Teen pregnancy tied to future premature mortality, large study shows

"Premature death risk was 1.9 per 10 000 person-years among girls without a pregnancy, 4.1 per 10 000 person-years among those with one pregnancy, and 6.1 per 10 000 person-years among those with two or more pregnancies," the researchers reported.

The study stated, "Apparent protective factors for preventing adolescent pregnancy include school and peer support, a stable family, open communication with adult mentors or parents about contraception use, female empowerment to abstain from unwanted or unplanned intercourse, and free access to contraception." 

Suicide, unintentional injury, and homicide are the main causes of death among young females. Teen pregnancy may be a marker of adverse life experiences. Joel G. Ray, University of Toronto, Toronto, Ontario, Canada, and colleagues aimed to evaluate the risk of premature mortality from 12 years of age onward in association with the number of teen pregnancies and age at pregnancy.

For this purpose, the researchers conducted a population-based cohort study among all females alive at 12 years of age from 1991 to 2021, in Ontario, Canada. The study period ended on March 31, 2022.

The main exposure was the number of teen pregnancies between 12 and 19 years (0, 1, or ≥2). Secondary exposures included how the pregnancy ended (miscarriage or birth versus induced abortion) and age at first teen pregnancy.

The primary outcome was all-cause mortality starting at 12 years of age. Hazard ratios (HRs) were adjusted for comorbidities at 9 to 11 years of age, year of birth, and area-level education, rurality, and income level.

The study led to the following findings:

• Of 2 242 929 teenagers, 7.3% experienced a pregnancy at a median age of 18 years.
• Of those with a teen pregnancy, 36.8% ended in a birth (of which 99.1% were live births), and 65.1% ended in induced abortion.
• The median age at the end of follow-up was 25 years (IQR, 18-32 years) for those without a teen pregnancy and 31 years (IQR, 25-36 years) for those with a teen pregnancy.
• There were 6030 deaths (1.9 per 10 000 person-years) among those without a teen pregnancy, 701 deaths (4.1 per 10 000 person-years) among those with 1 teen pregnancy, and 345 deaths (6.1 per 10 000 person-years) among those with 2 or more teen pregnancies; adjusted HRs (AHRs) were 1.51 for those with 1 pregnancy and 2.14 for those with 2 or more pregnancies.
• Comparing those with versus without a teen pregnancy, the AHR for premature death was 1.25 from noninjury, 2.06 from unintentional injury, and 2.02 from intentional injury.

In conclusion, the findings showed that teen pregnancy is associated with future premature mortality.

"It should be assessed whether support for female teenagers who experience pregnancy can enhance the prevention of subsequent premature mortality in young and middle adulthood," the researchers wrote.

Reference:

Ray JG, Fu L, Austin PC, et al. Teen Pregnancy and Risk of Premature Mortality. JAMA Netw Open. 2024;7(3):e241833. doi:10.1001/jamanetworkopen.2024.1833