Effect of high parity on occurrence of anemia in pregnancy: a cohort study

BMC Pregnancy and Childbirth

Research Article

Howard J Cabral¹  Martha M Werler¹  Daniel R Brooks¹  Mohammed A Al-Shafei²  Yahya M Al-Farsi³  Henk C Wallenburg⁴ 

[1] Department of Epidemiology, School of Public Health, Boston University, Boston, USA;Department of Family Medicine and Public Health, College of Medicine and Health Sciences, Sultan Qaboos University, Oman;Department of Family Medicine and Public Health, College of Medicine and Health Sciences, Sultan Qaboos University, Oman;Department of Epidemiology, School of Public Health, Boston University, Boston, USA;Department of Obstetrics and Gynecology, College of Medicine and Health Sciences, Sultan Qaboos University, Oman;

关键词: Risk Ratio;    Incident Case;    High Parity;    Prevalent Case;    Crude Model;   

DOI  :  10.1186/1471-2393-11-7

 received in 2010-02-15, accepted in 2011-01-20,  发布年份 2011

来源: Springer

【 摘 要 】

BackgroundStudies that explore the controversial association between parity and anaemia-in-pregnancy (AIP) were often hampered by not distinguishing incident cases caused by pregnancy from prevalent cases complicated by pregnancy. The authors' aim in conducting this study was to overcome this methodological concern.MethodsA retrospective cohort study was conducted in Oman on 1939 pregnancies among 479 parous female participants with available pregnancy records in a community trial. We collected information from participants, the community trial, and health records of each pregnancy. Throughout the follow-up period, we enumerated 684 AIP cases of which 289 (42.2%) were incident cases. High parity (HP, ≥ 5 pregnancies) accounted for 48.7% of total pregnancies. Two sets of regression analyses were conducted: the first restricted to incident cases only, and the second inclusive of all cases. The relation with parity as a dichotomy and as multiple categories was examined for each set; multi-level logistic regression (MLLR) was employed to produce adjusted models.ResultsIn the fully adjusted MLLR models that were restricted to incident cases, women with HP pregnancies had a higher risk of AIP compared to those who had had fewer pregnancies (Risk Ratio, RR = 2.92; 95% CI 2.02, 4.59); the AIP risk increased in a dose-response fashion over multiple categories of parity. In the fully adjusted MLLR models that included all cases, the association disappeared (RR = 1.11; 95% CI 0.91, 1.18) and the dose-response pattern flattened.ConclusionsThis study shows the importance of specifying which cases of AIP are incident and provides supportive evidence for a causal relation between parity and occurrence of incidental AIP.

【 授权许可】

CC BY   
© Al-Farsi et al; licensee BioMed Central Ltd. 2011