Pub. date: 2008 | Online Pub. Date: April 21, 2008 | DOI: 10.4135/9781412963855 | Print ISBN: 9781412941860 | Online ISBN: 9781412963855| Publisher:SAGE Publications, Inc.About this encyclopedia
Elizabeth R. Purdy
Pregnancy is the period of gestation before birth occurs. In human women, that period normally lasts for approximately 40 weeks (280 days). Women of childbearing age are encouraged to have pap smears, vaccinations, basic lab work, and pelvic examinations before becoming pregnant to identify potential problems or preexisting conditions. It is recommended that women who are trying to get pregnant begin taking vitamins containing folic acid to reduce risks of birth defects. The first sign of pregnancy is usually a missed menstrual period, and at-home pregnancy testing kits are now available that can detect pregnancies even earlier. Early prenatal care is essential. Toward the end of the pregnancy, examinations may be weekly, or even more frequently in the case of at-risk pregnancies. During the 1920s following the food shortages of World War I, dieting became a common practice in industrialized countries. From then until the 1970s, most physicians limited weight ...