Innovative models of prenatal care are greatly needed to increase access to and utilization of prenatal care, enhance prenatal care content and effectiveness, and reduce the long-standing racial/ethnic disparities in prenatal care and women's pregnancy and health related outcomes (Institute of Medicine, 2003; U.S.Public Health Service, 1989; Lu & Halfron, 2003; Healy et al., 2006). In the U.S., African American pregnant women and their infants are especially likely to benefit from improved prenatal care as they bear the brunt of the racial/ethnic disparities in health outcomes during pregnancy and the perinatal period. African American women have approximately 2-3 times the national rates of maternal and infant mortality, low birthweight, and prematurity as non-Hispanic whites (Kung et al., 2008; Martin et al., 2007). African American women also are less likely to receive the recommended number of prenatal visits. About 25% to 40% of African American women in the U.S. do not enter prenatal care in the first trimester (Martin et al., 2007). Access to obstetrical care (the full continuum of obstetrical care from prenatal care through post-partum care) has been dramatically reduced for all women across diverse geographical settings ranging from large urban areas to rural areas. Reasons contributing to reduced access include workforce shortages, inadequate reimbursement from insurers to cover cost of care, rising costs of professional liability insurance, and increasing cultural diversity including undocumented pregnant women accessing health care at the time of delivery (Delaware Valley Healthcare Council, 2007; Illinois Department of Public Health, 2008; Wisconsin Hospital Association, 2005). Even when women attend prenatal care, there are wide variations in the content of prenatal care. African American women receive less of the recommended content compared to white women, and receipt of less recommended content has been associated with poorer perinatal outcomes (Kogan et al., 1994); and Latina women reported less health promotion content than African American women (Vonderheid, Montgomery, & Norr, 2003). The current model of prenatal care is insufficient to meet the needs of women of color even for those who enter prenatal care early (Healy, 2006). Improving women's pregnancy and health related outcomes may also improve later health behaviors, potentially contributing to long-term reductions in African American women and other ethnic minority women's disproportionate rates of lifestyle-related conditions such as high blood pressure, stroke, obesity and diabetes (U.S.Department of Health and Human Services, 2007).

Unfortunately, problems with access to and quality of prenatal care are not unique to the U.S. In Japan, the shortage of obstetricians (and midwives) is a very severe social concern. Japanese women's active participation in their own health is expected. Many pregnant women and mothers express a desire to have peers. In general, the average length of a prenatal visit (the time actually see a provider) is very short in Japan. Recently, providers that interact with their patients for more than 5 minutes are obligated to receive a fee.

Gaining in popularity and implemented in about 300 sites in the U.S. and abroad with ethnically, socioeconomically diverse populations since 1995, CenteringPregnancy® (Centering) is a multifaceted model of group prenatal care (Rising, 1998). This innovative group prenatal care model holds promise for improving pregnancy and health related outcomes for women and their infants compared to the current model of individual care. The benefits of Centering are likely greater for those in greatest need, such as socially disadvantaged women (i.e., low-income African American women in the U.S) (Ickovics et al., 2007). Centering is innovative because it fundamentally alters the format of prenatal care for women. In Centering, after an individual first visit (a pregnancy risk assessment) that is the same as that for women in individual care, a group of 8-12 women at similar gestational ages attend 10 two-hour visits together. Group visits are initiated between 12 and 16 weeks gestation through 40-42 weeks gestation. The first four visits occur once a month from the 4th through the 7th months of pregnancy. The last six visits occur biweekly. The last session is frequently a postpartum visit for women who began group visits before 16 weeks gestation. This provides an opportunity for postpartum women to share their labor and delivery experiences.

Centering draws on the holistic nurse-midwifery philosophy (Rising, Kennedy, & Klima, 2004; Rising, 1998) and incorporates successful strategies identified in the literature as effective in changing behavior including: increased time for in-depth discussion of health promotion issues, enhanced peer support, a power sharing provider-client relationship, and self-management skill-development that promotes empowerment and self-efficacy for behavior change. Centering differs from individual care in four key components that are intertwined and mutually reinforcing (Rising, Kennedy, & Klima);

• Group discussion of health promotion, with substantially more time for health promotion (approximately 15 hours versus less than 3 hours, assuming 90 minutes per Centering session and 15 minutes of health promotion per individual care return visit).
• Peer group support, through repeated interactions and group discussions with other pregnant women attending the same neighborhood prenatal care clinic.
• A collaborative provider-client partnership based on a feminist approach to health care (Andrist, 1997).
• Self-management training and activities with emphasis on maintaining a record and observing changes over time.

The synergy of these four components of Centering should be more effective than each in isolation.

