Abstract
The “healthy immigrant effect” or “healthy migrant effect” refers to the generally accepted occurrence of more favorable health outcomes among new immigrants to developed countries relative to comparable native-born populations. 1 This advantage is present despite the majority of immigrants coming from developing countries where morbidity and mortality indicators are generally higher than in the developed countries to which they are migrating. Several potential explanations for this phenomenon have been described in the literature, including (1) health screening or selection of immigrants with specific skills by immigration officials of the host country, (2) healthier lifestyle behaviors of new immigrants, (3) immigrant self-selection whereby the fittest or wealthiest are most likely to migrate, and (4) less healthy immigrants returning home due to illness. 1
Consistent with this phenomenon, several studies have observed that immigrant women tend to have more favorable birth outcomes than U.S.-born women, including lower rates of preterm birth and low birth weight. 2 However, many of these studies used broad racial/ethnic categories or lumped all “foreign-born” women together, not accounting for differences in immigration status and experience. 3 In addition, very few studies have specifically looked at birth outcomes of refugees (a particular subset of immigrants) who have been resettled in the United States.
In this issue, Agbemenu et al. examine prepregnancy health status, prenatal behaviors, and reproductive health outcomes among African refugee women, compared with U.S.-born black and white women in Erie County, NY. 4 Based on electronic birth certificate data, 77,891 women gave birth during 2007–2016: African women accounted for 1% (n = 789), U.S.-born black women accounted for 22.5% (n = 17,487), and U.S.-born white women accounted for 76.5% (n = 59,615) of the births during this period. The refugee women were from Somalia (68.3%), Democratic Republic of the Congo (9.8%), Eritrea (8.9%), Rwanda (7.7%), and Burundi (5%).
Although the authors of the study hypothesized that the refugee women would have poorer reproductive health outcomes than the U.S.-born comparison groups “due to lower socioeconomic status, poor health care utilization, and maternal risk factors related to the refugee process,” the opposite was found. The African women had the fewest number of preterm births and low birth weight infants. The disparity was greatest between the African and U.S.-born black mothers, with the latter group having over twice the incidence of preterm and low birth weight infants compared with the refugee women.
What can explain these unexpected findings? Despite having fewer prenatal visits and initiating care later in pregnancy, the refugee women were generally healthier than the U.S.-born women, that is, they had fewer prepregnancy medical risk factors (hypertension, diabetes, or other serious chronic conditions). In addition, refugee women smoked significantly less (0.5%) and were less likely to use drugs (0.6%) during pregnancy than the U.S.-born black (15.3% and 18.6%, respectively) and white women (12.2% and 4.5%, respectively). Interestingly, a larger proportion of the refugee women had lower income as reflected in a higher proportion of Medicaid, and had less education. However, more refugee women were married (76.0%) compared with U.S.-born black (13.1%) and white (67%) women.
These results support the healthy immigrant effect operating to produce these favorable birth outcomes. Of the potential explanations for the healthy immigrant effect described previously, the most likely one is the better health status and behaviors of the refugees, that is, fewer chronic illnesses and lower rates of smoking and drug use. Refugees, unlike most immigrants, do not have the opportunity to choose to emigrate—civil wars in each of the African countries from which this sample of women originated forced these women and their families to flee in a hurry. However, they may have been more resilient and resourceful than others to have made it through the long process of dislocation and resettlement. Having come with their families and having their support, especially their husbands, also likely contributed to their better birth outcomes.
U.S.-born blacks have had persistently higher rates of preterm birth than non-Hispanic white and Hispanic women for decades, and this disparity is complicated by the complexity of the multiple risk factors for this condition, including those with biological, social, and psychological bases. 5 The strongest evidence to explain the racial-ethnic disparity in preterm birth points to infection and inflammation, estimated to contribute a sizable component of the gap. Is it possible that the refugee women have fewer infections or inflammatory conditions of the urogenital tract or endometrium? Other research points to racism and chronic stress contributing actively to the disparity in these birth outcomes among U.S.-born black women. 5 It has been proposed that external stressors, including material hardship, low social support, and individual factors such as lower self-efficacy, sense of control, and resilience, also contribute. 5 Although the refugee women face material hardship, numerous challenges in the United States, and the stresses of war and dislocation, it appears that their healthier behaviors, resilience, and social support are the most important factors in leading to better outcomes.
Agbemenu et al. propose four recommendations, which I endorse, to ensure that African refugee women continue to have optimal reproductive outcomes: (1) continue to conduct research to gain a more nuanced understanding of refugee women's experiences with reproductive health care; (2) develop and provide culturally congruent reproductive health education, including prenatal care and family planning; (3) provide trauma-informed pregnancy care to refugee women that acknowledges the common history of trauma in their lives; and (4) continue to monitor the health status of women in the African refugee community to determine if the healthy immigrant effect persists in the face of acculturation to the host country and to nurture those practices that contribute to positive health outcomes. 4 They also recommend extending these interventions to other groups at high risk of poor birth outcomes. In addition, I would suggest including the role of fathers in future research. In a study by Krishnakumar et al., foreign-born fathers (European and African ancestry) were found to have 15% fewer low birth weight infants than U.S.-born fathers after controlling for race and birthplace of the mother. 6
In conclusion, further research is very much needed that follows refugee women throughout their reproductive lives, including childbirth, to ensure that the birth advantages shown in this study are replicated. Ideally, more information about refugee women would be obtained, including paternal factors and years since resettlement in the United States, during which time the more detrimental aspects of acculturation to American lifestyles may affect birth outcomes. Studying these outcomes among refugee women can provide clues to better understand the causes of racial-ethnic disparities, with the goal of providing culturally appropriate interventions to all at-risk groups.