Abortion legislation, maternal healthcare, fertility, female literacy, sanitation, violence against women and maternal deaths: a natural experiment in 32 Mexican states
To test whether there is an association between abortion legislation and maternal mortality outcomes after controlling for other factors thought to influence maternal health.
Design
Population-based natural experiment.
Setting and Data Sources
Official maternal mortality data from 32 federal states of Mexico between 2002 and 2011.
Main Outcomes
Maternal mortality ratio (MMR), MMR with any abortive outcome (MMRAO) and induced abortion mortality ratio (iAMR).
Independent Variables
Abortion legislation grouped as less (n=18) or more permissive (n=14); constitutional amendment protecting the unborn (n=17); skilled attendance at birth; all-abortion hospitalisation ratio; low birth weight rate; contraceptive use; total fertility rates (TFR); clean water; sanitation; female literacy rate and intimate-partner violence.
Main Results
Over the 10-year period, states with less permissive abortion legislation exhibited lower MMR (38.3 vs 49.6; p<0.001), MMRAO (2.7 vs 3.7; p<0.001) and iAMR (0.9 vs 1.7; p<0.001) than more permissive states. Multivariate regression models estimating effect sizes (β-coefficients) for mortality outcomes showed independent associations (p values between 0.001 and 0.055) with female literacy (β=-0.061 to -1.100), skilled attendance at birth (β=-0.032 to -0.427), low birth weight (β=0.149 to 2.166), all-abortion hospitalisation ratio (β=-0.566 to -0.962), clean water (β=-0.048 to -0.730), sanitation (β=-0.052 to -0.758) and intimate-partner violence (β=0.085 to 0.755). TFR showed an inverse association with MMR (β=-14.329) and MMRAO (β=-1.750) and a direct association with iAMR (β=1.383). Altogether, these factors accounted for (R(2)) 51-88% of the variance among states in overall mortality rates. No statistically independent effect was observed for abortion legislation, constitutional amendment or other covariates.
Conclusions
Although less permissive states exhibited consistently lower maternal mortality rates, this finding was not explained by abortion legislation itself. Rather, these differences were explained by other independent factors, which appeared to have a more favourable distribution in these states.
Enriquez Y et al., 2024·PLOS global public health·Free full text on PubMed Central
This study estimated the effects of the COVID-19 pandemic on maternal mortality in Chile between 2020 and 2021. A natural experiment was conducted using official data on maternal deaths and live births (LBs) between 1997 and 2021. The effects of the SARS-CoV-2 outbreak were evaluated using interrupted time series (ITS) and an autoregressive integrated moving average (ARIMA) model to forecast the expected rates on MMR and 95% confidence intervals (95% CI). In Chile, following World Health Organization suggestions, maternal deaths aggravated by SARS-CoV-2 are assigned to code O98.5 (non-respiratory infectious indirect) accompanied by code U07.1 or U07.2, depending on confirmation of the presence or absence of the virus. ITS analysis revealed that the SARS-CoV-2 outbreak impacted the MMR due to indirect causes, with a greater increase in indirect nonrespiratory causes than respiratory causes. The ARIMA forecast was consistent with ITS, showing that the expected MMR for indirect causes (3.44 in 2020 and 1.55 in 2021) was substantially lower than the observed rates (9.65 in 2020 and 7.46/100.000 LBs in 2021). For nonrespiratory indirect causes, the observed values of the MMR for 2020 (8.77/100.000 LBs) and 2021 (7.46/100.000 LBs) were double the predicted values of 4.02 (95% CI: 0.44-7.61) and 3.83 (95% CI: -0.12-7.79), respectively. A lower effect was observed on direct obstetrical deaths. During 2020-2021, there was a rise in the MMR in Chile attributable to SARS-CoV-2. The pandemic contributed to an escalation in the MMR due to indirect causes, particularly nonrespiratory and infectious causes. MMR due to direct obstetric causes were less affected. This suggests that the pandemic disproportionately affected maternal health by exacerbating conditions unrelated to pregnancy, childbirth, or postpartum, more than those directly linked to obstetric complications.
Critto ME et al., 2021·Lancet regional health. Americas·Free full text on PubMed Central
Emerging pandemic viruses may have multiple deleterious effects on maternal health. This study examines the effects of a pandemic influenza virus on cause-specific maternal mortality time series, using Argentinian vital statistics.
We conducted a population-based natural experiment from national vital records of maternal deaths between 1980 and 2017. Joinpoint regression models were used to model time series of the maternal mortality ratio (MMR). The sensitivity of the registry to detect the effects of the pandemic H1N1 2009 influenza virus on cause-specific MMR was analysed using a panel of parallel interrupted time series (ITS).
