placenta

noun

pla·cen·ta | \ plə-ˈsen-tə

plural placentas or placentae\ plə-ˈsen-(ˌ)tē

Definition of placenta

1 : the vascular organ in mammals except monotremes and marsupials that unites the fetus to the maternal uterus and mediates its metabolic exchanges through a more or less intimate association of uterine mucosal with chorionic and usually allantoic tissues also : an analogous organ in another animal

2 : a sporangium-bearing surface especially : the part of the carpel bearing ovules

Examples of placenta in a Sentence

Recent Examples on the Web

Early in pregnancy, new blood vessels develop and evolve to send blood to the placenta, the Mayo Clinic explains. — Korin Miller, SELF, "What You Need to Know About Toxemia, the Scary Complication Beyoncé Had While Pregnant With Twins," 6 Aug. 2018 The hazy evidence on smoking weed in pregnancy Since the late 1980s, researchers have known that THC — the active ingredient in cannabis — can cross the placenta and reach the fetus. — Julia Belluz, Vox, "More pregnant women are using marijuana. We don’t know if that’s safe.," 20 Nov. 2018 After your baby and placenta are removed, the incisions will be closed up with sutures. — Korin Miller, SELF, "Here’s What An Emergency C-Section Actually Is," 9 Aug. 2018 The appeals court wrote in its little-noticed opinion on April 24 that the placenta separated from the wall of Dellis’s womb, leading to the death. — Justin Jouvenal, Washington Post, "After disposing of the remains of her stillborn child, she was charged with a crime," 8 May 2018 At-home pregnancy tests look for the presence of human chorionic gonadotropin (hCG), which is a hormone from your placenta (the organ that helps maintain and nourish a pregnancy). — Korin Miller, SELF, "8 Facts to Know About Chemical Pregnancies," 13 Sep. 2018 Obstetricians are now testing whether there is any benefit to providing extra blood from the placenta at the time of delivery to nonbreathing infants. — Laura Landro, WSJ, "The New, Improved World of Infant Care," 16 Sep. 2018 She was diagnosed with gestational trophoblastic disease (GTD), a condition in which tumors grow in the cells that would normally develop into the placenta. — Natalie Lampert, Marie Claire, "Why Women Reeling From Miscarriage Are Turning to the Web," 1 Oct. 2018 The new blood test identifies which genes in the mother, placenta and fetus give reliable signals about gestational age and prematurity risk. — Laura Landro, WSJ, "The New, Improved World of Infant Care," 16 Sep. 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'placenta.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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12 Mar 2019

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The first known use of placenta was in 1638

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More Definitions for placenta

placenta

noun

English Language Learners Definition of placenta

medical : the organ in mammals that forms inside the mother's uterus, nourishes the unborn baby, and is pushed out of the mother after the birth of the baby

See the full definition for placenta in the English Language Learners Dictionary

placenta

noun

pla·cen·ta | \ plə-ˈsen-tə

Kids Definition of placenta

: the organ in most mammals by which the fetus is joined to the uterus of the mother and is nourished

placenta

noun

pla·cen·ta | \ plə-ˈsent-ə

plural placentas or placentae\ -ˈsent-(ˌ)ē

Medical Definition of placenta

: the vascular organ in mammals except monotremes and marsupials that unites the fetus to the maternal uterus and mediates its metabolic exchanges through a more or less intimate association of uterine mucosal with chorionic and usually allantoic tissues permitting exchange of material by diffusion between the maternal and fetal vascular systems but without direct contact between maternal and fetal blood and typically involving the interlocking of fingerlike vascular chorionic villi with corresponding modified areas of the uterine mucosa — see abruptio placentae