To better understand miscarriage, it helps to understand the anatomy of the uterus, cervix, and Fallopian tubes.
Anatomy of the female reproductive tract includes:
- The uterus, cervix, and vaginal canal
- The fallopian tubes: these paired structures connect each ovary to the uterus.
- The ovaries: one on each side of the uterus. The normal ovary is approximately the size of an unshelled almond.
The fetus grows within the amniotic sac within the uterus:
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- Christiansen OB, Nybo Andersen AM, et al. Evidence-based investigations and treatments of recurrent pregnancy loss. Fertil Steril. 2005 Apr;83(4):821-39. 
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- Rumbold A, Middleton P, Crowther CA. Vitamin supplementation for preventing miscarriage. Cochrane Database Syst Rev. 2005 Apr 18;(2):CD004073. 
- Schauberger CW, Mathiason MA, Rooney BL. Ultrasound assessment of first-trimester bleeding. Obstet Gynecol. 2005 Feb;105(2):333-8. 
- Sotiriadis A, Makrydimas G, Papatheodorou S, Ioannidis JP. Expectant, medical, or surgical management of first-trimester miscarriage: a meta-analysis. Obstet Gynecol. 2005 May;105(5 Pt 1):1104-13.