title: Pregnancy outcome after fetal reduction in women with a dichorionic twin pregnancy.
abstract: OBJECTIVE
  What are the pregnancy outcomes for women with a twin pregnancy that is reduced to a singleton pregnancy?
  
  
  CONCLUSIONS
  Fetal reduction of a twin pregnancy significantly improves gestational age at birth and neonatal birthweight, however at an increased risk of pregnancy loss and preterm delivery.
  
  
  BACKGROUND
  Women with a multiple pregnancy are at increased risk for preterm delivery. Fetal reduction can be considered in these women.
  
  
  METHODS
  Retrospective cohort study of 118 women with a twin pregnancy reduced to a singleton pregnancy between 2000 and 2010.
  
  
  METHODS
  We compared the outcome of pregnancy in consecutive women with a dichorionic twin pregnancy that was reduced to a singleton pregnancy to that of women with a dichorionic twin pregnancy that was managed expectantly and women with a primary singleton pregnancy. Reductions were performed between 10-23(6/7) weeks' gestation by intracardiac or intrathoracic injection of potassium chloride, mostly for congenital anomalies. We compared median gestational age, pregnancy loss <24 weeks, preterm delivery <32 weeks, neonatal birthweight and perinatal deaths.
  
  
  RESULTS
  We studied 118 women with a twin pregnancy that was reduced to a singleton, 818 women with an ongoing dichorionic twin pregnancy and 611 women with a primary singleton pregnancy. Loss of the entire pregnancy <24 weeks and preterm delivery occurred significantly more in the reduction group compared with the ongoing twin group (11.9 versus 3.1% <24 weeks, P< 0.001 and 18.6 versus 11.5% <32 weeks, respectively, P < 0.001). In the reduction group, the percentage of women without any surviving child was significantly higher compared with the ongoing twin and primary singleton group (14.4, 3.4 and 0.7%, respectively, P < 0.001). Median gestational age was 38.9 weeks (interquartile range (IQR) 34.7-40.3) for reduced pregnancies, 37.1 weeks (IQR 35.3-38.1) for ongoing twin pregnancies and 40.1 (IQR 39.1-40.9) for primary singletons (P < 0.001 for all comparisons).
  
  
  CONCLUSIONS
  The main limitations of the study were its retrospective character, and the fact that indications for reduction were heterogeneous.
  
  
  CONCLUSIONS
  In women with a dichorionic twin pregnancy fetal reduction increases median gestational age only at considerable risk of complete early pregnancy loss.
  
  
  BACKGROUND
  The study was not funded. None of the authors has conflicts of interest.
authors.affiliation: Department of Obstetrics and Gynecology, VU University Medical Center, Amsterdam, The Netherlands lidewijvandemheen@gmail.com.
authors.forename: L
authors.initials: L
authors.lastname: van de Mheen
authors.affiliation: Department of Obstetrics and Gynecology, Academic Medical Center, Amsterdam, The Netherlands.
authors.forename: S M P
authors.initials: SM
authors.lastname: Everwijn
authors.affiliation: Department of Obstetrics and Prenatal Medicine, Erasmus Medical Center, Rotterdam, The Netherlands.
authors.forename: M F C M
authors.initials: MF
authors.lastname: Knapen
authors.affiliation: Department of Obstetrics and Gynecology, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: M C
authors.initials: MC
authors.lastname: Haak
authors.affiliation: Department of Obstetrics and Gynecology, VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: M A J
authors.initials: MA
authors.lastname: Engels
authors.affiliation: Department of Obstetrics and Gynecology, University Medical Center, Utrecht, The Netherlands.
authors.forename: G T R
authors.initials: GT
authors.lastname: Manten
authors.affiliation: Department of Obstetrics and Gynecology, Rijnstate Hospital, Arnhem, The Netherlands.
authors.forename: H A
authors.initials: HA
authors.lastname: Zondervan
authors.affiliation: Department of Obstetrics and Gynecology, Maastricht University Medical Center, Maastricht, The Netherlands.
authors.forename: S A M
authors.initials: SA
authors.lastname: Wirjosoekarto
authors.affiliation: Department of Obstetrics and Gynecology, Radboud University Medical Center, Nijmegen, The Netherlands.
authors.forename: J M G
authors.initials: JM
authors.lastname: van Vugt
authors.affiliation: Department of Obstetrics and Gynecology, University Medical Center, Groningen, The Netherlands.
authors.forename: J J H M
authors.initials: JJ
authors.lastname: Erwich
authors.affiliation: Department of Obstetrics and Gynecology, University Medical Center, Groningen, The Netherlands.
authors.forename: C M
authors.initials: CM
authors.lastname: Bilardo
authors.affiliation: Department of Obstetrics and Gynecology, Onze Lieve Vrouwe Gasthuis, Amsterdam, The Netherlands.
authors.forename: M G
authors.initials: MG
authors.lastname: van Pampus
authors.affiliation: Department of Obstetrics and Gynecology, VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: C J M
authors.initials: CJ
authors.lastname: de Groot
authors.affiliation: The Robinson Institute, School of Reproductive Health and Paediatrics, University of Adelaide, Adelaide, Australia.
authors.forename: B W J
authors.initials: BW
authors.lastname: Mol
authors.affiliation: Department of Obstetrics and Gynecology, Academic Medical Center, Amsterdam, The Netherlands.
authors.forename: E
authors.initials: E
authors.lastname: Pajkrt
mesh_terms: D000022:Abortion, Spontaneous / Q000209:etiology*; D000328:Adult; D005260:Female; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D011247:Pregnancy; D011256:Pregnancy Outcome; D018607:Pregnancy Reduction, Multifetal / Q000009:adverse effects*; D059285:Pregnancy, Twin; D012189:Retrospective Studies; D014429:Twins, Dizygotic
keywords: congenital abnormality; fetal reduction; pregnancy outcome; twin pregnancy