The prevalence of unplanned pregnancy ending in birth, associated factors, and health outcomes

Hum Reprod. 2016 Dec;31(12):2821-2833. doi: 10.1093/humrep/dew266. Epub 2016 Oct 24.


Study question: What are associated factors of unplanned pregnancies ending in birth?

Summary answer: Pregnancies that were less planned were associated with women of lower socio-economic status (SES), an unhealthier lifestyle before and during the pregnancy, more stress, and less social support.

What is known already: In Europe, the prevalence of unplanned pregnancy leading to birth varies. Unplanned pregnancy is more common among socially disadvantaged women, and associated with adverse pregnancy outcomes.

Study design, size, duration: In a cross-sectional study, 517 women were recruited from May through September 2015.

Participants/materials, setting, methods: Women were recruited from six hospitals in Flanders, Belgium. Data from self-report and medical records were collected during the first 5 days postpartum. The validated London Measure of Unplanned Pregnancy was used to collect data regarding pregnancy planning. Data were analysed with Mann-Whitney U tests, Kruskal-Wallis tests, and multiple linear regression analysis.

Main results and the role of chance: The majority of the pregnancies (83%) ending in birth were planned, 15% were ambivalent, and 2% unplanned. Women who are multigravida (95% CI -0.30 to -0.02), less well educated (95% CI 0.07-0.85), single or having a non-cohabiting relationship (95% CI 0.01-2.53), having history of drug abuse (95% CI -2.07 to -0.35), and experiencing intimate partner violence (95% CI -3.82 to -1.59) tended to have a significantly higher risk of a less planned pregnancy. Less planned pregnancies were significantly associated with initially unwanted pregnancies (P < 0.001), no folic acid or vitamin use before pregnancy (P < 0.001), lower number of prenatal visits (P = 0.03), smoking during pregnancy (P < 0.001), more stress (P = 0.002), lower relationship satisfaction (P = 0.001), and less social support (P < 0.001). Less planned pregnancies were also significantly associated with hyperemesis (P < 0.001) and shorter duration of delivery (P = 0.03). No differences were found in neonatal outcomes.

Limitations, reasons for caution: The prevalence of unplanned pregnancies is probably underestimated due to overrepresentation of women with higher SES in this study. Women's emotions may have influenced the answer to certain questions. Owing to the cross-sectional design, no causal relationships could be established.

Wider implications of the findings: This study emphasizes the importance of targeting socially disadvantaged women in the prevention of unplanned pregnancies.

Study funding/competing interests: This study was funded by the Research Foundation - Flanders (FWO). The authors have no conflict of interests.

Trial registration number: Not applicable.

Keywords: Pregnancy; newborn infant; planned pregnancy; pregnancy outcome; prevalence; reproductive behaviour; reproductive health; risk factors; unplanned pregnancy; women.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Belgium
  • Cross-Sectional Studies
  • Female
  • Humans
  • Middle Aged
  • Parturition*
  • Pregnancy
  • Pregnancy Outcome*
  • Pregnancy, Unplanned*
  • Pregnancy, Unwanted*
  • Prenatal Care
  • Prevalence
  • Social Support
  • Socioeconomic Factors
  • Young Adult