Pregnancy associated death in record linkage studies relative to delivery, termination of pregnancy, and natural losses: A systematic review with a narrative synthesis and meta-analysis

Abstract

Objectives: Measures of pregnancy associated deaths provide important guidance for public health initiatives. Record linkage studies have significantly improved identification of deaths associated with childbirth but relatively few have also examined deaths associated with pregnancy loss even though higher rates of maternal death have been associated with the latter. Following PRISMA guidelines we undertook a systematic review of record linkage studies examining the relative mortality risks associated with pregnancy loss to develop a narrative synthesis, a meta-analysis, and to identify research opportunities.

Methods: MEDLINE and SCOPUS were searched in July 2015 using combinations of: mortality, maternal death, record linkage, linked records, pregnancy associated mortality, and pregnancy associated death to identify papers using linkage of death certificates to independent records identifying pregnancy outcomes. Additional studies were identified by examining all citations for relevant studies.

Results: Of 989 studies, 11 studies from three countries reported mortality rates associated with termination of pregnancy, miscarriage or failed pregnancy. Within a year of their pregnancy outcomes, women experiencing a pregnancy loss are over twice as likely to die compared to women giving birth. The heightened risk is apparent within 180 days and remains elevated for many years. There is a dose effect, with exposure to each pregnancy loss associated with increasing risk of death. Higher rates of death from suicide, accidents, homicide and some natural causes, such as circulatory diseases, may be from elevated stress and risk taking behaviors.

Conclusions: Both miscarriage and termination of pregnancy are markers for reduced life expectancy. This association should inform research and new public health initiatives including screening and interventions for patients exhibiting known risk factors.

Keywords: Maternal mortality; abortion; health policy; longevity; miscarriage; pregnancy associated death; pregnancy loss; pregnancy screening; risk factors; termination of pregnancy.

Figure 1.

Flow chart of search results, reasons for exclusion, and three levels of inclusion.

Figure 2.

Cumulative Age Adjusted, All Cause Mortality Rates per 100,000 Women for One and Two Year Periods Following Pregnancy Outcome.

Figure 3.

Cumulative Age Adjusted, Violent Cause Mortality Rates per 100,000 Women for One and Two Year Periods Following Pregnancy Outcome. *Mortality rates shown were also adjusted for one year pre-pregnancy psychiatric history.

Figure 4.

Death rates following first pregnancy outcome through 180 days and during each of the first through tenth years after pregnancy outcome.

Figure 5.

Adjusted odds ratios for pregnancy associated long-term mortality by exposure to types of pregnancy outcomes. Adjusting for age at last pregnancy and number of pregnancies.

Figure 6.

Adjusted Odds Ratios for Pregnancy Associated Long Term Mortality Rates by Frequency of Exposure to Each Pregnancy Outcome—Denmark 1980–2004. Group 1. The odds ratios for exposure to abortion are adjusted for age at last pregnancy, number of births and number of natural losses. Group 2. The odds ratios for exposure to natural loss are adjusted for age at last pregnancy, number of births and number of abortions. Group 3. The odds ratios for exposure to birth are adjusted for age at last pregnancy, number of natural losses and number of abortions. All data from Table 4 of Coleman PK et al.

Figure 7.

Meta-Analysis of Age Adjusted One Year Mortality Rates Associated with Comparative Pregnancy Outcomes.

Figure 8.

Rate of treatments for attempted suicide before and after delivery or TOP.