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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
Author(s) -
Endler M,
Saltvedt S,
Cnattingius S,
Stephansson O,
Wikström AK
Publication year - 2014
Publication title -
bjog: an international journal of obstetrics and gynaecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.157
H-Index - 164
eISSN - 1471-0528
pISSN - 1470-0328
DOI - 10.1111/1471-0528.12752
Subject(s) - obstetrics , medicine , odds ratio , small for gestational age , placenta , gestation , eclampsia , gestational age , pregnancy , population , placental abruption , gynecology , fetus , biology , environmental health , genetics
Objective To evaluate whether defective placentation disorders, i.e. pre‐eclampsia, stillbirth, small for gestational age ( SGA ), and spontaneous preterm birth, are associated with risk of retained placenta. Design Population‐based cohort study. Setting Sweden. Population Primiparous women in Sweden with singleton vaginal deliveries between 1997 and 2009 at 32–41 weeks of gestation ( n = 386 607), without placental abruption or infants with congenital malformations. Methods Risks were calculated as odds ratios ( OR s) by unconditional logistic regression with 95% confidence intervals (95% CI s) after adjustments for maternal, delivery, and infant characteristics. Main outcome measure Retained placenta, defined by the presence of both a diagnostic code (of retained placenta) and a procedure code (for the manual removal of the placenta). Results The overall rate of retained placenta was 2.17%. The risk of retained placenta was increased for women with pre‐eclampsia (adjusted OR, aOR , 1.37, 95% CI 1.21–1.54), stillbirth ( aOR 1.71, 95% CI 1.28–2.29), SGA birth ( aOR 1.47, 95% CI 1.28–1.70), and spontaneous preterm birth (32–34 weeks of gestation, aOR 2.35, 95% CI 1.97–2.81; 35–36 weeks of gestation, aOR 1.55, 95% CI 1.37–1.75). The risk was further increased for women with preterm pre‐eclampsia ( aOR 1.69, 95% CI 1.25–2.28) and preterm SGA birth ( aOR 2.19, 95% CI 1.42–3.38). There was no association between preterm stillbirth ( aOR 1.10, 95% CI 0.63–1.92) and retained placenta, but the exposed group comprised only 15 cases. Conclusions Defective placentation disorders are associated with an increased risk of retained placenta. Whether these relationships indicate a common pathophysiology remains to be investigated.