title: Histological characteristics of the myometrium in the postpartum hemorrhage of unknown etiology: a possible involvement of local immune reactions.
abstract: The aim of this study was to evaluate the histological characteristics of the myometrium obtained in postpartum hemorrhage (PPH) of unknown etiology secondary to uterine atony. These characteristics were selected from among registered cases of clinically suspected amniotic fluid embolism (AFE) and classified as PPH of unknown etiology because of no obvious cause of PPH at Hamamatsu University School of Medicine, a registration center for clinical AFE in Japan. Immunohistochemical studies were performed on myometrium using anti-mast cell tryptase, anti-neutrophil elastase, anti-CD68, anti-CD88, anti-CD3, and anti-ZnCP-1 antibodies. Massive infiltrations of inflammatory cells with mast cell degranulation within the myometrium secondary to complement activation were observed in PPH of unknown etiology (n=34), but not in control pregnant women (n=15) or after delivery in women without PPH (n=18). The concomitant immunohistochemical detection of meconium in myometrium suggests that amniotic fluids or fetal materials are one of the candidates for inducing maternal local immune activation in the PPH of unknown etiology. Postpartum acute myometritis in the absence of an infective etiology may be a histological characteristic of PPH of unknown etiology.
authors.affiliation: Department of Obstetrics and Gynecology, Hamamatsu University School of Medicine, 1-20-1, Handayama Higashi-Ku, Hamamatsu 4313192, Shizuoka, Japan.
authors.forename: Mustari
authors.initials: M
authors.lastname: Farhana
authors.affiliation: Department of Obstetrics and Gynecology, Hamamatsu University School of Medicine, 1-20-1, Handayama Higashi-Ku, Hamamatsu 4313192, Shizuoka, Japan. Electronic address: ntamura@hama-med.ac.jp.
authors.forename: Naoaki
authors.initials: N
authors.lastname: Tamura
authors.affiliation: Department of Obstetrics and Gynecology, Hamamatsu University School of Medicine, 1-20-1, Handayama Higashi-Ku, Hamamatsu 4313192, Shizuoka, Japan.
authors.forename: Mari
authors.initials: M
authors.lastname: Mukai
authors.affiliation: Department of Obstetrics and Gynecology, Hamamatsu University School of Medicine, 1-20-1, Handayama Higashi-Ku, Hamamatsu 4313192, Shizuoka, Japan.
authors.forename: Kotomi
authors.initials: K
authors.lastname: Ikuma
authors.affiliation: Department of Obstetrics and Gynecology, Hamamatsu University School of Medicine, 1-20-1, Handayama Higashi-Ku, Hamamatsu 4313192, Shizuoka, Japan.
authors.forename: Yukiko
authors.initials: Y
authors.lastname: Koumura
authors.affiliation: Department of Obstetrics and Gynecology, Hamamatsu University School of Medicine, 1-20-1, Handayama Higashi-Ku, Hamamatsu 4313192, Shizuoka, Japan.
authors.forename: Naomi
authors.initials: N
authors.lastname: Furuta
authors.affiliation: Department of Obstetrics and Gynecology, Hamamatsu University School of Medicine, 1-20-1, Handayama Higashi-Ku, Hamamatsu 4313192, Shizuoka, Japan.
authors.forename: Chizuko
authors.initials: C
authors.lastname: Yaguchi
authors.affiliation: Department of Obstetrics and Gynecology, Hamamatsu University School of Medicine, 1-20-1, Handayama Higashi-Ku, Hamamatsu 4313192, Shizuoka, Japan.
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Uchida
authors.affiliation: Department of Obstetrics and Gynecology, Hamamatsu University School of Medicine, 1-20-1, Handayama Higashi-Ku, Hamamatsu 4313192, Shizuoka, Japan.
authors.forename: Kazunao
authors.initials: K
authors.lastname: Suzuki
authors.affiliation: Department of Obstetrics and Gynecology, Hamamatsu University School of Medicine, 1-20-1, Handayama Higashi-Ku, Hamamatsu 4313192, Shizuoka, Japan.
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Sugihara
authors.affiliation: Department of Obstetrics and Gynecology, Hamamatsu University School of Medicine, 1-20-1, Handayama Higashi-Ku, Hamamatsu 4313192, Shizuoka, Japan.
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Itoh
authors.affiliation: Department of Obstetrics and Gynecology, Hamamatsu University School of Medicine, 1-20-1, Handayama Higashi-Ku, Hamamatsu 4313192, Shizuoka, Japan.
authors.forename: Naohiro
authors.initials: N
authors.lastname: Kanayama
mesh_terms: D000328:Adult; D015703:Antigens, CD / Q000276:immunology*; D003167:Complement Activation; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D009215:Myometrium / Q000276:immunology / Q000473:pathology; D006473:Postpartum Hemorrhage / Q000276:immunology / Q000473:pathology; D011247:Pregnancy
chemical_list: D015703:Antigens, CD
keywords: Amniotic fluid embolism; Myometritis; Postpartum hemorrhage (PPH); Pregnancy; Uterine atony