Major Congenital Anomaly in Infant Linked to Maternal Death

Laurie Barclay, MD

December 20, 2016

Giving birth to an infant with a major congenital anomaly was associated with a small but statistically significant increased risk for maternal death, a large, population-based cohort study has found.

Eyal Cohen, MD, from the Hospital for Sick Children, University of Toronto, Ontario, Canada, and colleagues report their findings in an article published in the December 20 issue of JAMA.

"[M]others of infants born with a major congenital anomaly had a significantly increased mortality risk compared with women without an affected infant," the researchers write. "This elevated risk was noted both during the first 10 years after the child's birth, when the mother was likely caring for a dependent child with substantial health needs, and after longer follow-up, and no single cause of death explained this association."

However, the investigators note that the absolute mortality rate difference was small (0.33 per 1000 person-years; unadjusted hazard ratio [HR], 1.27 [95% confidence interval, 1.20-1.35], or a 27% increase).

Major congenital anomalies are structural changes, such as cleft palate, with significant medical, social, or cosmetic impact, that usually need medical intervention. In the United States and Europe, prevalence is approximately 2% to 5% of all births. The burden of these anomalies for mothers of affected children include high financial costs and caring for a child with special complex needs within the home.

Although having a child with a major congenital anomaly is clearly recognized as a serious life event, few previous studies have addressed long-term maternal health impact. This study used individual-level linked Danish registry data to examine the association between birth of an infant with a major congenital anomaly and maternal risk for mortality.

Study Details

The study cohort consisted of 41,508 mothers in Denmark who gave birth between 1979 and 2010 to an infant with a major congenital anomaly, as defined by the European Surveillance of Congenital Anomalies. Using random sampling, the researchers constructed a comparison cohort of up to 10 unaffected mothers for each affected mother (n = 413,742), matched for maternal age, parity, and year of infant's birth.

In both groups, mean age at delivery was 28.9 ± 5.1 years. All-cause mortality during follow-up through December 31, 2014, was the primary outcome, and cause-specific mortality was a secondary outcome. Median follow-up was 21 years (interquartile range, 12 - 28 years).

Mortality rate was 1.60 per 1000 person-years for mothers of a child with a major congenital anomaly, and 1.27 per 1000 person-years in the comparison cohort. The absolute mortality rate difference was 0.33 per 1000 person-years (95% confidence interval [CI], 0.24 - 0.42). The unadjusted hazard ratio (HR) was 1.27 (95% CI, 1.20 - 1.35).

After adjustment for marital status, immigration status, income quartile, educational level, diabetes mellitus, modified Charlson comorbidity index, hypertension, depression, alcohol-related disease history, previous spontaneous abortion, pregnancy complications, smoking, and body mass index, adjusted HR for death was 1.22 (95% CI, 1.15 - 1.29).

Mortality risk was higher in mothers of infants with more severe anomalies and in those who had four or more subsequent hospitalizations.

No Single Cause of Death Identified

Cardiovascular mortality was greater among mothers with compared with those without affected infants (rate difference, 0.05 per 1000 person-years [95% CI, 0.02 - 0.08]; adjusted HR, 1.26 [95% CI, 1.04 - 1.53]). So was respiratory disease mortality (rate difference, 0.02 per 1000 person-years [95% CI, 0.00 - 0.04]; adjusted HR, 1.45; 95% CI, 1.01 - 2.08) and mortality from other natural causes (rate difference, 0.11 per 1000 person-years [95% CI, 0.07 - 0.15]; adjusted HR, 1.50 [95% CI, 1.27 - 1.76]).

Cancer mortality was only marginally increased (rate difference, 0.06 per 1000 person-years [95% CI, 0.00 - 0.12]; adjusted HR, 1.11 [95% CI, 1.00 - 1.22]).

Despite the small, statistically significantly increased mortality risks in mothers of affected infants, the researchers note that "the clinical importance of this association is uncertain."

Previous research has shown increased mortality among bereaved caregiving mothers and high rates of chronic stress among nonbereaved mothers caring for chronically ill children. The latter studies were limited by small size but showed poor self-reported health outcomes or advanced cellular aging biomarkers.

In this study, mortality from diseases most closely linked to chronic stress exposure, particularly cardiovascular diseases, was higher among mothers of affected children.

Limitations of this study include possible unmeasured confounding and lack of generalizability to other populations.

The authors have disclosed no relevant financial relationships.

JAMA. 2016;316(23):2515-2524. Abstract

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