Abstract
Systematically review risks of an infant being born with low birth weight (LBW), preterm birth (PTB) or small for gestational age (SGA) among married and unmarried women. Medline, Embase, CINAHL, and bibliographies of identified articles were searched for English language studies. Studies reporting birth outcomes of married and unmarried (single and cohabitant) were included. Two reviewers independently collected data and assessed the quality of the studies for biases in sample selection, exposure assessment, confounder, analytical, outcome assessments, and attrition. Meta-analyses were performed using random effect model for both unadjusted and adjusted data and odds ratio (OR), and 95% confidence interval (CI) were calculated. Twenty-one studies of low to moderate risk of bias were included. Compared to married mothers unadjusted odds of (a) LBW was increased among unmarried (OR 1.46, 95%CI 1.25–1.71), single (OR 1.65, 95%CI 1.44–1.88) and cohabitating (OR 1.29, 95%CI 1.25–1.32) mothers; (b) PTB was increased among unmarried (OR 1.22, 95%CI 1.14–1.31), single (OR 1.54, 95%CI 1.39–1.72) and cohabitating (OR 1.15, 95%CI 1.08–1.23) mothers and (c) SGA birth was increased among unmarried (OR 1.45, 95%CI 1.32–1.61), single (OR 1.70, 95%CI 1.47–1.97) and cohabitating (OR 1.36, 95%CI 1.30–1.42) mothers. Meta-analyses of adjusted odds estimates confirmed these findings at marginally lower odds. Maternal unmarried status is associated with an increased risk of LBW, PTB and SGA births.
Similar content being viewed by others
Abbreviations
- LBW:
-
Low birth weight
- PTB:
-
Preterm birth
- SGA:
-
Small for gestational age
- UAOR:
-
Unadjusted odds ratio
- AOR:
-
Adjusted odds ratio
References
Blondel, B., & Zuber, M. C. (1988). Marital status and cohabitation during pregnancy: Relationship with social conditions, antenatal care and pregnancy outcome in France. Paediatric and Perinatal Epidemiology, 2(2), 125–137.
Ventural, S. J. (2009). Changing patterns of nonmarital childbearing in the United States. Hyattsville, MD: National Center for Health Statistics; Report No.: NCHS Data Brief, no. 18.
Jose, A., O’Leary, D., & Moyer, A. (2010). Does premarital cohabitation predict subsequent marital stability and marital quality? The Journal of Marriage and Family, 72, 105–116.
Bird, S. T., Chandra, A., Bennett, T., & Harvey, S. M. (2000). Beyond marital status: Relationship type and duration and the risk of low birth weight. Family Planning Perspectives, 32(6), 281–287.
Doucet, H., Baumgarten, M., & Infante-Rivard, C. (1989). Low birth weight and household structure. Journal of Developmental and Behavioral Pediatrics, 10(5), 249–252.
Hanke, W., Kalinka, J., & Sobala, W. (1998). Single motherhood, urban residence and SGA babies in Central Poland. International Journal of Gynaecology and Obstetrics, 61(3), 289–291.
Kirchengast, S., Mayer, M., & Voigt, M. (2007). Pregnancy outcome is associated with maternal marital status in Austria–even at the beginning of the 21st century. Anthropologischer Anzeiger, 65(4), 415–426.
Luo, Z. C., Wilkins, R., & Kramer, M. S. (2004). Disparities in pregnancy outcomes according to marital and cohabitation status. Obstetrics and Gynecology, 103(6), 1300–1307.
MacDonald, L. D., Peacock, J. L., & Anderson, H. R. (1992). Marital status: association with social and economic circumstances, psychological state and outcomes of pregnancy. Journal of Public Health Medicine, 14(1), 26–34.
Vagero, D., Koupilova, I., Leon, D. A., & Lithell, U. B. (1999). Social determinants of birthweight, ponderal index and gestational age in Sweden in the 1920s and the 1980s. Acta Paediatrica, 88(4), 445–453.
