Influence of parity on first trimester endovascular trophoblast invasion

Fertil Steril. 2006 Apr;85(4):1032-6. doi: 10.1016/j.fertnstert.2005.09.055. Epub 2006 Mar 9.


Objective: To assess the effect of parity on endovascular trophoblastic invasion in early pregnancy.

Design: Observational study.

Setting: Teaching hospital.

Patient(s): Healthy women at 10-14 weeks of gestation.

Intervention(s): Surgical termination of pregnancy for nonmedical reasons.

Main outcome measure(s): Products of conception were blindly examined histologically with regard to the extent of decidual endovascular trophoblast invasion.

Result(s): Samples were obtained from 20 nulliparous and 10 parous women. The presence of normal intradecidual endovascular trophoblast invasion was identified with a similar frequency in both groups (P=.28). However, the proportion of decidual vessels with endovascular trophoblast invasion was significantly higher in parous women (60%) compared with nulliparous women (32%, P<.001).

Conclusion(s): Endovascular trophoblast invasion in early pregnancy is more extensive in parous women who already had an uncomplicated pregnancy than in nulliparous women.

Publication types

  • Comparative Study

MeSH terms

  • Adolescent
  • Adult
  • Embryo Implantation / physiology
  • Endothelium, Vascular / physiology*
  • Female
  • Humans
  • Parity / physiology*
  • Pregnancy
  • Pregnancy Trimester, First / physiology*
  • Trophoblasts / physiology*