing or ending pregnancy: the prevention of fertilization of the ovum by sperm cells ("contraception"), the prevention of implantation of the blastocyst ("contragestion"), and the chemical or surgical induction of abortion of the developing embryo or, later, foetus. In common usage, term "contraception" is often used for both contraception and contragestion.

Birth control is commonly used as part of family planning.

The history of birth control began with the discovery of the connection between coitus and pregnancy. The oldest forms of birth control included coitus interruptus, pessaries, and the ingestion of herbs that were believed to be contraceptive or abortifacient. The earliest record of birth control use is an ancient Egyptian set of instructions on creating a contraceptive pessary.

Different methods of birth control have varying characteristics. Condoms, for example, are the only methods that provide significant protection from sexually transmitted diseases. Cultural and religious attitudes on birth control vary significantly.