Over this 38-year study, the MMR decreased by 58·6% (69·5 to 28·8 deaths/100,000 live births), transitioning from direct obstetric causes (67·0 to 21·1/100,000 live births; 68·4% decrease) to indirect causes (2·6 to 7·7/100,000 live births; 196·2% increase). The regression analysis showed an average reduction of -2·2%/year (95% CI: -2·9 to -1·4) with 2 join points in the total trend (1998 and 2009). Parallel ITS analyses revealed the pandemic H1N1 virus had an increasing effect on mortality from the respiratory system- and sepsis-related complications (level change 4·7 and 1·6/100,000 live births respectively), reversing after the outbreak. No effect was found on MMR from hypertensive disorders, haemorrhage, abortive outcomes, other direct obstetric causes, and indirect non-respiratory comorbidities.
The Argentinian maternal death registry appears sensitive to detect different effects of emerging infectious epidemics on maternal health. In a population-based natural experiment, pandemic H1N1 virus impacted maternal mortality almost exclusively from the respiratory system- and sepsis-related complications.
Supported by FISAR www.fisarchile.org.
Harrison D et al., 2018·Linacre Q·Free full text on PubMed Central
The purpose of this review was to determine whether there is evidence that ovulation can occur in women using hormonal contraceptives and whether these drugs might inhibit implantation. We performed a systematic review of the published English-language literature from 1990 to the present which included studies on the hormonal milieu following egg release in women using any hormonal contraceptive method. High circulating estrogens and progestins in the follicular phase appear to induce dysfunctional ovulation, where follicular rupture occurs but is followed by low or absent corpus luteum production of progesterone. Hoogland scoring of ovulatory activity may inadvertently obscure the reality of ovum release by limiting the term "ovulation" to those instances where follicular rupture is followed by production of a threshold level of luteal progesterone, sufficient to sustain fertilization, implantation, and the end point of a positive β-human chorionic gonadotropin. However, follicular ruptures and egg release with subsequent low progesterone output have been documented in women using hormonal contraception. In the absence of specific ovulation and fertilization markers, follicular rupture should be considered the best marker for egg release and potential fertilization. Women using hormonal contraceptives may produce more eggs than previously described by established criteria; moreover, suboptimal luteal progesterone production may be more likely than previously acknowledged, which may contribute to embryo loss. This information should be included in informed consent for women who are considering the use of hormonal contraception. For this study, the authors looked at English-language research articles that focused on how hormonal birth control, such as the birth control pill, may affect very early human embryos. The authors found that abnormal ovulation, or release of an egg followed by abnormal hormone levels, may often occur in women using hormonal birth control. This may increase the number of very early human embryos who are lost before a pregnancy test becomes positive. For women who are thinking about using hormonal birth control, this is important information to consider.
Policy and Regulation · Access and Coverage Policy
Mortality by abortion has continuously decreased over the past fifty years in Chile. In fact, maternal death as a result of an induced abortion has become an exceptionally rare phenomenon in epidemiological terms (a risk of 1 in 4 million pregnant women of fertile age or 0.4 per 100,000 life births for abortion of any type, excluding ectopic pregnancy). After abortion became illegal in 1989, deaths related to abortion continued to decrease from 10.8 to 0.39 per 100,000 live births. This scientific fact challenges the common notion that less permissive abortion laws lead to greater mortality associated with abortion.
Related research
Policy and Regulation · Access and Coverage Policy
Koch E, 2013·The Linacre quarterly·Free full text on PubMed Central
Improving maternal health and decreasing morbidity and mortality due to induced abortion are key endeavors in developing countries. One of the most controversial subjects surrounding interventions to improve maternal health is the effect of abortion laws. Chile offers a natural laboratory to perform an investigation on the determinants influencing maternal health in a large parallel time-series of maternal deaths, analyzing health and socioeconomic indicators, and legislative policies including abortion banning in 1989. Interestingly, abortion restriction in Chile was not associated with an increase in overall maternal mortality or with abortion deaths and total number of abortions. Contrary to the notion proposing a negative impact of restrictive abortion laws on maternal health, the abortion mortality ratio did not increase after the abortion ban in Chile. Rather, it decreased over 96 percent, from 10.8 to 0.39 per 100,000 live births. Thus, the Chilean natural experiment provides for the first time, strong evidence supporting the hypothesis that legalization of abortion is unnecessary to improve maternal health in Latin America.
Koch E et al., 2012·PloS one·Free full text on PubMed Central
The aim of this study was to assess the main factors related to maternal mortality reduction in large time series available in Chile in context of the United Nations' Millennium Development Goals (MDGs).
Time series of maternal mortality ratio (MMR) from official data (National Institute of Statistics, 1957-2007) along with parallel time series of education years, income per capita, fertility rate (TFR), birth order, clean water, sanitary sewer, and delivery by skilled attendants were analysed using autoregressive models (ARIMA). Historical changes on the mortality trend including the effect of different educational and maternal health policies implemented in 1965, and legislation that prohibited abortion in 1989 were assessed utilizing segmented regression techniques.
