Publications by authors named "Marion E van Hoorn"

5 Publications

  • Page 1 of 1

Low-molecular-weight heparin and recurrent placenta-mediated pregnancy complications: a meta-analysis of individual patient data from randomised controlled trials.

Lancet 2016 11 6;388(10060):2629-2641. Epub 2016 Oct 6.

Centre for Practice-Changing Research, Ottawa Hospital Research Institute, University of Ottawa, Ottawa, ON, Canada.

Background: Placenta-mediated pregnancy complications include pre-eclampsia, late pregnancy loss, placental abruption, and birth of a small-for-gestational-age (SGA) neonate. These complications are leading causes of maternal, fetal, and neonatal morbidity and mortality in high-income countries. Affected women are at high risk of recurrence in subsequent pregnancies; however, effective strategies to prevent recurrence are absent. Findings from our previous study-level meta-analysis suggested that low-molecular-weight heparin reduced the risk of recurrent placenta-mediated pregnancy complications. However, we identified significant heterogeneity in the results, possibly due to trial design or inclusion criteria. To identify which patients benefit from, and which outcomes are prevented by, low-molecular-weight heparin, we did an individual patient data meta-analysis.

Methods: We did a systematic review in May, 2013, which identified eight eligible randomised trials done between 2000 and 2013 of low-molecular-weight heparin to prevent recurrent placenta-mediated pregnancy complications. We excluded studies on the basis of the wrong population, the study being ongoing, inability to confirm eligibility of participants, intervention stopped too early, and no response from the principal investigator. We requested individual patient data from the study authors for eligible women (women pregnant at the time of the study with a history of previous pregnancy that had been complicated by one or more of the following: pre-eclampsia, placental abruption, birth of an SGA neonate [<10th percentile], pregnancy loss after 16 weeks' gestation, or two losses after 12 weeks' gestation) and recoded, combined, and analysed the data for our meta-analysis. The primary outcome was a composite of early-onset (<34 weeks) or severe pre-eclampsia, birth of an SGA neonate (<5th percentile), late pregnancy loss (≥20 weeks' gestation), or placental abruption leading to delivery, assessed on an intention-to-treat basis. We assessed risk of bias with the Cochrane Risk of Bias tool. This study is registered with PROSPERO, number CRD42013006249.

Findings: We analysed data from 963 eligible women in eight trials: 480 randomly assigned to low-molecular-weight heparin and 483 randomly assigned to no low-molecular-weight heparin. Overall, the risk of bias was not substantial enough to affect decisions regarding trial inclusion. Participants were mostly white (795/905; 88%) with a mean age of 30·9 years (SD 5·0) and 403/963 (42%) had thrombophilia. In the primary analysis, low-molecular-weight heparin did not significantly reduce the risk of recurrent placenta-mediated pregnancy complications (low-molecular-weight heparin 62/444 [14%] versus no low-molecular-weight heparin 95/443 (22%) absolute difference -8%, 95% CI -17·3 to 1·4, p=0·09; relative risk 0·64, 95% CI 0·36-1·11, p=0·11). We noted significant heterogeneity between single-centre and multicentre trials. In subgroup analyses, low-molecular-weight heparin in multicentre trials reduced the primary outcome in women with previous abruption (p=0·006) but not in any of the other subgroups of previous complications.

Interpretation: Low-molecular-weight heparin does not seem to reduce the risk of recurrent placenta-mediated pregnancy complications in at-risk women. However, some decreases in event rates might have been too small for the power of our study to explore.

Funding: Canadian Institutes of Health Research.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/S0140-6736(16)31139-4DOI Listing
November 2016

Two cases of RIT1 associated Noonan syndrome: Further delineation of the clinical phenotype and review of the literature.

Am J Med Genet A 2016 07 25;170(7):1874-80. Epub 2016 Apr 25.

Department of Clinical Genetics, VU University Medical Center, Amsterdam, The Netherlands.

Mutations in RIT1, involved in the RAS-MAPK pathway, have recently been identified as a cause for Noonan syndrome. We present two patients with Noonan syndrome caused by a RIT1 mutation with novel phenotypic manifestations, severe bilateral lower limb lymphedema starting during puberty, and fetal hydrops resulting in intrauterine fetal death, respectively. Including our patients, a total of 52 patients have been reported with Noonan syndrome caused by a RIT1 mutation. Our report contributes to the delineation of the phenotype associated with RIT1 mutations and underlines that lymphatic involvement is part of this spectrum. In addition, we provide an overview of the currently described Noonan syndrome patients with RIT1 mutations in literature. © 2016 Wiley Periodicals, Inc.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/ajmg.a.37657DOI Listing
July 2016

Low-molecular-weight heparin and aspirin in the prevention of recurrent early-onset pre-eclampsia in women with antiphospholipid antibodies: the FRUIT-RCT.

