pregnancy

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In humans, the process during which a developing embryo grows within the woman's womb. It begins at conception and ends at birth, and the normal length is 40 weeks, or around nine months.

Menstruation usually stops on conception. About one in five pregnancies fails, but most of these failures occur very early on, so the woman may notice only that her period is late. After the second month, the breasts become tender, and the areas round the nipples become darker. Enlargement of the uterus can be felt at about the end of the third month, and after this the abdomen enlarges progressively. Fetal movement can be felt at about 18 weeks; a heartbeat may be heard during the sixth month. Pregnancy in animals is called gestation.

The number of stripes changed frequently until around 1800. Red, white, and blue became the colours of liberty and an inspiration for other revolutionary flags around the world. Effective date: 19 February 1937. >>