Preterm birth and low birth weight are the leading causes of infant morbidity and mortality, are associated with an increased risk of poor health and economic outcomes throughout the life course and are an important indicator of overall population health. In the US, disparities in these outcomes exist across both race/ethnicity and nativity status, whereby US- and foreign-born Latina women are more likely to experience preterm birth and low birth weight than US-born white women. Latina women are also less likely than their white counterparts to utilize prenatal care, an important determinant of adverse birth outcomes. These disparities persist even after controlling for socioeconomic indicators, health behaviors, and medical risk factors, pointing to sociopolitical factors, like state-level policy, as potential causes.States have increasingly set their own immigrant policy agenda, passing restrictive policies denying immigrants' rights and access to health-promoting resources. Omnibus immigrant laws are considered the harshest state-level immigrant policies to ever pass in the United States (US). These laws were passed with the explicit intent to drive immigrants to "self-deport" by severely regulating their daily life across multiple domains within a single bill. It is suggested that restrictive immigrant policies like omnibus laws had deleterious effects on pregnancy outcomes among Latina women, regardless of their nativity status, due to widespread stress and fear, increased experiences of racial profiling and discrimination, and decreased access to beneficial social institutions and material conditions following their passage. However, to date, no studies have considered the totality of omnibus immigrant laws enacted across the US states and their potential effects on pregnancy outcomes among Latina women. Moreover, questions remain related to the extent that US-born Latinas would be affected by omnibus immigrant laws, especially given that these laws do not explicitly target US-born individuals as written. Finally, it has been posited that differences in the effects of restrictive immigrant laws may also exist across national origin subgroups; however, to date, no studies have formally evaluated potential differences in the health effects of restrictive immigrant laws across national origin subgroups of Latinos. This dissertation utilized national natality data from 2005 to 2014, encompassing the period during which omnibus immigrant legislation was passed across the US states, and a quasi-experimental interrupted time series design to: 1) determine the effects of omnibus immigrant laws on preterm birth, low birth weight, late entry into prenatal care, and inadequate prenatal care utilization, respectively, among Latina women in the US; 2) understand differences in these effects across nativity status, comparing outcomes among foreign-born versus US-born Latina women; and 3) determine if differences in the effects of omnibus immigrant laws on pregnancy outcomes exist across the largest national origin subgroups of Latinos in the US, comparing outcomes among women of Mexican, Puerto Rican, and Cuban origin or descent. I found substantial evidence that the passage of omnibus immigrant laws caused a significant increase in the odds of preterm birth among Latina women, largely driven by effects among infants born to foreign-born Latinas generally and Mexican-born Latinas specifically. I also found evidence that the passage of omnibus immigrant laws resulted in an increased odds of preterm birth among all Latinas of Mexican origin or descent, regardless of nativity status. I also find some evidence that the passage of omnibus immigrant law resulted in an increased odds of low birth weight among infants born to foreign-born women from Mexico and Latina women of Mexican and Puerto Rican origin or descent, respectively, but a decreased odds of low birth weight among women of Cuban origin or descent. Moreover, although omnibus immigrant laws had either no effect on late entry into prenatal care or resulted in an improvement in the timing of prenatal care initiation for some groups, I found that their passage led to an increase in the odds of inadequate prenatal care utilization among foreign- and US-born Latinas, foreign-born Latinas from Mexico, and women of Puerto Rican and Cuban origin or descent, respectively. This suggests that the passage of omnibus immigrant laws may be more likely to impact women's ability to attend all the recommended number of prenatal care visits throughout pregnancy rather than the timing of prenatal care initiation. Notably, unlike my findings related to preterm birth which were extremely robust to sensitivity analyses, findings related to the effects of omnibus immigrant laws on low birth weight and prenatal care indicators were more likely to be sensitive to the inclusion of specific states (or policies) in the analytic model. This suggests that the extent that omnibus immigrant laws influence these outcomes may depend more on the specific provisions (or mix of provisions) included within each omnibus immigrant law and other factors of the local and state context. Finally, although I found limited evidence that the passage of omnibus immigrant laws resulted in significant spillover effects when assessing outcomes among US-born Latinas generally, my finding that their passage resulted in poorer pregnancy outcomes among those of Puerto Rican origin or descent provides evidence that these laws may still result in negative health outcomes even among those individuals not directly targeted by the laws as written (as all Puerto Ricans would have US citizenship regardless of whether or not they are born on the island or within the 50 US states). This dissertation adds to a growing body of literature that investigates the effects of restrictive state-level immigrant policies on health outcomes among Latinos and is the first to demonstrate variability in the effects of such policies across the three largest national origin subgroups of Latinos in the US, highlighting the importance of disaggregating data in analyses to better account for the vast heterogeneity that exists among this group. These findings also have important implications for programming and policy. These findings can be used to develop interventions aimed at improving maternal and child health outcomes that are targeted toward specific communities (e.g., foreign-born Latinas or those of Mexican origin or descent) who may be particularly vulnerable to the negative consequences of restrictive immigrant policies. Additionally, although an omnibus immigrant law has not been passed in nearly a decade, immigration remains a highly salient topic in US politics and restrictive immigrant policies continue to be a central feature of the state legislative agenda. Thus, these findings not only illuminate the impacts of omnibus immigrant laws specifically, but also shed light on the potential negative effects of other state-level, single-issue restrictive immigrant policies commonly passed throughout the US each year. In turn, this dissertation research may be used to inform contemporary immigrant policy reform, debate, and advocacy work directed at both the federal and sub-federal levels.