Raatikainen, K., Heiskanen, N., & Heinonen, S. (2005). Marriage still protects pregnancy. BJOG : An International Journal of Obstetrics and Gynaecology, 112(10), 1411–1416.
Sung, J. F., McGrady, G. A., Rowley, D. L., Hogue, C. J., Alema-Mensah, E., & Lypson, M. L. (1993). Interactive effect of race and marital status in low birthweight. Ethnicity and Disease, 3(2), 129–136.
Bennett, T. (1992). Marital status and infant health outcomes. Social Science and Medicine, 35(9), 1179–1187.
Stroup, D. F., Berlin, J. A., Morton, S. C., Olkin, I., Williamson, G. D., Rennie, D., et al. (2000). Meta-analysis of observational studies in epidemiology: a proposal for reporting. Meta-analysis Of Observational Studies in Epidemiology (MOOSE) group. The Journal of the American Medical Association, 283(15), 2008–2012.
Higgins, P. T., Green, S. (2008). Cochrane handbook for systematic reviews of interventions. The Cochrane Collaboration 2008 [cited 2008 Mar 1]; (Version 5.0.0)Available from: url: www.cochrane-handbook.org.
Higgins, J. P., & Thompson, S. G. (2002). Quantifying heterogeneity in a meta-analysis. Statistics in Medicine, 21(11), 1539–1558.
Ahmed, F. (1990). Unmarried mothers as a high-risk group for adverse pregnancy outcomes. Journal of Community Health, 15(1), 35–44.
Albrecht, S. L., Miller, M. K., & Clarke, L. L. (1994). Assessing the importance of family structure in understanding birth outcomes. Journal of Marriage and the Family, 56, 987–1003.
Amini, S. B., Catalano, P. M., & Mann, L. I. (1996). Births to unmarried mothers: trends and obstetric outcomes. Womens Health Issues, 2006, 264–272.
Auger, N., Daniel, M., Platt, R. W., Luo, Z. C., Wu, Y., & Choiniere, R. (2008). The joint influence of marital status, interpregnancy interval, and neighborhood on small for gestational age birth: A retrospective cohort study. BMC Pregnancy Childbirth, 8, 7.
Gale, R., Zengen, S., Harlap, S., Fischer, A. F., & Stevenson, D. K. (1988). Birth out of wedlock and the risk of intrauterine growth retardation. American Journal of Perinatology, 5(3), 278–282.
Golding, J., Henriques, J., & Thomas, P. (1986). Unmarried at delivery. II. Perinatal morbidity and mortality. Early Human Development, 14(3–4), 217–227.
Manderbacka, K., Merilainen, J., Hemminki, E., Rahkonen, O., & Teperi, J. (1992). Marital status as a predictor of perinatal outcome in finland. Journal of Marriage and the Family, 54, 508–515.
McIntosh, L. J., Roumayah, N. E., & Bottoms, S. F. (1995). Perinatal outcome of broken marriage in the inner city. Obstetrics and Gynecology, 85(2), 233–236.
Rantakallio, P., & Oja, H. (1990). Perinatal risk for infants of unmarried mothers over a period of 20 years. Early Human Development, 22(3), 157–169.
Zeitlin, J. A., Saurel-Cubizolles, M. J., & Ancel, P. Y. (2002). Marital status, cohabitation, and risk of preterm birth in Europe: Where births outside marriage are common and uncommon. Paediatric and Perinatal Epidemiology, 16(2), 124–130.
Hein, H. A., Burmeister, L. F., & Papke, K. R. (1990). The relationship of unwed status to infant mortality. Obstetrics and Gynecology, 76(5 Pt 1), 763–768.
Kalinka, J., Laudanski, T., Hanke, W., & Wasiela, M. (2003). Do microbiological factors account for poor pregnancy outcome among unmarried pregnant women in Poland? Fetal Diagnosis and Therapy, 18(5), 345–352.
Kiernan, K. (1999). Childbearing outside marriage in western Europe. Population Trends, Autumn(98), 11–20.
