Pregnancy is the term used to describe the period in which a fetus develops inside a woman’s womb or uterus.
Pregnancy usually lasts about 40 weeks, or just over 9 months, as measured from the last menstrual period to delivery. Health care providers refer to three segments of pregnancy, called trimesters. The major events in each trimester are described below.1
Office on Women’s Health. (2010). Stages of pregnancy. Retrieved May 20, 2016, from http://womenshealth.gov/pregnancy/you-are-pregnant/stages-of-pregnancy.html [top]
American College of Obstetricians and Gynecologists (ACOG). (2015, June). Prenatal development: How your baby grows during pregnancy. Retrieved May 20, 2016, from
http://www.acog.org/~/media/For%20Patients/faq156.pdf?dmc=1&ts=20120731T1026504777 (PDF - 70 KB) [top]
Stoll, B. J., Hansen, N. I., Bell, E. F., Shankaran, S., Laptook, A. R., Walsh, M. C., et al. (2010). Neonatal outcomes of extremely preterm infants from the NICHD Neonatal Research Network. Pediatrics, 126, 443–456. PMID: 20732945 [top]
Spong, C. Y. (2013). Defining “term” pregnancy: Recommendations from the Defining “Term” Pregnancy Workgroup. JAMA, 309(13), 2445–2446. Retrieved October 28, 2013, from http://jama.jamanetwork.com/article.aspx?articleID=1685467 [top]
Centers for Disease Control and Prevention. (n.d.).
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ACOG Committee on Obstetric Practice and Society for Maternal-Fetal Medicine. (2013; Reaffirmed 2015).
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