Syncytiotrophoblastic fragments in first-trimester decidual veins: evidence of placental perfusion by the maternal circulation early in pregnancy.
OBJECTIVE
To determine whether maternal placental perfusion occurs in the first trimester, this study compared veins in endometrium with those in decidua. We hypothesize that veins draining the placenta become dilated and contain syncytiotrophoblastic fragments.


METHODS
Normal late-secretory endometrial biopsy specimens (n = 10) were compared with elective abortion decidua at 7 to 11 weeks (n = 100). Tissue sections were processed by routine staining and immunohistochemical studies. The cross sections of veins and glands were counted in 25 decidual biopsy specimens, and the number of syncytiotrophoblastic fragments in veins or glands was determined. Statistical significance by chi(2) or linear regression analysis was P <.05.


RESULTS
All sets of decidua had dilated veins; no secretory endometrium did. Intravenous syncytiotrophoblastic fragments were seen in 91 of 100 sets of decidua. There were more syncytial elements in veins (572/6845, 8.4%) than in glands (13/23,310, 0.06%) (P <.001).


CONCLUSIONS
Decidual veins were distended and contained syncytiotrophoblastic fragments, consistent with maternal intervillous perfusion in the first trimester.
Craven
C M
CM
Department of Obstetrics and Gynecology, School of medicine, University of Utah, Salt Lake City, USA.
Ward
K
K
D003656:Decidua / Q000098:blood supply*; D004717:Endometrium / Q000098:blood supply; D005260:Female; D005865:Gestational Age; D006801:Humans; D007150:Immunohistochemistry; D016014:Linear Models; D010928:Placental Lactogen / Q000032:analysis; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D014327:Trophoblasts / Q000737:chemistry; D014664:Vasodilation; D014680:Veins / Q000033:anatomy & histology* / Q000502:physiology
D010928:Placental Lactogen