Reducing Maternal Morbidity and Mortality in the USA

Approach to Prevention of Maternal Mortality: Severe Maternal Morbidity

To better understand how to reduce maternal death, it is important to consider death in the context of a continuum of maternal health from wellness to morbidity to severe morbidity to death.^[14] Presumably, women who die move through this continuum, and thus the question is, can progression from wellness to severe maternal morbidity to death be reduced to result in improved maternal outcomes. It is well accepted that far more women have severe morbidity than die in pregnancy. In fact, several studies have estimated that severe maternal morbidity may occur at a rate of 0.5–1.3% of pregnancies accounting for up to 50,000 women per year in the USA.^[15,16] Severe maternal morbidity was identified by using ICD-9 codes including codes for acute renal failure, cardiac arrest, sepsis, shock, disseminated intravascular coagulation, myocardial infarction, transfusion, ventilation, pulmonary edema and eclampsia. More evidence that severe maternal morbidity is on the continuum to maternal death is that in conjunction with an increase in maternal death in the USA, severe maternal morbidity has also increased between 1998 and 2011 from 0.6% deliveries to 1.6%.^[16] If women with severe maternal morbidity have similar characteristics as women who die, then evaluating women with severe morbidity to understand their disease process, presence of preventable factors and outcomes should result in data useful in reducing morbidity and progression to death.

Early studies used the concept of near miss to define women that were extremely sick but did not die and asked whether these women had similar characteristics to those who died.^[17,18] Intensive care unit (ICU) admission or transfusion of four or more units of blood had a high sensitivity and specificity for identifying women with near-miss morbidity.^[17,19] In one study 40% of maternal deaths and 45% of near-miss cases had preventable factors compared with only 17% of cases with less morbidity (p = 0.01), supporting the concept that there is a continuum between very sick women and women who died.^[14] As with maternal deaths, provider and system preventable factors were far more common than patient preventable factors in women with near-miss morbidity.^[13,14] These data are important because they begin to focus our attention in areas to be studied which could ultimately improve maternal outcomes.