Teenagers more likely to have an abortion if their mother terminated a pregnancy: study

Teenage girls are more likely to have an abortion if their mother has had one according to a new study from the Institute for Clinical Evaluative Sciences (ICES).

The study published today in CMAJ is the first to look at the relationship of intergenerational abortions. Using secure patient health records housed at ICES on mother-daughter pairs, the researchers looked at the records of 431,623 daughters born in 1992 to 1999 and evaluated if they had an abortion between the ages of 12 to 19. The researchers then looked at the mothers’ history with abortion four years before their daughter’s birth until their daughter turned 12-years-old.

“We know that there is an intergenerational cycle of teenage motherhood, in fact, the relationship between mother and daughter influences the age when a daughter gets pregnant and has her first child. We wanted to see if there was the same association around abortion between a mother and her daughter,” says Dr. Joel Ray, senior author on the study and a researcher at ICES.

The researchers evaluated 73,518 daughters whose mothers had had at least one abortion and 358,105 daughters whose mothers had none. In the group where the mothers had at least one abortion, 4,880 daughters had an abortion during follow-up, equivalent to a cumulative probability of 10.1 per cent during entire teenage years. In the group where the mothers did not have an abortion, 10,108 daughters had an abortion, a cumulative probability of 4.2 per cent. The majority of those abortions (94.5 per cent) occurred before 15 weeks of pregnancy.

In developed countries, approximately 6.7 million abortions are performed every year, with a large proportion among teens aged 19 years or younger. In Canada, the teen pregnancy rate is 28 per 1000, with more than half of these pregnancies ending in abortion.

“While our study can’t answer why this association exists, and we accounted for several factors in our analysis, it shows that a teenage girl is twice as likely to have an abortion if her mother had one. This intergenerational link persisted across different demographic groups, and was more pronounced when a mother had an increasing number of abortions,” says Ning Liu, lead author on the study, senior research analyst at ICES and PhD candidate at University of Toronto.

The investigators add that further research is needed to determine if strategies that engage parents could reduce unprotected sex in teens, as well as to understand the major factors that contribute not only to teen pregnancy, but the decision to have an abortion or maintain a pregnancy.

“Intergenerational abortion tendency between mothers and teenage daughters: population based cohort study,” was published today in CMAJ.

Author block: Ning Liu, Michele Farrugia, Simone Vigod, Marcelo Urquia and Joel Ray.

The Institute for Clinical Evaluative Sciences (ICES) is an independent, non-profit organization that uses population-based health information to produce knowledge on a broad range of healthcare issues. Our unbiased evidence provides measures of health system performance, a clearer understanding of the shifting healthcare needs of Ontarians, and a stimulus for discussion of practical solutions to optimize scarce resources. ICES knowledge is highly regarded in Canada and abroad, and is widely used by government, hospitals, planners, and practitioners to make decisions about care delivery and to develop policy. For the latest ICES news, follow us on Twitter: @ICESOntario

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