MCH Alert: Focus on Infant Mortality

Maternal and Child Health Library

MCH Alert: Focus on Infant Mortality is developed by the Maternal and Child Health Library in collaboration with the National Sudden Infant Death Resource Center. This and past issues are available online at and

February 29, 2008

1. Review Examines Screening for Bacterial Vaginosis in Pregnancy
2. Study Compares Risk Factors for SIDS and Apparent Life-Threatening Events
3. Article Describes the Development and Implementation of a Tool to Screen for Psychosocial Risks
4. Authors Look at the Effects of Late-Preterm Birth and Maternal Medical Conditions on Newborn Morbidity Risk



"New treatment trial data pooled with 2001 report data showed no benefit to screening and treating women who are asymptomatic for bacterial vaginosis if they had a low or average risk for preterm delivery for the outcomes of delivery before 37, 34, or 32 weeks; preterm, premature rupture of membranes; or low birthweight," state the authors of an article published in the February 5, 2008, issue of the Annals of Internal Medicine. Preterm birth rates have increased in the past decade, and strong epidemiologic evidence has suggested an association between bacterial vaginosis and preterm birth. After decades of research and with heightened awareness of measuring potential adverse effects of medications, evidence is emerging that the drug being used to treat bacterial vaginosis may, at some doses and for some populations, be triggering adverse pregnancy outcomes. At the same time, evidence suggests that inherent differences in populations, such as previous pregnancy complications, gestational age, ethnicity, or co-infection, may also influence which women are helped or harmed by screening and treatment for bacterial vaginosis. This review was conducted for the U.S. Preventive Services Task Force (USPSTF) to update its 2001 recommendations by examining the evidence on the value of screening for and treating bacterial vaginosis in reducing adverse pregnancy outcomes for asymptomatic women at low, average, and high risk for preterm delivery.

Relevant studies were identified from searches of Cochrane databases, Ovid MEDLINE, reference lists of other systematic reviews, individuals studies, editorials, reports, and Web sites and by consulting experts. Selected studies included systematic reviews and individual randomized, controlled trials that evaluated screening, treatment, pregnancy outcomes, or adverse effects for asymptomatic women with bacterial vaginosis. Data on the studies' design, sample, setting, demographic characteristics, inclusion and exclusion criteria, diagnostic methods, and risk factors were extracted. Pregnancy outcome data were also abstracted. Relevance and internal validity were evaluated using pre-defined study-quality criteria and rating systems. The researchers performed a series of meta-analyses that included new studies identified from the search, as well as from studies identified from the previous review, to estimate the effect of treatment on preterm delivery (less than 37 weeks, less than 34 weeks, or less than 32 weeks); low birthweight; and preterm, premature rupture of membranes.

The authors found that

"Studies to date of bacterial vaginosis in asymptomatic pregnant women have not provided sufficient numbers or details to identify the specific factors playing the most prominent role for harms or benefits," state the authors. They conclude that "more research is needed to better understand these groups and the conditions under which treatment can be harmful or helpful and to explore relevance to other adverse pregnancy outcomes, including preterm delivery before 34 weeks."

Nygren P, Rongwel F, Freeman M, et al. 2008. Evidence on the benefits and harms of screening and treating pregnant women who are asymptomatic for bacterial vaginosis: An update review for the U.S. Preventive Services Task Force. Annals of Internal Medicine 148(3):220-233. Available at

Readers: The U.S. Preventive Services Task Force Summary of Recommendations and supporting documents are available at



"Although a number of epidemiologic risk factors for ALTE [apparent life-threatening event] seem to be similar to those for SIDS [sudden infant death syndrome], several important differences have emerged," state the authors of an article published in the March 2008 issue of The Journal of Pediatrics. An ALTE is defined as "an episode that is frightening to the observer and characterized by some combination of apnea (central or occasionally obstructive), color change (usually cyanotic or pallid but occasionally etythematous or plethoric), marked change in muscle tone (usually limpness), choking or gagging." ALTEs historically designated as "near-miss for SIDS" have been considered "aborted SIDS" deaths. However, the presumed relationship between ALTEs and SIDS has recently been questioned. The article presents findings from a study to address whether ALTEs are significantly related to SIDS.

Data for the study were drawn from a retrospective examination of 153 cases of infants with an ALTE in the Collaborative Home Infant Monitoring Evaluation (CHIME), a multicenter study conducted between 1994 and 1998 with support from the National Institute for Child Health and Human Development. SIDS studies selected for comparison were population-based, had sizable numbers (more than 100 subjects), and were based on infants who died of SIDS during the same decade that the infants with an ALTE participated in the CHIME study. The following indicators were selected for comparison between CHIME ALTE and SIDS studies: male gender, small for gestational age (SGA; calculated based on weight both at birth and at the time of the ALTE), low birthweight, very low birthweight, multiparity, maternal age 20 or younger, maternal smoking, and infant age less than 2 months at event. The analysis assessed whether the risk of an attribute for infants with an ALTE was significantly different from the risk of the same attribute for infants who died of SIDS.

The authors found that, of the characteristics that differed from the well-established risk factors for SIDS, four stood out:
"The differences warrant assigning ALTEs a separate status from SIDS," conclude the authors. They suggest that "a dissociation of ALTEs and SIDS should promote more adequate research studies of ALTEs in the future."

