The researchers, from the Guttmacher Institute in New York, base their findings on feedback data from almost 9,500 women who had an abortion in 2008 (Abortion Patient Survey), in the light of 11 "disruptive" events, and the links between these, poverty, and contraceptive use.
The disruptive events included job loss, separation, falling behind on rental/mortgage payments, death of a close friend, a serious health problem, a partner being sent to prison and becoming a victim of crime.
Poverty in the US is defined as an annual income before tax of $17,500 for a family of three: in 2008, 13% of US residents met this criterion.
The researchers also carried out in-depth interviews with 49 women seeking abortions to flesh out themes from the feedback data.
Their analysis showed that more than half (57%) of the women who had had an abortion had faced a major life stressor in the preceding year. One in 5 had lost their jobs; one in 6 had separated from their partner; one in 7 had fallen behind on their rental or mortgage payments, while one in 8 had moved several times.
One in 10 had experienced the death of a close friend or had had a baby over the past year. And 7% had been subjected to some form of domestic violence.
Women said that the fall-out from one disruptive event could set up a chain reaction. For example, one woman's grief following the death of her mother kept her from leaving an abusive partner.
A higher proportion of women living in poverty (63%) had experienced at least one such event over the previous year than had affluent women (49%).
One in four women who lived in poverty had lost their job compared with 14% of financially better off women. And a higher proportion of those who were poor had also separated from a partner, fallen into arrears with rental/mortgage payments, moved several times or had given birth.
About half of the women were using contraception in the month they became pregnant, but the in-depth interviews showed that nearly half of these women said that disruptive events interfered with contraceptive use.
The authors point out that women living in poverty made up 42% of the 1.2 million abortions carried out in 2008 in the US, up from 27% of the 1.31 million abortions performed in 2000.
More information: www.jfprhc.bmj.com/lookup/doi/10.1136/jfprhc-2012-100311