Risk factors for retained placenta


      Retained placenta complicates 2-3% of vaginal deliveries and is a known cause of postpartum hemorrhage. Treatment includes manual or operative placental extraction, potentially increasing risks of hemorrhage, infections, and prolonged hospital stays. We sought to evaluate risk factors for retained placenta, defined as more than 30 minutes between the delivery of the fetus and placenta, in a large US obstetrical cohort.

      Study Design

      We included singleton, vaginal deliveries ≥24 weeks (n = 91,291) from the Consortium of Safe Labor from 12 US institutions (2002–2008). Multivariable logistic regression analyses estimated the adjusted odds ratios (OR) and 95% confidence intervals (CI) for potential risk factors for retained placenta stratified by parity, adjusting for relevant confounding factors. Characteristics such as stillbirth, maternal age, race, and admission body mass index were examined.


      Retained placenta complicated 1047 vaginal deliveries (1.12%). Regardless of parity, significant predictors of retained placenta included stillbirth (nulliparous adjusted OR, 5.67; 95% CI, 3.10–10.37; multiparous adjusted OR, 4.56; 95% CI, 2.08–9.94), maternal age ≥30 years, delivery at 24 0/7 to 27 6/7 compared with 34 weeks or later and delivery in a teaching hospital. In nulliparous women, additional risk factors were identified: longer first- or second-stage labor duration, whereas non-Hispanic black compared with non-Hispanic white race was found to be protective. Body mass index was not associated with an increased risk.


      Multiple risk factors for retained placenta were identified, particularly the strong association with stillbirth. It is plausible that there could be something intrinsic about stillbirth that causes a retained placenta, or perhaps there are shared pathways of certain etiologies of stillbirth and a risk of retained placenta.