Eur J Obstet Gynecol Reprod Biol 2016 Feb 19;197:168-73. Epub 2015 Dec 19.

Department of Obstetrics and Gynecology, VU University Medical Center, Amsterdam, The Netherlands.

Objective: To examine whether combined treatment with low-molecular-weight heparin (LMWH) and aspirin reduces recurrent hypertensive disorders of pregnancy (HD: pre-eclampsia, eclampsia or HELLP syndrome) in women with antiphospholipid antibodies (aPLA) and a previous delivery for HD and/or small-for-gestational-age (SGA) birthweight before 34 weeks gestation.

Study Design: This multicentre randomised controlled trial was performed between December 2000 and December 2009. Women were recruited from all eight university and six non-university/teaching hospitals in The Netherlands, two university hospitals in Australia and one university hospital in Sweden. Thirty two women with a previous delivery <34 weeks gestation with HD and/or SGA and aPLA were included before 12 weeks gestation. The intervention was daily LMWH with aspirin or aspirin alone.

Primary Outcomes: recurrent HD onset <34 weeks and recurrent HD irrespective of gestational age. Analysis by intention-to-treat.

Results: After an interim analysis, recruitment was ceased: accrual was low and the incidence of recurrent HD was far lower (3%) than expected (60%). The final analysis, performed on 32 women, shows no difference in the primary outcomes (LMWH and aspirin 0/16 versus aspirin only 1/16, risk difference 6.25% [CI -17 to 27%] for recurrent HD onset <34 weeks and 0/16 for LMWH and aspirin versus 2/16 for aspirin only, risk difference 12.5% [CI -15 to 35%] for HD irrespective of gestational age).

Conclusion: In this population of women with aPLA, who had previously had an early delivery for HD and/or SGA prior to 34 weeks gestation, combined LMWH and aspirin treatment started before 12 weeks gestation in a subsequent pregnancy did not show reduction of onset of recurrent HD either <34 weeks gestation or irrespective of gestational age, compared with aspirin alone.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.ejogrb.2015.12.011DOI Listing
February 2016

Low-molecular-weight heparin for prevention of placenta-mediated pregnancy complications: protocol for a systematic review and individual patient data meta-analysis (AFFIRM).

Syst Rev 2014 Jun 26;3:69. Epub 2014 Jun 26.

The Ottawa Hospital, Centre for Practice-Changing Research, 501 Smyth Road, Box 201, Ottawa, ON K1H 8 L6, Canada.

Background: Placenta-mediated pregnancy complications include pre-eclampsia, late pregnancy loss, placental abruption, and the small-for-gestational age newborn. They are leading causes of maternal, fetal, and neonatal morbidity and mortality in developed nations. Women who have experienced these complications are at an elevated risk of recurrence in subsequent pregnancies. However, despite decades of research no effective strategies to prevent recurrence have been identified, until recently. We completed a pooled summary-based meta-analysis that strongly suggests that low-molecular-weight heparin reduces the risk of recurrent placenta-mediated complications. The proposed individual patient data meta-analysis builds on this successful collaboration. The project is called AFFIRM, An individual patient data meta-analysis oF low-molecular-weight heparin For prevention of placenta-medIated pRegnancy coMplications.

Methods/design: We conducted a systematic review to identify randomized controlled trials with a low-molecular-weight heparin intervention for the prevention of recurrent placenta-mediated pregnancy complications. Investigators and statisticians representing eight trials met to discuss the outcomes and analysis plan for an individual patient data meta-analysis. An additional trial has since been added for a total of nine eligible trials. The primary analyses from the original trials will be replicated for quality assurance prior to recoding the data from each trial and combining it into a common dataset for analysis. Using the anonymized combined data we will conduct logistic regression and subgroup analyses aimed at identifying which women with previous pregnancy complications benefit most from treatment with low-molecular-weight heparin during pregnancy.

Discussion: The goal of the proposed individual patient data meta-analysis is a thorough estimation of treatment effects in patients with prior individual placenta-mediated pregnancy complications and exploration of which complications are specifically prevented by low-molecular-weight heparin.

Systematic Review Registration: PROSPERO (International Prospective Registry of Systematic Reviews) 23 December 2013, CRD42013006249.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/2046-4053-3-69DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4094595PMC
June 2014