TY - JOUR

T1 - Shared risk aversion in spontaneous and induced abortion

AU - Catalano, Ralph

AU - Bruckner, Tim A.

AU - Karasek, Deborah

AU - Adler, Nancy E.

AU - Mortensen, Laust H.

N1 - © The Author 2016. Published by Oxford University Press on behalf of the European Society of Human Reproduction and Embryology. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

PY - 2016/5

Y1 - 2016/5

N2 - STUDY QUESTION: Does the incidence of spontaneous abortion correlate positively over conception cohorts with the incidence of non-clinically indicated induced abortion as predicted by shared risk aversion?SUMMARY ANSWER: We find that the number of spontaneous and non-clinically indicated induced abortions correlates in conception cohorts, suggesting that risk aversion affects both the conscious and non-conscious mechanisms that control parturition.WHAT IS KNOWN ALREADY: Much literature speculates that natural selection conserved risk aversion because the trait enhanced Darwinian fitness. Risk aversion, moreover, supposedly influences all decisions including those that individuals can and cannot report making. We argue that these circumstances, if real, would manifest in conscious and non-conscious decisions to invest in prospective offspring, and therefore affect incidence of induced and spontaneous abortion over time.STUDY DESIGN, SIZE, DURATION: Using data from Denmark, we test the hypothesis that monthly conception cohorts yielding unexpectedly many non-clinically indicated induced abortions also yield unexpectedly many spontaneous abortions. The 180 month test period (January 1995 through December 2009), yielded 1 351 800 gestations including 156 780 spontaneous as well as 233 280 induced abortions 9100 of which were clinically indicated.PARTICIPANTS/MATERIALS, SETTING, METHODS: We use Box-Jenkins transfer functions to adjust the incidence of spontaneous and non-clinically indicated induced abortions for autocorrelation (including seasonality), cohort size, and fetal as well as gestational anomalies over the 180-month test period. We use cross-correlation to test our hypothesized association.MAIN RESULTS AND THE ROLE OF CHANCE: We find a positive association between spontaneous and non-clinically indicated induced abortions. This suggests, consistent with our theory, that mothers of conception cohorts that yielded more spontaneous abortions than expected opted more frequently than expected for non-clinically indicated induced abortion.LIMITATIONS, REASONS FOR CAUTION: Limitations of our work include that even the world's best registration system will not capture all spontaneous abortions and that results may not generalize beyond Denmark.WIDER IMPLICATIONS OF THE FINDINGS: Our findings imply that abortion, intentional or 'spontaneous,' follows from a woman's estimate, made consciously or otherwise, of the costs and benefits of extending gestation given characteristics of the prospective offspring, likely environmental circumstances at birth, and maternal resources.STUDY FUNDING/COMPETING INTERESTS: The Robert Wood Johnson Health and Society Scholars Program funded the research described in this manuscript. None of the authors has any conflict of interest to declare.

AB - STUDY QUESTION: Does the incidence of spontaneous abortion correlate positively over conception cohorts with the incidence of non-clinically indicated induced abortion as predicted by shared risk aversion?SUMMARY ANSWER: We find that the number of spontaneous and non-clinically indicated induced abortions correlates in conception cohorts, suggesting that risk aversion affects both the conscious and non-conscious mechanisms that control parturition.WHAT IS KNOWN ALREADY: Much literature speculates that natural selection conserved risk aversion because the trait enhanced Darwinian fitness. Risk aversion, moreover, supposedly influences all decisions including those that individuals can and cannot report making. We argue that these circumstances, if real, would manifest in conscious and non-conscious decisions to invest in prospective offspring, and therefore affect incidence of induced and spontaneous abortion over time.STUDY DESIGN, SIZE, DURATION: Using data from Denmark, we test the hypothesis that monthly conception cohorts yielding unexpectedly many non-clinically indicated induced abortions also yield unexpectedly many spontaneous abortions. The 180 month test period (January 1995 through December 2009), yielded 1 351 800 gestations including 156 780 spontaneous as well as 233 280 induced abortions 9100 of which were clinically indicated.PARTICIPANTS/MATERIALS, SETTING, METHODS: We use Box-Jenkins transfer functions to adjust the incidence of spontaneous and non-clinically indicated induced abortions for autocorrelation (including seasonality), cohort size, and fetal as well as gestational anomalies over the 180-month test period. We use cross-correlation to test our hypothesized association.MAIN RESULTS AND THE ROLE OF CHANCE: We find a positive association between spontaneous and non-clinically indicated induced abortions. This suggests, consistent with our theory, that mothers of conception cohorts that yielded more spontaneous abortions than expected opted more frequently than expected for non-clinically indicated induced abortion.LIMITATIONS, REASONS FOR CAUTION: Limitations of our work include that even the world's best registration system will not capture all spontaneous abortions and that results may not generalize beyond Denmark.WIDER IMPLICATIONS OF THE FINDINGS: Our findings imply that abortion, intentional or 'spontaneous,' follows from a woman's estimate, made consciously or otherwise, of the costs and benefits of extending gestation given characteristics of the prospective offspring, likely environmental circumstances at birth, and maternal resources.STUDY FUNDING/COMPETING INTERESTS: The Robert Wood Johnson Health and Society Scholars Program funded the research described in this manuscript. None of the authors has any conflict of interest to declare.

KW - Abortion, Induced

KW - Abortion, Spontaneous

KW - Decision Making

KW - Denmark

KW - Female

KW - Humans

KW - Incidence

KW - Pregnancy

KW - Reproductive Behavior

KW - Journal Article

KW - Research Support, Non-U.S. Gov't

U2 - 10.1093/humrep/dew031

DO - 10.1093/humrep/dew031

M3 - Journal article

C2 - 26965433

VL - 31

SP - 1113

EP - 1119

JO - Human Reproduction

JF - Human Reproduction

SN - 0268-1161

IS - 5

ER -