Latinas in the U.S., especially immigrant women, have infants whose birth weight is as healthy as that of more affluent European American women (Callister & Birkhead, 2002; Campos et al., 2008; Montoya-Williams et al., 2020; Zambrana et al., 1997). This surprising pattern is an important example of the “Latino Health Paradox” whereby Latinos in the U.S. have historically had better than expected health despite their socioeconomic disadvantages and devalued ethnic minority status (Abraido-Lanza, Dohrenwend, Ng-Mak, & Turner, 1999; Markides & Coreil, 1986; Ruiz, Steffen, & Smith, 2013). Unfortunately, these initially favorable perinatal outcomes worsen with more time and acculturation in the U.S. (Callister & Birkhead, 2002; Campos, Schetter, Walsh, & Schenker, 2007; Zambrana et al., 1997).

Acculturative changes, including those characterized by a transition from Latino to U.S. orientation, likely involve biopsychosocial mechanisms relevant to pregnancy outcomes, such as stress. In large-scale prospective studies stress has been predictive of adverse pregnancy outcomes, including lower fetal growth (Dunkel Schetter, 2009, 2011). With more time in the U.S. and higher levels of U.S. acculturation, Latinas report higher levels of stress (Kasirye et al., 2005; Zambrana et al., 1997) and experience greater physiological dysfunction (Cedillo et al., 2021). This suggests that U.S. acculturation may be linked to Latinas’ susceptibility to the adverse effects of stress and dysfunction in stress-related physiological systems, such as the cardiovascular system (Marwaha, 2022).

One potential mediator of the link between acculturation and fetal growth is cardiovascular functioning. The hemodynamics involved in the circulation of maternal oxygen and nutrients to the uterus is critical for fetal growth. Changes in BP throughout pregnancy reflect this important dynamic. During pregnancy BP gradually decreases in the first 22 to 24 weeks gestation and then gradually increases until parturition (Grindheim, Estensen, Langesaeter, Rosseland, & Toska, 2012; Pivarnik, Szymanski, & Conway, 2016). These adjustments are, in part, the result of an increase in blood volume necessary to sustain the growing fetus. Although a mid to late term increase in BP is normative, high BP can also indicate risk of complications.

During pregnancy, BP that is clinically high at its peak (systolic BP≥140mmHg) or at its nadir (diastolic BP≥90mmHg) increases risk of pre-eclampsia, a risk factor for lower fetal growth (Preeclampsia and Eclampsia, 2013). At sub-clinical levels and in the context of high stress, our research suggests that diastolic BP (DBP) is a stronger predictor of fetal growth than systolic (SBP) (Hilmert et al., 2014; Hilmert et al., 2008). Therefore, in the present study we consider SBP and DBP, separately.

Associations between BP during pregnancy and pregnancy-related outcomes are well documented. However, the pathways by which acculturation influences BP-related processes during pregnancy are not. In the current study we examine the complex dynamics of cultural orientation, stress, BP during pregnancy, and fetal growth in a sample of 1,011 Latinas.

This study is the first to link cardiovascular functioning to U.S. acculturation as a mechanism impacting Latina pregnancy outcomes. Acculturation has been associated with increased cardiovascular disease in Latino populations (Daviglus et al., 2012) potentially due, in part, to acculturation-related stress (Kasirye et al., 2005; Zambrana et al., 1997) and the impact of stress on the cardiovascular system (Marwaha, 2022). The present results provide important new evidence that Latinas who had higher levels of U.S orientation also had DBP trajectories during pregnancy associated with less favorable birth outcomes.

In the present study, stress and family support measures were not significantly associated with U.S. orientation, BP, and pregnancy outcomes. Past research has shown that the perceptions and effects of psychosocial variables change over the course of pregnancy (Glynn, Schetter, Wadhwa, & Sandman, 2004; Glynn, Wadhwa, Dunkel-Schetter, Chicz-Demet, & Sandman, 2001) but psychosocial measures were only assessed at a single timepoint in SHARE. Nuanced changes in stress and family support that could be related to U.S. acculturation may have been missed. Future research needs to consider a more sophisticated interplay of social experience, cardiovascular functioning, and pregnancy outcomes.

It is also possible that U.S. acculturation has effects on cardiovascular functioning relevant to pregnancy that are independent of the psychosocial processes assessed in the present study. That is, the long term process of U.S. acculturation (Padilla & Perez, 2003; Schwartz et al., 2010), which involves the difficulties of adapting to a devalued ethnic minority status for Latinas, may have affected the functioning of the cardiovascular system, perhaps through repeated stress responses or allostatic load (McEwen, 2004). Such impact may not be evident in associations between current cardiovascular functioning and proximal psychosocial stress. Consistent with this, past research has found that a lifetime of discrimination stresses experienced by African Americans affects cardiovascular functioning (Gee, Walsemann, & Brondolo, 2012; Geronimus, 1992, 1996) and that childhood experiences of racism, but not adulthood experiences, interact with BP to predict pregnancy outcomes (Hilmert et al., 2014). To best understand the impact of U.S. acculturation on physiology, researchers should consider related stress experiences over the life course.

A possible limitation of this study is the sample’s restricted variance on the U.S. orientation measure. Three quarters of the sample (74.6%) were FB and reported low levels of U.S. orientation (Table 1). In a sample with a wider range of U.S. acculturation experiences future research can consider whether adoption of a new culture and loss of one’s original culture are differentially associated with pregnancy outcomes. Also, this sample lacked variability in SES (see Kasirye et al., 2005), which was not included in the present model. Despite these potential limitations, we were able to leverage continuous measures of acculturation, BP, and pregnancy outcomes to detect theoretically consistent and meaningful patterns. Future studies that focus on the many ways in which U.S. acculturation unfolds and intersects with Latino experience in ways that may impact blood pressure can build on the findings of this work. Furthermore, future research should consider how other acculturation-related changes in physiology, including immune and endocrine parameters (Scholaske, Wadhwa, & Entringer, 2021) may be contributing to the association between DBP and fetal growth.

Acculturation to the U.S. is known to be a significant risk factor for cardiovascular health, and now this work connects Latina pregnancy to this pattern. In the future, awareness of a woman’s acculturation and DBP changes during pregnancy may help to better identify those at risk of having lower birth weight babies. It is also possible that targeting the cardiovascular functioning of more acculturated Latinas during pregnancy via BP-related interventions such as relaxation techniques or medication could help mitigate rates of low birth weight deliveries. Future studies may also want to consider whether aspects of Latino culture that may provide health advantages (Campos, Yim, & Busse, 2018) can be recovered and benefit U.S. acculturated Latina pregnancies. Altogether, this research suggest that cardiovascular functioning is a promising new avenue for understanding the role of the socio-cultural environment in pregnancy health generally and in ethnic-minority experience specifically. We hope researchers are inspired by these findings to pursue future research on this topic; it is needed to arrive at a comprehensive understanding of the biopsychosocial nature of health.