Maternal and Child Health Journal

, Volume 15, Issue 2, pp 205–216 | Cite as

Intention to Become Pregnant and Low Birth Weight and Preterm Birth: A Systematic Review

  • Prakesh S. Shah
  • Taiba Balkhair
  • Arne Ohlsson
  • Joseph Beyene
  • Fran Scott
  • Corine Frick


Increased stress, psychosocial problems, economic disadvantages, and lack of prenatal care are proposed to explain discrepancies in the outcome of unintended pregnancies. Studies of maternal intention and pregnancy outcomes have yielded varied results. Objective is to review studies of the risk of low birth weight (LBW)/preterm births (PTB) associated with unintended pregnancies ending in a live birth. We reviewed studies reporting on maternal intentions and outcomes from Medline, Embase, CINAHL, and bibliographies of identified articles. An unintended pregnancy was further classified as mistimed (not intended at that time) or unwanted (not desired at any time). Studies reporting an association between pregnancy intention and any of the outcomes were included. Study quality was assessed for biases in selection, exposure assessment, confounder adjustment, analyses, outcomes assessment, and attrition. Unadjusted and adjusted data from included studies were extracted by two reviewers. There were significantly increased odds of LBW among unintended pregnancies [odds ratio (OR) 1.36, 95% confidence interval (CI) 1.25, 1.48] ending in a live birth. Within the unintended category, mistimed (OR 1.31, 95% CI 1.13, 1.52) and unwanted (OR 1.51, 95% CI 1.29, 1.78) pregnancies were associated with LBW. There were statistically significantly increased odds of PTB among unintended (OR 1.31, 95% CI 1.09, 1.58), and unwanted (OR 1.50, 95% CI 1.41, 1.61) but not for mistimed (OR 1.36, 95% CI 0.96, 1.93) pregnancies. Unintended, unwanted, and mistimed pregnancies ending in a live birth are associated with a significantly increased risk of LBW and PTB.


Low birth weight Preterm birth Unintended pregnancy 



Low birth weight


Preterm birth


Small for gestational age



We would sincerely like to thank Elizabeth Uleryk, Chief Librarian at the Hospital for Sick Children, Toronto, for her contribution in developing search strategy and running searches on a periodic basis. We would also like to thank Karen Wade from Toronto Public Health Department for her critical review of this manuscript. Funding: 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.

Conflict of interest statement

None for any authors.


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Copyright information

© Springer Science+Business Media, LLC 2009

Authors and Affiliations

  • Prakesh S. Shah
    • 1
    • 2
    • 4
  • Taiba Balkhair
    • 1
    • 2
  • Arne Ohlsson
    • 1
    • 2
    • 3
    • 4
  • Joseph Beyene
    • 5
    • 6
  • Fran Scott
    • 6
    • 7
  • Corine Frick
    • 8
    • 9
  1. 1.Department of PaediatricsMount Sinai HospitalTorontoCanada
  2. 2.Department of PaediatricsUniversity of TorontoTorontoCanada
  3. 3.Department of Obstetrics and GynaecologyUniversity of TorontoTorontoCanada
  4. 4.Department of Health Policy, Management and EvaluationUniversity of TorontoTorontoCanada
  5. 5.Research Institute of the Hospital for Sick ChildrenUniversity of TorontoTorontoCanada
  6. 6.Dalla Lana School of Public HealthUniversity of TorontoTorontoCanada
  7. 7.Toronto Public HealthTorontoCanada
  8. 8.Alberta Perinatal Health ProgramUniversity of CalgaryCalgaryCanada
  9. 9.Faculty of NursingUniversity of CalgaryCalgaryCanada

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