Risk Factors and Birth Outcomes Associated with Teenage Pregnancy: A Canadian Sample

J Pediatr Adolesc Gynecol. 2020 Apr;33(2):153-159. doi: 10.1016/j.jpag.2019.10.006. Epub 2019 Oct 18.


Study objective: To examine the extent to which socioeconomic status, mental health, and substance use are associated with teenage pregnancies in Southwestern Ontario (SWO), and whether these pregnancies are at an elevated risk for adverse birth outcomes, after controlling for medical, behavioral, and socioeconomic status factors.

Design: Retrospective cohort study using perinatal and neonatal databases.

Setting: Tertiary care hospital in SWO.

Participants: Women residing in SWO who gave birth to singleton infants without congenital anomalies between 2009 and 2014. Teenage pregnancies (19 years of age or younger) were compared with pregnancies of women 20-34 years and 35 years or older.

Interventions: None.

Main outcome measures: Low birth weight (LBW), very LBW, term LBW, preterm birth, very preterm birth, low and very low Apgar score, and fetal macrosomia.

Results: Of 25,263 pregnant women, 1080 (4.3%) were 19 years of age or younger. Approximately 18% of teenage mothers lived in socioeconomically disadvantaged neighborhoods, compared with 11% of mothers aged 20-34 and 9% of women 35 years of age or older (P < .001). Teenage mothers had higher rates of depression during pregnancy (9.8%) than mothers 20-34 years (5.8%) and those 35 years of age or older (6.8%; P < .001). Young mothers self-reported higher tobacco, marijuana, and alcohol use during pregnancy than adult mothers (P < .001). Teenage pregnancy increased the risk of a low Apgar score (adjusted odds ratio, 1.56; 95% confidence interval, 1.21-2.02), but was not associated with other birth outcomes after adjusting for covariates.

Conclusion: Teenage pregnancy is associated with a higher risk of socioeconomic disadvantage, mental health problems, and substance use during pregnancy, but is largely unrelated to adverse birth outcomes in SWO.

Keywords: Alcohol drinking; Apgar score; Cannabis; Fetal macrosomia; Infant; Low birth weight; Mental health; Pregnancy in adolescence; Premature birth; Smoking.

MeSH terms

  • Adolescent
  • Adult
  • Case-Control Studies
  • Databases, Factual
  • Female
  • Humans
  • Infant
  • Infant, Newborn
  • Ontario / epidemiology
  • Pregnancy
  • Pregnancy Outcome / epidemiology*
  • Pregnancy in Adolescence / statistics & numerical data*
  • Retrospective Studies
  • Risk Factors
  • Socioeconomic Factors
  • Young Adult