In contrast to Centering, individual care provides very brief visits (about 15 minutes) with little time for coverage of recommended health promotion content or patient-provider interaction. Women have no opportunity to engage in self-care activities or sharing with other pregnant women. At each visit, ancillary staff take the woman's blood pressure and weight. She then sees the provider (e.g., certified nurse-midwife, physician), has a physical assessment, and any client questions are answered. Certified nurse-midwives typically provide more education and counseling than physicians (Oakley et al., 1995; Vonderheid, Norr & Handler, 2007; Yankou, 1993). In addition, women may be referred for health promotion from nurses, dietitians and other clinic staff.

In Centering, at each visit during the first 30 minutes, women engage in self-management activities that include taking and documenting their own weight and blood pressure, and gestational age; and completing self-assessment sheets related to the core health promotion content of each visit to stimulate discussion. After each woman completes her self-assessment, she has a brief individual prenatal risk assessment (e.g., fundal height, heart tones) with the prenatal provider (certified nurse-midwife, physician) in an area within the group space. If needed, private examination rooms are used for medical concerns requiring privacy such as cervical and vaginal assessments. Women also socialize and enjoy healthy snacks during this time. The next 90 minutes is health promotion education and discussion facilitated by the prenatal provider and co-facilitator (an assistant also trained in facilitative leadership). Each session has an overall plan with "core" health promotion content consistent with the content recommended by the U.S. Public Health Service Expert Panel on the Content of Prenatal Care and professional standards, and content is relevant to the stage of pregnancy of each visit, but any concerns women express are also discussed. Thus, each visit has an overall plan with attention given to selected "core" health promotion content. However, the degree of emphasis varies and additional content is discussed depending on the concerns of women in the group. Centering group visits are highly interactive with extensive use of multiple learning formats: discussion, interactive games, activities (e.g., word puzzles, worksheets) and videos. Invited resource persons (e.g., nutritionist, lactation consultant) share their expertise. The physical environment is made as comfortable as possible and the space is designated as private. Chairs are arranged in a circle to facilitate discussion. Involvement of family support persons at visits is encouraged, and some women are accompanied by family members and friends.

Centering group visits are conducted by two persons trained in facilitative leadership. The prenatal provider (eg., certified nurse-midwife, physician) is typically the lead facilitator responsible for education and facilitation of the group process as well as management of low risk pregnancy and referral for problems. The co-facilitator often prepares the group space (setting-up educational packets, the room, and refreshments), welcomes women on arrival and assists women with the self-management activities (e.g., taking blood pressure, weights, recording information) until women independently complete these activities. The co-facilitator is also responsible for facilitating group process and answering any questions women might have when completing their self-assessments. To ensure continuity, facilitators follow the same groups throughout the 10 visits.

Despite its increasing popularity, few studies evaluated Centering. Thus far, five studies of Centering have been published and a sixth study is in press. Rising described the initial development of Centering and found high rates of prenatal care utilization; low rates of preterm delivery and low birth weight; fewer emergency visits in the third trimester compared to a convenient comparison group; and high satisfaction with Centering among patients and providers (Rising, 1998). A more rigorous study used a prospective matched cohort design and found a small but statistically significant increase (3228.2 versus 3159.1, p<.01) in birth weight for Centering infants compared to individual care infants (Ickovics, et al., 2003). A study with adolescents found that Centering participants had lower preterm birth and low birth weight rates compared to retrospective and concurrent convenient comparison groups (Grady & Bloom, 2004). Centering teens also had higher rates of breastfeeding, had fewer missed appointments, and were more likely to attend a postpartum visit and identify a pediatrician for their infants. Additionally, Centering teens had high satisfaction with group care. In a pretest-posttest design study using a convenience sample, women in Centering groups had significantly higher prenatal knowledge scores in the posttest (Baldwin, 2006). The only randomized controlled trial of Centering conducted compared the outcomes of three groups: Centering, enhanced Centering (focused on HIV/STD prevention), and individual care (control group) (Ickovics, et al., 2007). This clinical trial included African-American, Latina and White women and found that Centering groups had a 33% reduction in preterm birth as well as significant improvements in breastfeeding initiation and maternal prenatal knowledge. Participants in Centering were significantly more satisfied with their care, and were more prepared for labor and delivery. Among African Americans, group participants realized even greater benefits from Centering with a 41% reduction in preterm births compared to African Americans attending individual care. A study of the productivity and cost of Centering found that it was more productive (could serve twice as many women) and reduced costs in the setting studied (Cox, 2006). These studies have focused on low-obstetrical risk women and some studies have included women at risk of adverse outcome related to sociodemographic factors such as low-socioeconomic status and ethnic minority status.

