syncytial knot

(redirected from nuclear aggregation)

syn·cy·tial knot

a localized aggregation of syncytiotrophoblastic nuclei in the villi of the placenta during early pregnancy.

syncytial knot

A multinucleated aggregate of syncytial nuclei at the surface of terminal villi in the placenta, which is rarely seen under 20 weeks of gestation. In term placentas, most syncytial knots are regarded as artefacts of tangential sectioning; the minority are syncytial sprouts, bridges, or apoptotic knots. They are consistently present, increasing with gestational age, and can be used to evaluate villous maturity.

Syncytial knots are associated with uteroplacental malperfusion (maternal diabetes, hypertension, pre-eclampsia and anaemia) and are an important datum in placental examination. In placentas without a history of malperfusion or clinical conditions associated with malperfusion, at 20 to 25 weeks, syncytial knots average 7%; at 26 to 33 weeks, 13%; at 36 weeks, 22.5%; at term, 37 to 40 weeks, term placentas have an average of 28% syncytial knots.

syncytial knot

Obstetrics A multinucleated protrusion from the trophoblastic surface which is commonly found in later pregnancy, excessively so in post-term gestation. See Chorionic villi. Cf Syncytial bud, Syncytial sprout.

syn·cy·tial knot

(sin-sish'ăl not)
A localized swelling or aggregation of syncytiotrophoblastic nuclei in the villi of the placenta during early pregnancy.
Synonym(s): nuclear aggregation.
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