title: Subchorionic hematoma occurs more frequently in in vitro fertilization pregnancy.
abstract: OBJECTIVE
  Obstetric complications occur more frequently in pregnancies after in vitro fertilization (IVF). We attempted to determine the correlation between subchorionic hematoma and IVF pregnancies.
  
  
  METHODS
  We analyzed 194 pregnancies achieved by infertility treatment between January 2008 and February 2012 at our hospital. Among these, 67 were achieved by IVF and 127 by non-IVF approaches. We compared the frequency of subchorionic hematoma between the groups and examined the risk factors for subchorionic hematoma in the IVF group.
  
  
  RESULTS
  No significant differences regarding age and the number of uterine surgery were observed between the groups. The duration of infertility was longer, parity and the rate of luteal support were higher in the IVF group compared with that in the non-IVF group. The frequency of subchorionic hematoma was significantly higher in the IVF group (22.4%) than that in the non-IVF group (11%) (P=0.035). Univariate analysis in the IVF group demonstrated that frozen-thawed embryo transfer (OR, 6.18; 95% CI, 1.7-22.4), parity≥1 (OR, 3.67; 95% CI, 1.0-13.2) and blastocyst transfer (OR, 3.75; 95% CI, 1.1-13.3) were risk factors for the subchorionic hematoma.
  
  
  CONCLUSIONS
  The frequency of subchorionic hematoma is high in IVF pregnancies, and frozen-thawed embryo transfer, parity≥1, and blastocyst transfer may contribute to subchorionic hematoma onset.
authors.affiliation: Department of Obstetrics and Gynecology, Graduate School of Medical Science, University of the Ryukyus, Nishihara, Okinawa, Japan. Electronic address: h088421@med.u-ryukyu.ac.jp.
authors.forename: Kozue
authors.initials: K
authors.lastname: Asato
authors.affiliation: Department of Obstetrics and Gynecology, Graduate School of Medical Science, University of the Ryukyus, Nishihara, Okinawa, Japan.
authors.forename: Keiko
authors.initials: K
authors.lastname: Mekaru
authors.affiliation: Department of Obstetrics and Gynecology, Graduate School of Medical Science, University of the Ryukyus, Nishihara, Okinawa, Japan.
authors.forename: Chiaki
authors.initials: C
authors.lastname: Heshiki
authors.affiliation: Science and Technology Group, Okinawa Institute of Science and Technology Graduate University, Onna, Okinawa, Japan.
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Sugiyama
authors.affiliation: Department of Obstetrics and Gynecology, Graduate School of Medical Science, University of the Ryukyus, Nishihara, Okinawa, Japan.
authors.forename: Tadatugu
authors.initials: T
authors.lastname: Kinjyo
authors.affiliation: Department of Obstetrics and Gynecology, Graduate School of Medical Science, University of the Ryukyus, Nishihara, Okinawa, Japan.
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Masamoto
authors.affiliation: Department of Obstetrics and Gynecology, Graduate School of Medical Science, University of the Ryukyus, Nishihara, Okinawa, Japan.
authors.forename: Yoichi
authors.initials: Y
authors.lastname: Aoki
mesh_terms: D000328:Adult; D002823:Chorion; D004624:Embryo Transfer / Q000009:adverse effects* / Q000379:methods; D005260:Female; D005307:Fertilization in Vitro / Q000009:adverse effects*; D006406:Hematoma / Q000453:epidemiology*; D006801:Humans; D007246:Infertility / Q000209:etiology; D010298:Parity; D011247:Pregnancy; D011250:Pregnancy Complications, Hematologic / Q000453:epidemiology*; D012189:Retrospective Studies; D012307:Risk Factors
keywords: Blastocyst transfer; In vitro fertilization; Subchorionic hematoma; frozen–thawed embryo transfer