Ninth Annual Maternal and Child Health Epidemiology Conference / December 10-12, 2003
DR. WANDA BARFIELD: Thank you, Dr. Fry. Can everyone hear me? Good morning everyone. What I wanted to do is just bring up the importance of fetal deaths with regard to perinatal outcomes. As a new natalogist, were often faced with the care of extremely pre-term infants who are born alive. However, there’s a certain component of pregnancy outcomes that are relatively under recognized and that is that of fetal deaths and particularly for this talk, I wanted to talk about a group of fetal deaths that occur fairly late in pregnancy, and that is those that occur greater than 28 weeks gestation, and as you can see from this slide, late fetal deaths make up just about as many deaths as there are with regard to early neonatal deaths during the pregnancy period. It is also important to note that there are a large number of early fetal deaths that occur as well, but you can see that this is a significant problem. So, late fetal deaths, again just for definition sake, occurs to fetuses that are delivered at or greater than 28 weeks gestation with no signs of life. Again, they account for almost half of all U.S. perinatal deaths and these factors are seldom studied. There is also limited awareness, despite healthy people 20/10 objectives to reduce fetal and perinatal mortality in the United States. Racial disparities in late fetal deaths, just at note, for all pregnancies that occur at 28 weeks gestation or greater, black mothers have three times as many late fetal deaths as early neonatal deaths, while white mothers have 2.3 times as late fetal deaths as early neonatal deaths during this period. However, factors that contribute to racial disparities and late fetal deaths are poorly understood.
Our objectives are to describe racial disparities and late fetal deaths to characterize these late fetal deaths by maternal demographic factors and medical conditions and to recommend prevention strategies to prevent disparities. We used U.S. fetal death and linked birth infant death files from 1995 to 1998 from the National Center for Health Statistics. Our population included late fetal deaths. There were approximately 13,000 that occurred annually, as well as live births, which were about 3.8 million that occurred annually. We did exclude nonresident deliveries, those of unknown gestational ages, which made about two percent of all fetal deaths greater than or equal to 28 weeks and those occurrences to multiple births. The variables that we evaluated included maternal race, maternal age, prenatal care utilization, cigarette use, gestational age and medical conditions and complications of labor and delivery. We define our late fetal mortality rate as the number of late fetal deaths, again that is greater than or equal to 28 weeks gestation per thousand live births plus fetal deaths greater than or equal to 28 weeks. Our analysis include *univerianalysis with rate ratios and 95 percent confidence intervals. Multiverianalysis, because 1995 through 98’ were very similar, we included 1998 data only. We excluded undetermined maternal medical risks and complications, which made up eight percent of late fetal deaths and we used odds ratios with 95 percent confidence in (inaudible).
The next set of slides show our results. For our time period from 1995 to 1998, we can see that the rate of late fetal deaths was lowest among Asian Pacific Islander mothers. Our rate of late fetal deaths was highest among black mothers, and the relative risk for this group was 1.8 when compared to white mothers. For all races the rate of late fetal deaths was 3.3 death per 1000 live births and fetal deaths. This slide, shows rates of late fetal death by maternal death comparing white mothers in the white bars and black mothers in the blue bars. As you can see, that in general over time as mother’s age increases the risk of late fetal death increases with increasing maternal age. However, the ratio with regard to risk is greater for mothers among the older age group with women age 35 to 39 having a two fold risk for black mothers compared to white mothers, and for mothers between ages of 40 and 54 a 1.8 fold risk of late fetal deaths for black mothers compared to white mothers. This shows rates of late fetal deaths by prenatal care initiation grouped by prenatal care within the first trimester, after the first trimester, no prenatal care, or unknown prenatal care. As you can see, the highest risk for late fetal death occurs among women with no prenatal care or unknown prenatal care. However, black women are still have higher rates of late fetal death compared to white mothers.
This slide shows rates of late fetal death by cigarette use and you can see that there is a dose response relationship from those women that do not smoke at all as cigarette consumption increases to over two packs a day. Again, although African-American women tend to smoke less, black women who do smoke have higher rates of late fetal death compared to white mothers. We also looked at rates of late fetal death by gestational age group, and these are categorized by each gestational age category. The highest risk of late fetal death occurs among the earlier gestational ages, however, in this case, black mothers have a slightly lower rate of late fetal death compared to white mothers for the gestational ages between 28 and 36 weeks gestation. We then looked at rates of late fetal deaths by selecting maternal medical conditions, and as you can see, certain medical conditions have a significantly increased risk of late fetal deaths. However, for each category to include anemia, diabetes, chronic hypertension and pregnancy induced hypertension, black mothers have a higher risk of late fetal death compared to whites. We also looked at specific risks of complications of labor and delivery to include abruptual placenta seizures during pregnancy and core prolapse, and again found that black women had higher rates of late fetal death compared to white women. We then created logistic regression models, again this is just for the year 1998 in order to assess contributing factors to the racial disparity in late fetal deaths, and found that when we adjusted for various risk factors, the risk of late fetal death among black women did decrease from an earlier rate of blacks compared to whites from 1.8 to 1.3, and we found that by adjusting by maternal age, prenatal care initiation, tobacco use, gestational age and medical risks and complications that risks for black mothers were lower. However, were not eliminated with regard to racial disparity.
However, it’s important to note that national data does have its limitations. We found that there was incomplete data elements on the fetal death certificate, and rates may be underestimated. Also, there is no cause of death information on the national file to include factors that might explain fetal deaths such as congenital anomalies. Also, it is important to note that there is no time of death information, and this is an important factor and when you’re considering anti-partum versus intra-partum causes of death. Also, potential misclassification may occur when a live warrant infant dies soon after delivery, however, this less likely to occur at higher gestational age groups. In conclusion, late fetal deaths represent a large portion of perinatal deaths in the United States. Late fetal deaths are associated with increased maternal age, maternal smoking, late or no prenatal care, preterm gestation, maternal medical conditions and complications. However, despite adjustment for numerous variables, the risk for late fetal deaths is greater among black mothers. However, this may due because there may be possibly more severe medical complications or conditions, and our model did not adjust for other factors, such as social economic factors and community level factors, fetal disorders, environment and nutrition. From our study, however, we would like to recommend that assessment of pregnancy outcome should include fetal deaths.
We need to use data including fetal deaths for program planning, policy and intervention, for example, using perinatal periods of risk assessment. We also need to include the awareness of fetal deaths, particularly among the general public and health professionals. In a way, fetal deaths are almost not only a tragic event, but one that is often very uncomfortable for people to address. We should also improve the quality of fetal death reporting by developing standard protocols to evaluate fetal deaths and promote systematic maternal, fetal and placental clinical evaluation. We should also encourage the complete reporting of fetal death information. We also need to understand the relative contributions of maternal factors to fetal death. This includes preconceptional health of women and maternal behavioral factors. Also, the linkage of maternal and fetal infant records will help to influence reproductive health history on fetal deaths, for example, understanding interpregnancy interval as a component and a contributor to fetal and infant death. We also need to have effective prevention programs. It is also important for us to conduct ideologic research on the causes of fetal death, and to target our efforts toward the prevention of late fetal deaths through programs and clinical interventions. At this time, I’d also like to acknowledge other members who helped to contribute to this study, particularly Dr. Hani Aktrash. Through his efforts we were able to be successful in this endeavor. Thank you very much.