      Key words

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        • World Health Organization
        WHO Recommendations for the prevention and treatment of postpartum haemorrhage.
        World Health Organization, Geneva (Switzerland)2012: 3
        • Callahan W.M.
        • Kuklina E.V.
        • Berg C.J.
        Trends in postpartum hemorrhage: United States, 1994–2006.
        Am J Obstet Gynecol. 2010; 202: 353
        • National Collaborating Centre for Women’s and Children’s Health (NCCWCH)
        Intrapartum Care. Care of healthy women and their babies during childbirth.
        RCOG Press, London (United Kingdom)2007
        • World Health Organization
        Pregnancy, childbirth, postpartum and newborn care: a guide for essential practice.
        2nd ed. World Health Organization, Geneva (Switzerland)2006: B11
        • Combs C.A.
        • Laros R.K.
        Prolonged third stage of labor: morbidity and risk factors.
        Obstet Gynecol. 1991; 77: 863-867
        • Combs C.A.
        • Murphy E.L.
        • Laros R.K.
        Factors associated with postpartum hemorrhage with vaginal birth.
        Obstet Gynecol. 1991; 77: 69-76
        • Adelusi B.
        • Soltan M.
        • Chowdury N.
        • Kangave D.
        Risk of retained placenta: a multivariate approach.
        Acta Obstet Gynecol Scand. 1997; 76: 414-418
        • Endler M.
        • Grunewalk C.
        • Saltvedt S.
        Epidemiology of retained placenta. Oxytocin as an independent risk factor.
        Obstet Gynecol. 2014; 119: 801-808
        • Endler M.
        • Saltvedt S.
        • Cnattingius S.
        • Stephansson O.
        • Wilkstrom A.-K.
        Retained placenta is associated with pre-eclampsia, stillbirth, giving birth to a small-for-gestational-age infant and spontaneous preterm birth: a national register-based study.
        BJOG. 2014; 121: 1462-1470
        • Owolabi A.T.
        • Dare F.O.
        • Oguniola I.O.
        • Kuti O.
        • Bisiriyu L.A.
        Risk Factors for retained placenta in southwestern Nigeria.
        Singapore Med J. 2008; 49: 532-537
        • Romero R.
        • Hsu Y.C.
        • Athanassiadis A.P.
        • et al.
        Preterm delivery: a risk factor for retained placenta.
        Am J Obstet Gynecol. 1990; 193: 823-825
        • Zhang J.
        • Troendle J.
        • Reddy U.M.
        • et al.
        Contemporary cesarean delivery practice in the United States.
        Am J Obstet Gynecol. 2010; 203: 323
        • Ashwal E.
        • Melamed N.
        • Hiersch L.
        • Wiznitzer A.
        • Yogev Y.
        • Peled Y.
        The incidence and risk factors for retained placenta after vaginal delivery—a single center experience.
        J Matern Fetal Neonatal Med. 2014; 27: 1897-1900
        • Reddy U.M.
        • Goldenberg R.
        • Silver R.
        • et al.
        Sillbirth classification—developing an international consensus for research: executive summary of a Eunice Kennedy Shriver National Institute of Child Health and Human Development workshop.
        Obstet Gynecol. 2009; 114: 901-914
        • Herman A.
        • Weinraub Z.
        • Bukovsky I.
        • Arieli S.
        • Zabow P.
        • Caspi E.
        Dynamic ultrasonographic imaging of the third stage of labor: new perspectives into third-stage mechanisms.
        Am J Obstet Gynecol. 1993; 168: 1496
        • Krapp M.
        • Baschat A.A.
        • Hankeln M.
        • Gembruch U.
        Gray scale and color Doppler sonography in the third state of labor for early detection of failed placental separation.
        Ultrasound Obstet Gynecol. 2000; 15: 138-142
        • Weeks A.D.
        Placental influence on the rate of labour progression: a pilot study.
        Eur J Obstet Gynecol Reprod Biol. 2003; 106: 158
        • Heazell A.E.
        • Worton S.A.
        • Higgins L.E.
        • et al.
        Recognition of placental failure is key in saving babies' lives.
        Placenta. 2015; 36: S20-S28
        • Ptacek I.
        • Sebire N.J.
        • Man J.A.
        • Brownbill P.
        • Heazell A.E.
        Systemic review of placental pathology reports in association with stillbirth.
        Placenta. 2014; 35: 552-562
        • Kidron D.
        • Bernheim J.
        • Avriam R.
        Placental findings contributing to fetal death, a study of 120 stillbirths between 23 and 40 weeks gestation.
        Placenta. 2009; 30: 700-704
        • Horn L.C.
        • Langner A.
        • Stiehl P.
        • Wittekind C.
        • Faber R.
        Identification of the causes of intrauterine death during 310 consecutive autopsies.
        Placenta. 2004; 113: 134-138
        • Pinar H.
        • Goldenberg R.L.
        • Koch M.A.
        • et al.
        Placental findings in singleton stillbirths.
        Obstet Gynecol. 2014; 123: 325-336
        • Cedergren M.I.
        Maternal morbid obesity and the risk of adverse pregnancy outcome.
        Obstet Gynecol. 2004; 103: 219-224
        • Ehrenberg H.M.
        • Dierker L.
        • Milluzzi C.
        • Mercer B.M.
        Low maternal weight, failure to thrive in pregnancy and adverse pregnancy outcomes.
        Am J Obstet Gynecol. 2003; 189: 1726-1730
        • Robinson H.E.
        • O’Connell C.M.
        • Joseph K.S.
        • McLeod N.L.
        Maternal outcomes in pregnancies complicated by obesity.
        Obstet Gynecol. 2005; 106: 1357-1364
        • Blomberg M.
        Maternal obesity and risk of postpartum hemorrhage.
        Obstet Gynecol. 2011; 118: 561-568
        • Malti N.
        • Merzouk H.
        • Merzouk Sam Loukidi B.
        • Karaouzene N.
        • Malti A.
        • Narce M.
        Oxidative stress and maternal obesity: feto-placental unit interaction.
        Placenta. 2014; 35: 411-416
        • Martin J.A.
        • Hamilton B.E.
        • Osterman M.J.
        • Curtin S.C.
        • Matthews T.J.
        Births: final data 2012.
        Natl Vital Stat Rep. 2013; 62: 8
        • Oyelese Y.
        • Smulian J.C.
        Placenta previa, placenta accreta, and vasa previa.
        Obstet Gynecol. 2006; 107: 927-941
        • Belachew J.
        • Cnattingius S.
        • Mulic-Lutvica A.
        • Eurenius K.
        • Axelsson O.
        • Wilstrom A.K.
        Risk of retained placenta in women previously delivered by caesarean section: a population-based cohort study.
        BJOG. 2014; 121: 224-229
        • Sarit A.
        • Sokolov A.
        • Many A.
        Is epidural analgesia during labor related to retained placenta?.
        J Perinat Med. 2015; : e1-e5