Esani N, Hodgman JE, Ehsani N, et al. 2008. Apparent life-threatening events and sudden infant death syndrome: Comparison of risk factors. The Journal of Pediatrics 152(3):365-370. Abstract available at

Readers: More information is available from the following MCH Library resources:

- Knowledge Path: Infant Mortality at

- Infant Mortality (bibliography) at

- Infant Mortality Prevention (organizations resource list) at



"The development and successful implementation of a multi-dimensional prenatal screening tool is one key step towards ultimately determining the relationship between specific risk factors and poor birth outcomes," state the authors of an article published in the February 2008 issue of the Journal of Health Care for the Poor and Underserved. Racial disparities in birth outcomes have persisted in the United States for decades. One major effort to reduce racial disparities is the federal Healthy Start initiative, which funds 97 community-based programs designed to reduce infant mortality, low birthweight, and preterm birth through outreach activities, risk screening, health education, and case-management services. However, evaluating the impact of these and other prenatal interventions has been hampered by the lack of clear and consistent definitions of risk, validated screening instruments, and universal screening. The purpose of the study described in this article was to test the feasibility of systematically administering a structured screening interview and protocol for psychosocial risk (the Prenatal Risk Overview [PRO]) to all prenatal clients at community clinics that are involved with the Healthy Start Program in Minneapolis-St. Paul, and to gauge whether the process was acceptable to clients and health professionals. The study also examined the prevalence, co-occurrence, and inter-correlations of self-reported psychosocial factors.

The study sample included 1,386 pregnant women screened between November 2005 and April 2007. Ninety-five percent were women of color; 77% were not married. The PRO screened for the following 13 psychosocial risk factors associated with poor birth outcomes: lack of telephone access, lack of transportation, food insecurity, housing instability, lack of social support, intimate partner violence, other physical/sexual abuse, depression, cigarette smoking, alcohol use, illicit drug use, legal system involvement, and child protection involvement.

The authors found that participants were classified at moderate or high risk for the following risk factors at the following rates:
The authors conclude that "quantifying these relationships [between specific risk factors and poor birth outcomes] better is essential to evaluating the extent to which appropriate and timely psychosocial interventions reduce infant mortality, preterm births, and low birth weights."

Harrison PA, Sidebottom AC. 2008. Systematic prenatal screening for psychosocial risks. Journal of Health Care for the Poor and Underserved 19(1):258-276. Abstract available at

Readers: More information is available from the following MCH Library resources:

- Knowledge Path: Domestic Violence at

- Smoking During Pregnancy (bibliography) at

- Substance Use During Pregnancy (bibliography) at



"Our study findings indicate that the risk for newborn morbidity increases twofold with each earlier week of gestation, beginning at 38 weeks' gestation until 34 weeks' gestation," state the authors of an article published in the February 2008 issue of Pediatrics. Preterm delivery is the most important determinant of neonatal morbidity and mortality in developed countries. Late preterm births (34-36 weeks' gestation) accounted for 74% of all preterm births in 2002. Past research on short- and long-term morbidity among late-preterm infants has been limited, and earlier studies have not comprehensively examined the association between preexisting maternal medical conditions and newborn morbidity among late-preterm infants. In the population-based study described in this article, the authors compared term infants (37-41 weeks' gestation) to late-preterm infants and assessed the independent and joint effects of late-preterm birth and selected maternal medical conditions on the development of newborn morbidity during the birth hospitalization. The authors created a new, high-threshold measure of morbidity using information available via infants' hospital discharge records, including diagnosis, length of hospital stay, and transfer to another facility, as well as mortality available from the infant death certificate. Eight maternal medical conditions were also examined: hypertensive disorders of pregnancy (HDP), diabetes, antepartum hemorrhage, lung disease, infection, cardiac disease, renal disease, and genital herpes.

The authors used a cohort of singleton, late-preterm and term infants born in Massachusetts hospitals to Massachusetts residents. Data available for this analysis were from January 1, 1998, through November 30, 2003. The final study population included 26,170 infants born at 34-36 weeks' gestation and 377,638 infants born at 37-41 weeks' gestation.

The authors found that
The authors conclude that "Because some maternal medical conditions are potentially preventable and/or amenable to treatment, early recognition and better treatment of women with chronic and pregnancy-related health conditions may decrease the rates of newborn morbidity in all infants but especially in late-preterm infants."

Shapiro-Mendoza CK, Tomashek KM, Kotelchuk M, et al. 2008. Effect of late-preterm birth and maternal medical conditions on newborn morbidity risk. Pediatrics 121(2):e223-e232. Available at

Readers: More information is available from the MCH Library's resources:

- Knowledge Path: Preconception and Pregnancy at

- Prematurity (bibliography) at

- Prenatal Care (bibliography) at

- Maternal Morbidity and Mortality (organizations resource list) at

- Prenatal Care (organizations resource list) at


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MCH Alert © 1998-2008 by National Center for Education in Maternal and Child Health and Georgetown University. MCH Alert: Focus on Infant Mortality is produced by Maternal and Child Health Library at the National Center for Education in Maternal and Child Health under its cooperative agreements (U02MC00001 and U48MC08717) with the Maternal and Child Health Bureau, Health Resources and Services Administration, U.S. Department of Health and Human Services. The Maternal and Child Health Bureau reserves a royalty-free, nonexclusive, and irrevocable right to use the work for federal purposes and to authorize others to use the work for federal purposes.
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