This program is brought to you by Emory University. >> Hello, my name is Carol Hogue. I'm a population epidemiologist, Professor of Epidemiology, and I hold the Terry Professorship in Maternal and Child Health at Rollins School of Public Health here at Emory University. I also hold joint appointments in the Behavioral Sciences and Health Education Department as well as in the Department of Pediatrics in the School of Medicine, and the Department of Sociology in Emory college. Before coming to Emory in 1992, I served ten years in the division of reproductive health at the US Centers for Disease Control and Prevention, and I was division director there from 1987 to 1992. The pregnancy mortality surveillance system was one of the ongoing projects that were begun while I was division director. This week we will be reviewing that system in the context of discussing maternal mortality and severe maternal morbidity in the United States. The US is by no measure the safest country in which to give birth, as a number of developed countries have better mortality rates by rank. However, we will discuss why a country's maternal mortality rank may be somewhat misleading. Part of the answer is how maternal mortality is defined, and the various definitions, meanings and interpretations form the first objective for this week. The specific objectives for this week are, first, introduce key terms. We will define maternal mortality, pregnancy related mortality and pregnancy associated mortality. Also we will define direct and indirect causes of death and describe why these distinctions are of increasing importance in the developing world as well as the developed world. Second, we'll explore the heterogeneity of pregnancy-related mortality and severe morbidity in the US, and discuss what may underlie apparent disparities in maternal survival. Third, we'll explore primary prevention modalities. Primary prevention prevents the health condition. Fourth, we'll explore secondary prevention modalities. Secondary prevention does not prevent the health condition but it ameliorates its ill effects. Fifth, we'll present a case example illustrating issues related to pregnant women with chronic health conditions. And sixth, when prevention fails what lessons can be learned to avoid future failures? This is the question that maternal death review committees address. We will outline how they do their work and chat with a member of one such committee. So let's get started. Here are the key definitions. According to the World Health Organization, maternal death is the death of a woman while pregnant or within 42 days of the termination of pregnancy, irrespective of the duration and site of the pregnancy, from any cause related to or aggravated by the pregnancy or its management, but not from accidental or incidental causes. Maternal death by this definition is used in most countries, and it is assumed to be the definition used by all countries when they are being ranked. However that is not necessarily the situation in the United States and in some other developed countries. A cause related to the pregnancy is a direct cause. A cause aggravated by the pregnancy is an indirect cause. This distinction is becoming increasingly important as women with chronic conditions, obesity, and advanced maternal age comprise ever growing numbers of women giving birth. In the United States from 1998 to 2006, overall, pregnancy related mortality doubled, largely owing to increases in indirect causes, which, in this graph, are the top or orange bar. And direct causes other than embolism, hemorrhage, and eclampsia. That is the other direct causes, is the turquoise bar which is the second bar. We will return to this rather shocking finding a little later. But first let's finish with our definitions. CDC defines pregnancy-related mortality as the death of a woman while pregnant or within one year of pregnancy termination, regardless of the duration or site of the pregnancy, from any cause related to or aggravated by the pregnancy or its management, but not from accidental or incidental causes. Now accidental or incidental causes are classified by CDC as pregnancy associated but not pregnancy related. These pregnancy-associated deaths actually amount to about 60 to 70% of all reported deaths within a year of pregnancy. In this definition, any cause related to pregnancy is a direct cause, and any cause aggravated by the pregnancy or its management is an indirect cause. So, the two definitions, that is, CDCs and WHOs, mainly differ by the amount of follow-up time. 42 days for the WHO definition and within one year for the CDC definition. Clearly, the longer the follow-up, the more deaths will be found. In fact, from 1998 to 2003, about ten to 15% of reported pregnancy related deaths in the United States occurred after 42 days and before a year after the pregnancy ended. This graph shows that the different definitions make a substantial difference in reported death statistics. Here you see the maternal mortality rate which is what is generally reported, but the pregnancy related mortality rate is what is generally reported in publications from the United States. More and more developed countries have adopted the CDC definition of pregnancy related death and pregnancy related mortality statistics are the major ones being published for the US. However, the definition of pregnancy related mortality on the WHO website is not the same definition. WHO defines pregnancy related mortality as, the death of a woman while pregnant or within 42 days of termination of pregnancy, irrespective of the cause of death. This isn't the same as the CDC definition in that, only deaths up to 42 days are included, but also, all deaths are included, not just pregnancy related deaths. In fact, CDC does not include these pregnancy associated deaths in its statistics on maternal mortality. So the medical literature may report deaths either as maternal mortality or pregnancy related mortality, but unfortunately authors often don't use the proper terminology in their tables and graphs. So pay attention to how they define those statistics in their methods sections, and recognize that an axis on a graph may not be correctly labelled. Another issue with the literature is the interchangeable use of ratio and rate. The Maternal Mortality Rate, or Ratio, is the maternal deaths per 100,000 live births. The pregnancy-related Mortality Rate, or Ratio, is the pregnancy-related deaths per 100,000 live births. Epidemiologists point out that mortality statistics in this field are ratios, not rates, because the numerators contain deaths of women who died after spontaneous abortion, induced abortion, endotopic pregnancies and stillbirths, as well as those who died after live birth. But the denominators are just the number of live births, and don't include these other pregnancy outcomes. In the United States, induced abortion comprises somewhere between a fifth and a fourth of all recognized conceptions, but only about 3% of pregnancy related deaths. Something to consider is that a true maternal or pregnancy related mortality rate could be analogous to a fertility rate and refer to the number of deaths per 100,000 women of reproductive age. Now if this rate were to be used in comparing across countries, it would take into consideration the impact of pregnancy prevention in determining how many women die because of pregnancy, and thus emphasize the value of family planning in reducing maternal mortality. In our next segment, we will turn our attention to the use of mortality statistics to describe trends and disparities among women in the United States
