title: [Birth characteristics due to in vitro fertilization (IVF) techniques].
abstract: OBJECTIVE
  To determine the number of deliveries after 31 weeks gestation (w), from in vitro fertilization (IVF), including Intracytoplasmic Sperm Injection (ICSI), and to compare characteristics with those achieved by natural fertilization (NF). We analyse twin and singleton pregnancies separately.
  
  
  METHODS
  This descriptive and prospective study monitors children from foetus, from 12 weeks after IVF, to 12 months of age, including the newborn period. There were 7008 newborns between 1st January 2004 and 31st March 2007 of which there were 113 from IVF and 6895 from NF.
  
  
  RESULTS
  Twin-pregnancies in NF is 2.4%, whereas in IVF it is 56.6%, (p<0.001). Mean mother age is 28+/-9 years (y) in NF and 36+/-4y in IVF singletons (p<0.05), and 29+/-10 y in NF and 35+/-4 y in IVF twins (p<0.05). Mean gestational age is 38+/-4 w and 39+/-2w in NF and IVF singletons and 36+/-1 w in NF and IVF twins. No statistically significant differences were found in prematurity rate (<37 w) and low birth weight (< 2500g) between singletons and twins from IVF or NF. Caesarean sections were 23.13% and 51.02% from singleton NF and IVF (p<0.001). No statistically differences were found between twins NF (71.42%) and IVF (79.69%). Malformations at birth were observed in 5.3% of IVF and in 1.1% of NF newborns (p<0.002). Relative risk of malformations (RR) IVF versus NF is 4.83 (95% CI, 2.14-10.83).
  
  
  CONCLUSIONS
  Only 1.61% of newborns comes from IVF techniques. There are significant differences in age of mother, twin- pregnancies, caesarean sections (singletons) and congenital defects between them and NF newborns. There were no differences found in prematurity and low birth weight between them and NF newborns, when compared by number of foetus.
authors.affiliation: Servicio de Pediatría, Hospital Universitario Doctor Peset, Valencia, España; Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Valencia, España. amparo@sanchiscalvo.e.telefonica.net
authors.forename: A
authors.initials: A
authors.lastname: Sanchis Calvo
authors.forename: B
authors.initials: B
authors.lastname: Marcos Puig
authors.forename: L
authors.initials: L
authors.lastname: Juan García
authors.forename: M M
authors.initials: MM
authors.lastname: Morales Suárez-Varela
authors.forename: A
authors.initials: A
authors.lastname: Abeledo Gómez
authors.forename: R
authors.initials: R
authors.lastname: Balanzá Machancosa
authors.forename: A
authors.initials: A
authors.lastname: Pineda Caplliure
authors.forename: G
authors.initials: G
authors.lastname: Tamarit Bordes
authors.forename: N
authors.initials: N
authors.lastname: Gimeno Clemente
authors.forename: L
authors.initials: L
authors.lastname: Cerveró Martí
mesh_terms: D000013:Congenital Abnormalities / Q000453:epidemiology* / Q000209:etiology*; D005307:Fertilization in Vitro / Q000009:adverse effects*; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature; D011446:Prospective Studies