Details

Autor(en) / Beteiligte

• Norwitz, Errol R
• Schust, Danny J
• Fisher, Susan J

Titel

Implantation and the Survival of Early Pregnancy

Ist Teil von

• The New England journal of medicine, 2001-11, Vol.345 (19), p.1400-1408

Ort / Verlag

Boston, MA: Massachusetts Medical Society

Erscheinungsjahr

2001

Quelle

MEDLINE

Beschreibungen/Notizen

• The implantation of fertilized ova and the formation of the placenta are crucial steps in reproduction. This review summarizes current information about these steps, including some of the molecular mechanisms that mediate them and how they may go awry, with consequent loss of the pregnancy. Human reproduction entails a fundamental paradox: although it is critical to the survival of the species, the process is relatively inefficient. Maximal fecundity (the probability of conception during one menstrual cycle) is approximately 30 percent. 1 Only 50 to 60 percent of all conceptions advance beyond 20 weeks of gestation. 2 Of the pregnancies that are lost, 75 percent represent a failure of implantation and are therefore not clinically recognized as pregnancies. 2 Failed implantation is also a major limiting factor in assisted reproduction. 3 A better understanding of the molecular mechanisms responsible for implantation and placentation may improve clinicians' ability to treat disorders . . .