Pregnancy is the carrying of one or more offspring, known as a fetus or embryo, inside the uterus of a female human. 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 medical field that studies and treats pregnant patients.
You may be pregnant if you:

• Have had sexual intercourse and you have not used any method of birth control.
• Have missed one or more periods.
• ave your period, but there is a lot less bleeding than usual.
• ake birth control pills, but you missed a pill. It is especially risky to miss a pill early in the cycle or pack or to start your new pack a day or two late.

Have other symptoms of early pregnancy. Symptoms include:

• atigue.
• reast tenderness or enlargement.
• ausea or vomiting.
• ncreased urination.

Childbirth usually occurs about 38 weeks from fertilization, i.e., approximately 40 weeks from the start of the last menstruation. Thus, pregnancy lasts about nine months, although the exact definition of the English word “pregnancy” is a subject of controversy.