Definition of decidua in English:


Pronunciation /dəˈsijəwə/ /dəˈsɪdʒəwə/


  • The thick layer of modified mucous membrane which lines the uterus during pregnancy and is shed with the afterbirth.

    ‘One mechanism by which microorganisms might cause preterm labor is through ascension from the cervical/vaginal area and replication in the placenta, decidua and membranes.’
    • ‘There were large amounts of polarizable foreign body material contained within the membranes and maternal decidua, without associated inflammation or tissue reaction.’
    • ‘The tissue is sent to the laboratory where the fetal villi are dissected from the maternal decidua and either processed directly or cultured for chromosomal, DNA or biochemical analysis.’
    • ‘Ectopic decidua was found in 3% of the specimens and could be seen in both subserosal and plical areas, and was found only in postpartum patients.’
    • ‘Extreme care is used in inspecting the placenta and membranes in an effort to insure complete expression of the entire decidua.’


Late 18th century from modern Latin decidua (membrana), literally ‘falling off (membrane)’.