During the 50-year study period, the MMR decreased from 293.7 to 18.2/100,000 live births, a decrease of 93.8%. Women's education level modulated the effects of TFR, birth order, delivery by skilled attendants, clean water, and sanitary sewer access. In the fully adjusted model, for every additional year of maternal education there was a corresponding decrease in the MMR of 29.3/100,000 live births. A rapid phase of decline between 1965 and 1981 (-13.29/100,000 live births each year) and a slow phase between 1981 and 2007 (-1.59/100,000 live births each year) were identified. After abortion was prohibited, the MMR decreased from 41.3 to 12.7 per 100,000 live births (-69.2%). The slope of the MMR did not appear to be altered by the change in abortion law.
Increasing education level appears to favourably impact the downward trend in the MMR, modulating other key factors such as access and utilization of maternal health facilities, changes in women's reproductive behaviour and improvements of the sanitary system. Consequently, different MDGs can act synergistically to improve maternal health. The reduction in the MMR is not related to the legal status of abortion.
Koch E et al., 2012·International journal of women's health·Free full text on PubMed Central
In countries where induced abortion is legally restricted, as in most of Latin America, evaluation of statistics related to induced abortions and abortion-related mortality is challenging. The present article reexamines recent reports estimating the number of induced abortions and abortion-related mortality in Mexico, with special reference to the International Classification of Diseases (ICD). We found significant overestimations of abortion figures in the Federal District of Mexico (up to 10-fold), where elective abortion has been legal since 2007. Significant overestimation of maternal and abortion-related mortality during the last 20 years in the entire Mexican country (up to 35%) was also found. Such overestimations are most likely due to the use of incomplete in-hospital records as well as subjective opinion surveys regarding induced abortion figures, and due to the consideration of causes of death that are unrelated to induced abortion, including flawed denominators of live births. Contrary to previous publications, we found important progress in maternal health, reflected by the decrease in overall maternal mortality (30.6%) from 1990 to 2010. The use of specific ICD codes revealed that the mortality ratio associated with induced abortion decreased 22.9% between 2002 and 2008 (from 1.48 to 1.14 deaths per 100,000 live births). Currently, approximately 98% of maternal deaths in Mexico are related to causes other than induced abortion, such as hemorrhage, hypertension and eclampsia, indirect causes, and other pathological conditions. Therefore, only marginal or null effects would be expected from changes in the legal status of abortion on overall maternal mortality rates. Rather, maternal health in Mexico would greatly benefit from increasing access to emergency and specialized obstetric care. Finally, more reliable methodologies to assess abortion-related deaths are clearly required.
Family Planning Use and Attitudes · Method Use and Prevalence
Rodriguez D et al., 2012·Linacre Q·Free full text on PubMed Central
Hispanics are the largest minority group in the U.S. and they contribute to over 50 percent of Catholics under the age of 25. The purpose of this study was to determine the patterns of contraceptive use (current and ever), natural family planning (NFP), and abortion among U.S. Hispanic women between the ages of 15 and 44 years and to compare their patterns of use to non-Hispanic women of the same age range. A particular interest was to determine the influence of faith on the choice of family-planning methods among the sexually active U.S. Catholic Hispanic women. Data for this study came from the National Survey of Family Growth 2006-2008, which included 1,613 Hispanic and 5,743 non-Hispanic women between the ages of 15 and 44. Approximately 57 percent of the Hispanic women are Catholic. In general, U.S. Hispanic women had significantly less frequent use of the hormonal pill, male condom, withdrawal, and vasectomy (of male partner) but more frequent use of the IUD and Depo-Provera compared to non-Hispanic women. There was little use of NFP and no difference in the frequency of reported abortion. Catholic Hispanic women had significantly less frequent use of the male condom, the Pill, vasectomy, and abortion and more use of NFP compared to non-Catholic Hispanic women. Although there is some positive influence of faith among the sexually active Hispanic women of reproductive age, overall, the amount of ever use of sterilization (21 percent), condom use (80 percent), Pill use (66 percent), and Depo-Provera (30 percent) is remarkable. The more frequent use of Depo-Provera and the IUD might reflect the economic level of the participants and the use of federally funded family-planning services.
Ethics and Policy › Policy and Regulation › Access and Coverage Policy
Elard Koch, Monique Chireau, Fernando Pliego, Joseph Stanford, Sebastian Haddad, Byron Calhoun, Paula Aracena, Miguel Bravo, Sebastián Gatica, John Thorp
E Koch, M Chireau, F Pliego, Joe Stanford, Joey Stanford, J Stanford, S Haddad, B Calhoun, P Aracena, M Bravo, S Gatica, Jack Thorp, J Thorp
PMID 25712817 25712817 DOI 10.1136/bmjopen-2014-006013 10.1136/bmjopen-2014-006013 Koch et al. 2015, Koch 2015
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