Intergenerational abortion tendency between mothers and teenage daughters: a population-based cohort study

A teenage woman's sexual health practices may be influenced by her mother's experience. We evaluated whether there is an intergenerational tendency for induced abortion between mothers and their teenage daughters.

We conducted a retrospective population-based cohort study involving daughters born in Ontario between 1992 and 1999. We evaluated the daughters' data for induced abortions between age 12 years and their 20th birthday. We assessed each mother's history of induced abortion for the period from 4 years before her daughter's birth to 12 years after (i.e., when her daughter turned 12 years of age). We used Cox proportional hazard models to estimate a daughter's risk of having an induced abortion in relation to the mother's history of the same procedure. We adjusted hazard ratios (HRs) for maternal age and world region of origin, mental or physical health problems in the daughter, mother- daughter cohabitation, neighbourhood-level rate of teen induced abortion, rural or urban residence, and income quintile.

A total of 431 623 daughters were included in the analysis. The cumulative probability of teen induced abortion was 10.1% (95% confidence interval [CI] 9.8%-10.4%) among daughters whose mother had an induced abortion, and 4.2% (95% CI 4.1%-4.3%) among daughters whose mother had no induced abortion, for an adjusted HR of 1.94 (95% CI 1.86-2.01). The adjusted HR of a teenaged daughter having an induced abortion in relation to number of maternal induced abortions was 1.77 (95% CI 1.69-1.85) with 1 maternal abortion, 2.04 (95% CI 1.91-2.18) with 2 maternal abortions, 2.39 (95% CI 2.19-2.62) with 3 maternal abortions and 2.54 (95% CI 2.33-2.77) with 4 or more maternal abortions, relative to none.

We found that the risk of teen induced abortion was higher among daughters whose mother had had an induced abortion. Future research should explore the mechanisms for intergenerational induced abortion.