title: Trends in twin pregnancies and mode of delivery during the last 30 years: inconsistency between guidelines and clinical practice.
abstract: OBJECTIVE
  To investigate the characteristics of twin pregnancies and their mode of delivery over a 30-year period, in order to define the current trends in clinical practice regarding twin deliveries and the factors that influence these practices.
  
  
  METHODS
  A retrospective study of twin deliveries at ≥24 weeks of gestation between January 1st, 1981 and December 31, 2010. Data concerning number of twin deliveries, mode of delivery, maternal age, use of ART techniques, parity, gestational age at delivery, birth weight and Apgar scores were collected from labor ward records.
  
  
  RESULTS
  Over the years there has been a statistically significant increase in the number of twin deliveries, twins after IVF, cesarean section rate, maternal age, nulliparity and a statistically significant reduction in term deliveries, mean birth weight and assisted vaginal deliveries. Maternal age, gestational age, parity and conception after IVF are factors related to the risk of performing a cesarean section.
  
  
  CONCLUSIONS
  Despite the lack of adequate scientific evidence concerning the optimal route of delivery in twin pregnancies it seems that over time cesarean section has become the standard of care in most of twin pregnancies. Changes in the demographic characteristics contribute among other factors to this practice.
authors.affiliation: First Department of Obstetrics and Gynecology, Alexandra Hospital, University of Athens, Athens, Greece.
authors.forename: Aris
authors.initials: A
authors.lastname: Antsaklis
authors.forename: Fotodotis M
authors.initials: FM
authors.lastname: Malamas
authors.forename: Michael
authors.initials: M
authors.lastname: Sindos
mesh_terms: D000328:Adult; D002585:Cesarean Section; D036861:Delivery, Obstetric / Q000639:trends*; D005260:Female; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D008423:Maternal Age; D010298:Parity; D017410:Practice Guidelines as Topic; D011247:Pregnancy; D059285:Pregnancy, Twin / Q000706:statistics & numerical data; D027724:Reproductive Techniques, Assisted / Q000639:trends; D012189:Retrospective Studies; D013997:Time Factors