Pacific Islanders bear a disproportionate burden of obesity compared to other racial/ethnic minorities and the United States (US) population. Pacific Islanders residing in the US also have high maternal and infant health disparities with disproportionally high rates of preterm birth (<37 weeks) and low birthweight infants (<2,500 grams). They are also more likely to experience preeclampsia, primary cesarean birth, excessive gestational weight gain, gestational diabetes mellitus, and low exclusive breastfeeding rates compared to other racial/ethnic minorities and the US population in general. These unique health circumstances increase medical complications and are associated with impaired glucose intolerance, delivery complications, and higher incidence of obesity and metabolic disease risk later in life for infants. Early and consistent supportive care throughout the pregnancy continuum is strongly associated with positive birth outcomes that can mitigate childhood obesity.

However, Pacific Islanders are less likely to receive adequate prenatal care compared to other racial and/or ethnic minorities. Our preliminary studies using Arkansas birth records (n=2,488; 2019) have shown that Marshallese experience exceptionally poor perinatal outcomes, even compared to other US Pacific Islanders. Specifically, 15% of Marshallese women received no prenatal care (compared to 1.6% women nationally); more than 50% do not attend the recommended number of prenatal care visits; 19% of Marshallese infants were born preterm (compared to 9.6% nationally); and 15% of Marshallese infants were low birthweight (compared to 8.3% nationally). These poor health outcomes are highly associated with childhood obesity risk through increased odds of rapid infant weight gain and sub-optimal infant feeding practices. Thus, our foundational work demonstrates an urgent need for culturally adapted interventions to engage the Marshallese community in Arkansas in prenatal care that optimize birth outcomes that can mitigate childhood obesity.

CenteringPregnancy, an evidenced-based group prenatal care model, challenges the standard model of one- on-one prenatal counseling and has demonstrated effectiveness in other populations in lowering the risk of preterm birth, low birthweight infants, and increasing exclusive breastfeeding initiation compared to women receiving individualized care. Our prior work has demonstrated how challenging delivering group care is to the Marshallese community because of transportation barriers. Mobile health clinics are transforming the US healthcare system by delivering services directly to communities of need. However, mobile health clinics have not yet been implemented with group prenatal programs like CenteringPregnancy in the US. The proposed study will determine the preliminary effectiveness of an innovative Mobile CenteringPregnancy program for Marshallese women while also evaluating implementation determinants and outcomes to inform sustainable scaling of the program.

Overview. Using a Hybrid Type 1 effectiveness-implementation trial; the proposed study will establish approaches to determine the preliminary effectiveness of an innovative, culturally adapted, Mobile CenteringPregnancy program to improve prenatal care attendance and the early-stage impact on improved knowledge, attitudes, and behaviors. Additionally, the investigators will establish approaches to determine the effectiveness of Mobile CenteringPregnnacy to improve preterm birth (primary outcome) and maternal outcomes (secondary outcomes): low-birth weight and breastfeeding initiation for Marshallese women. Investigators will also assess implementation outcomes and identify key implementation determinants, which will inform the design of strategies to support wider implementation of the program. A Hybrid Type 1 is the correct study design because the investigators do not yet have robust data on the effectiveness of delivery Mobile CenteringPregnancy to Marshallese women, and both implementation outcomes and determinants are unknown. Our chosen approach also balances scientific rigor and community needs. Investigators will use an external control approach with a propensity score matched comparison group. Investigators considered a two-arm randomized controlled trial, but our community advisors did not feel it was ethical given the stark needs.

In Aim 1, investigators will use a mixed-methods approach to examine adherence to prenatal care appointments and the early-stage impact on knowledge, attitudes, and behaviors at pre-intervention and post-intervention. In Aim 2, investigators will establish key statistical approaches to determine the effectiveness of Mobile CenteringPregnancy to improve preterm birth (primary outcome) and maternal health outcomes (secondary outcome) that promote healthy development and mitigate childhood obesity in infants. A birth certificate data review will be used to document preterm birth, low-birth weight infants, and breastfeeding initiation in the intervention arm and the matched control group. In Aim 3, investigators will assess implementation outcomes and multilevel determinants of implementation and sustainability of Mobile CenteringPregnancy. Using a mixed methods design, investigators will assess implementation of the intervention using the Reach, Effectiveness, Adoption, Implementation, and Maintenance (RE-AIM) evaluation framework. This study will demonstrate the preliminary effectiveness of a culturally adapted Mobile CenteringPregnancy intervention. Further, these aims are in direct response to reviewer comments from a scored NIH RO1 on Mobile CenteringPregnnacy. The data collected from this proposed study will provide the necessary preliminary results to design a larger trail.

Inclusion Criteria:

• (1) women who self-report as Marshallese
• (2) 18 years of age or older
• (3) pregnant (12-14 weeks gestation; confirmed with ultrasound).

Exclusion Criteria:

• (1) conception with the use of fertility treatments
• (2) high-risk pregnancy that requires a transfer to a high-risk clinic
• (3) multiple gestations (i.e. pregnant with more than one infant)
• (4) use of medications known to influence fetal growth (e.g., glucocorticoids, insulin, thyroid, hormones).

All data will be aggregated when disseminated to provide confidentiality to all participants.