title: Preconceptional low-dose aspirin for the prevention of hypertensive pregnancy complications and preterm delivery after IVF: a meta-analysis with individual patient data.
abstract: OBJECTIVE
  Does preconceptionally started low-dose aspirin prevent hypertensive pregnancy complications and preterm delivery in IVF patients?
  
  
  CONCLUSIONS
  The current data do not support the use of preconceptionally started low-dose aspirin treatment for the prevention of hypertensive pregnancy complications and preterm delivery in IVF women.
  
  
  BACKGROUND
  Studies starting low-dose aspirin treatment as prevention in the second trimester of pregnancy found no or only moderate reductions in the relative risk of developing pre-eclampsia. Low-dose aspirin was possibly started too late, that is after the first episode of trophoblast invasion.
  
  
  METHODS
  We performed a meta-analysis with individual patient data (IPD), in which four authors could provide IPD on a total of 268 pregnancies (n = 131 treated with aspirin, n = 137 placebo). Data on hypertensive pregnancy complications and preterm delivery were collected.
  
  
  METHODS
  All separate databases were merged into a summary database. Treatment effect of aspirin on the incidence of hypertensive pregnancy complications (n = 187) and preterm delivery (n = 180) were estimated with odds ratios (OR) and 95% confidence intervals (95% CI) using multivariable logistic regression.
  
  
  RESULTS
  There were significantly fewer twin pregnancies in the aspirin group (OR 0.55 95% CI 0.30-0.98), but no significant differences for hypertensive pregnancy complications and preterm delivery: for singletons OR 0.62 (95% CI 0.22-1.7) and OR 0.52 (95% CI 0.16-1.7), respectively, as well as for twin pregnancies OR 1.2 (95% CI 0.35-4.4) and OR 1.6 (95% CI 0.51-5.0), respectively.
  
  
  CONCLUSIONS
  We have to bear in mind that the included studies showed clinical heterogeneity; there was variation in the duration of low-dose aspirin therapy and degree of hypertension between the different studies. Although we combined IPD from four studies, we have to realize that the studies were not powered for the outcome of the current IPD meta-analysis.
  
  
  CONCLUSIONS
  Based on the current meta-analysis with IPD we found no confirmation for the hypothesis that preconceptionally started low-dose aspirin reduces the incidence of hypertensive pregnancy complications or preterm delivery in IVF women. Larger studies are warranted.
authors.affiliation: Department of Obstetrics and Gynaecology, Centre for Reproductive Medicine, VU University Medical Centre, P.O. Box 7057, Amsterdam 1007 MB, The Netherlands. e.groeneveld@vumc.nl
authors.forename: E
authors.initials: E
authors.lastname: Groeneveld
authors.forename: M J
authors.initials: MJ
authors.lastname: Lambers
authors.forename: C B
authors.initials: CB
authors.lastname: Lambalk
authors.forename: K A
authors.initials: KA
authors.lastname: Broeze
authors.forename: M
authors.initials: M
authors.lastname: Haapsamo
authors.forename: P
authors.initials: P
authors.lastname: de Sutter
authors.forename: B C
authors.initials: BC
authors.lastname: Schoot
authors.forename: R
authors.initials: R
authors.lastname: Schats
authors.forename: B W J
authors.initials: BW
authors.lastname: Mol
authors.forename: P G A
authors.initials: PG
authors.lastname: Hompes
mesh_terms: D000328:Adult; D001241:Aspirin / Q000008:administration & dosage / Q000627:therapeutic use*; D005260:Female; D005307:Fertilization in Vitro / Q000009:adverse effects; D006801:Humans; D046110:Hypertension, Pregnancy-Induced / Q000517:prevention & control*; D016015:Logistic Models; D016017:Odds Ratio; D016742:Preconception Care; D011247:Pregnancy; D059285:Pregnancy, Twin; D047928:Premature Birth / Q000517:prevention & control*; D018570:Risk Assessment
chemical_list: D001241:Aspirin
keywords: IVF; aspirin; early pregnancy; hypertensive pregnancy complications; pre-eclampsia