A member of our research team, Dr. Carrie Klima, is one of the early adoptors of Centering, a member of the Board of Directors of the Centering Healthcare Institute, and national trainer. She established the first Centering sites in Chicago. Our team implemented and evaluated Centering in a large public health clinic in Chicago, Illinois serving disadvantaged African American women and their families. We evaluated the feasibility and acceptability of Centering by staff and clients, as well as, examined maternal and infant outcomes (Klima, Norr, Vonderheid, & Handler, in press). Data collection used focus groups with staff (clinical and administrative), self-administered questionnaires with women in groups, and medical record review for utilization and perinatal data. Based on content analysis of focus group interview data, staff described Centering participants as being more independent, taking the initiative to self-schedule missed visits, and being more involved in their prenatal care as well as their infants' pediatric care. These behaviors suggest group participants feel more empowered and are consistent with other studies of group prenatal care that showed more knowledge related to pregnancy (Baldwin, 2006; Ickovics et al., 2007), feeling prepared for labor and delivery (Hoyer, 1994; Ickovics et al., 2007) and having a more positive self-concept (Hoyer, 1994; Ford et al., 2001). In our project, clinic staff also reported that group care participants: are more informed about themselves and their health by interacting with one another, are highly satisfied with group care, want to come to prenatal care, and recommend group care to their friends. Group participants were perceived as bonding with each other and having camaraderie. Centering was viewed as "group rap" that allowed participants to talk and let go of their thoughts and ideas in a safe environment. Prenatal providers were seen (by themselves and other clinic staff) as facilitators of discussion allowing the group prenatal care participants to elaborate on topics they were interested in. One staff member described Centering as "discovery learning" that was reinforced by the group. When returning to the clinic following the birth of the infant, group participants were described as being more involved in the pediatric care, having better communication with the care providers, and were more likely to seek out clinic resources since group care participants "hear more about what resources" the clinic offers. Additionally, prenatal providers indicated that they enjoyed providing group care. They liked "discussing" health promotion content with a group of women and learned information about their patients that might not otherwise have been expressed during an individual care visit. Providers also found group visits more efficient and professionally satisfying than repeating similar information to each woman individually. Regarding perinatal health outcomes, trends found higher mean gestational age and fewer low birth weight infants among Centering participants; however, differences were not statistically significant. Our sample size limited our power to detect differences between groups in these outcomes. Compared to women in individual care, women in Centering had more prenatal visits and higher weight gain during pregnancy, breast feeding rates, and satisfaction (Klima, Norr, Vonderheid, & Handler, in press). Taken together, the six studies of Centering suggest that this group model of prenatal care has a positive impact on pregnancy and health related outcomes in women having low-medical risk pregnancies.

Our research team also developed a process evaluation tool to evaluate fidelity of the Centering intervention and measures of intermediate maternal outcomes (knowledge, self-efficacy, and health behaviors related to pregnancy, post-partum and infant care; and pregnancy-related empowerment) appropriate for low-literacy African American and Latina women (English and Spanish speakers). These outcome measures are needed to examine the pathways by which Centering might affect more distal outcomes of prenatal care, such as perinatal and post-partum outcomes. Our two-component process evaluation (one form for an independent observer of group visits and another for providers/facilitators to complete) documents the fidelity of implementing Centering consistent with the national training program. The process evaluation tool will help providers improve the delivery of Centering and will support rigorous research to test the effectiveness of Centering at improving maternal and infant outcomes. This process evaluation tool is currently used by the Centering Healthcare Institute's site approval process to help identify a site's strengths and challenges.

In conclusion, there is widespread recognition of the need for innovative models of prenatal care to improve access to and quality of prenatal care while limiting costs. Centering is a promising strategy to improve access to and quality of prenatal care, and reduce adverse maternal and infant outcomes, especially among vulnerable populations at greatest risk. Centering represents a major restructuring of prenatal care that can improve the efficiency of service delivery, and improve satisfaction with care by providers and patients. Providers who are more satisfied with their work are likely more willing to remain in the workforce compared to a provider that is not satisfied. While evidence suggests that Centering favorably impacts pregnancy and health related outcomes for women, further evidence is needed about its effect on long-term maternal health behaviors such as lifestyle and parenting. If Centering is consistently shown to be effective, expansion of Centering is a potentially important part of an overall global strategy to reshape the format of prenatal, with the potential for substantial reduction in health care costs by improving the efficiency of prenatal care delivery and reducing the costs associated with prematurity and other adverse maternal and infant outcomes, especially among disadvantaged populations. Centering offers an opportunity to make major improvements in care that both women and providers in Japan and other nations deserve.

Additional information about CenteringPregnancy® and the essential elements of "Centering" care can be found at http://www.centeringhealthcare.org. The Centering Healthcare Institute is an outgrowth of the CenteringPregnancy and Parenting Association Inc. in response to an increasing awareness of "Centering" and the number of sites providing this model. The Centering Healthcare Institute promotes the "Centering" model of care throughout the lifecycle, and provides education, training, and support for persons and organizations worldwide.

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