Maher, J., Macfarlane, A. (2004). Trends in live births and birthweight by social class, marital status and mother’s age, 1976–2000. Health Statistics Quarterly, Winter(23), 34–42.
Wu, L. L., & Martinson, B. C. (1993). Family structure and risk of premarital birth. American Sociological Review, 58, 210–232.
Dickute, J., Padaiga, Z., Grabauskas, V., Nadisauskiene, R. J., Basys, V., & Gaizauskiene, A. (2004). Maternal socio-economic factors and the risk of low birth weight in Lithuania. Medicina (Kaunas), 40(5), 475–482.
Koupilova, I., Vagero, D., Leon, D. A., Pikhart, H., Prikazsky, V., Holcik, J., et al. (1998). Social variation in size at birth and preterm delivery in the Czech Republic and Sweden, 1989–91. Paediatric and Perinatal Epidemiology, 12(1), 7–24.
Lekea-Karanika, V., Tzoumaka-Bakoula, C., & Matsaniotis, N. S. (1999). Sociodemographic determinants of low birthweight in Greece: A population study. Paediatric and Perinatal Epidemiology, 13(1), 65–77.
Pascoe, J. M., Chessare, J., Baugh, E., Urich, L., & Ialongo, N. (1987). Help with prenatal household tasks and newborn birth weight: Is there an association? Journal of Developmental and Behavioral Pediatrics, 8(4), 207–212.
Peacock, J. L., Bland, J. M., & Anderson, H. R. (1995). Preterm delivery: Effects of socioeconomic factors, psychological stress, smoking, alcohol, and caffeine. British Medical Journal, 311(7004), 531–535.
Vatten, L. J., & Skjaerven, R. (2003). Effects on pregnancy outcome of changing partner between first two births: Prospective population study. British Medical Journal, 327(7424), 1138.
Ramsey, C. N., Jr, Abell, T. D., & Baker, L. C. (1986). The relationship between family functioning, life events, family structure, and the outcome of pregnancy. Journal of Family Practice, 22(6), 521–527.
Peters, J., & Mengersen, K. (2008). Selective reporting of adjusted estimates in observational epidemiology studies: Reasons and implications for meta-analyses. Evaluation and the health professions, 31(4), 370–389.
Acknowledgments
We would sincerely like to thank Elizabeth Uleryk, Chief Librarian at the Hospital for Sick Children, Toronto, Ontario, Canada for her contribution in developing search strategy and running searches on a periodic basis. This study was supported by funding from Canadian Institute of Health Research (CIHR) Knowledge Synthesis/Translation grant # KRS 86242. CIHR has no role in analyses, writing of the report, interpretation of data or decision to submit the manuscript.
Author information
Authors and Affiliations
Corresponding author
Additional information
The study is conducted on behalf of Knowledge Synthesis Group of Determinants of preterm/LBW births.
Members of Knowledge Synthesis Group on determinants of LBW/preterm births:
Prakesh Shah, University of Toronto, Toronto, Ontario, Canada; Arne Ohlsson, University of Toronto, Ontario, Canada; Vibhuti Shah, University of Toronto, Toronto, Ontario, Canada; Kellie E Murphy, University of Toronto, Ontario, Canada; Sarah D McDonald, McMaster University, Hamilton, Ontario, Canada; Eileen Hutton, McMaster University, Hamilton, Ontario, Canada; Christine Newburn-Cook, University of Alberta, Edmonton, Alberta, Canada; Corine Frick, University of Calgary, Calgary, Alberta, Canada; Fran Scott, University of Toronto, Toronto, Ontario, Canada; Victoria Allen, Dalhousie University, Halifax, Nova Scotia, Canada; Joseph Beyene, University of Toronto, Toronto, Ontario, Canada.
Appendix
Appendix
See Table 5.
Rights and permissions
About this article
Cite this article
Shah, P.S., Zao, J. & Ali, S. Maternal Marital Status and Birth Outcomes: A Systematic Review and Meta-Analyses. Matern Child Health J 15, 1097–1109 (2011). https://doi.org/10.1007/s10995-010-0654-z
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10995-010-0654-z