General Obstetrics and Gynecology Obstetrics
Aspirin consumption during the first trimester of pregnancy and congenital anomalies: A meta-analysis,☆☆

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Abstract

Objective: The purpose of this study was to determine, on the basis of published reports, whether aspirin use during the first trimester of pregnancy is associated with an increased risk of congenital malformations. Study design: We reviewed the literature for published studies that reported exposure to aspirin during the first trimester of pregnancy and congenital malformations. Two reviewers independently determined whether a study should be included in the final analysis and extracted the data. We calculated the pooled odds ratio and 95% CI. Results: Twenty-two studies met the inclusion criteria. In the eight studies that reported an overall risk, the risk of congenital malformations in offspring of women who were exposed to aspirin was not significantly higher than that in control subjects (odds ratio, 1.33; 95% CI, 0.94-1.89). However, a significantly increased risk of gastroschisis (odds ratio, 2.37; 95% CI, 1.44-3.88) was found. Conclusion: We found no evidence of an overall increase in the risk of congenital malformations that could be associated with aspirin. Aspirin exposure during the first trimester may be associated with an increased risk of gastroschisis. (Am J Obstet Gynecol 2002;187:·1623-30.)

Section snippets

Data sources

A search of the literature was done for studies that involved the effects of aspirin on the outcome of pregnancy. The following OVID (4.3.0) databases (and relevant segment dates) were searched electronically by a professional librarian in October 2000: MEDLINE (1966-2000), EMBASE (1980-2000), TOXLINE (1994-2000), and the EBM Reviews—Cochrane Database of Systematic Reviews (1991-2000). The MEDLINE search was repeated in April 2001. Reprotox (Reproductive Toxicology Center, Bethesda, Md; 2000),

Results

On the basis of our search strategy, 1902 citations were identified; their titles and abstracts were reviewed. Of these citations, 180 studies were selected for detailed review. Twenty-two of these studies met the inclusion criteria: 15 case-control studies,4, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 29, 30, 31, 32 6 cohort studies,2, 3, 33, 34, 35, 36 and 1 randomized control trial.25 Characteristics of the included studies are presented in the Table.

Table. Characteristics of the studies

Comment

When a drug that is commonly used by pregnant women has detrimental effects (even if they are small) on pregnancy outcome, that drug may have a significant impact on public health. Although such an effect of aspirin has been suggested,17 a large cohort study3 of >50,000 women, almost 15,000 of whom were exposed to aspirin during their first trimester, found no evidence of such an effect. When all the results of the studies that were selected for this meta-analysis were combined, we could not

Acknowledgements

We thank Editorial Services, the Hospital for Sick Children, Toronto, Ontario, Canada, for assistance in the preparation of this manuscript. E. K. was a fellow of the Research Training Centre, the Hospital for Sick Children; G. K. is a senior scientist of the Canadian Institute for Health Research and holder of the Research Leadership for Better Pharmacotherapy during Pregnancy and Lactation.

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    Supported by a grant from Pfizer, Inc, Groton, Conn, and Fetox International, Inc, Toronto, Ontario.

    ☆☆

    Reprint requests: Gideon Koren, MD, Division of Clinical Pharmacology and Toxicology, Hospital for Sick Children, 555 University Ave, Toronto, ON M5G 1X8, Canada. E-mail: [email protected]

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