Gestational diabetes, hyperemesis gravidarum, preeclampsia, obesity and folate use are frequently studied topics. Some studies showed a lower prevalence of some pregnancy outcomes, but a majority of the studies showed a relatively high risk of disease among immigrant women, including a high prevalence of gestational diabetes. The findings emphasise the need for closer monitoring of immigrant women during pregnancy. Study results have led to changes in professional practice, such as the introduction of screening for gestational diabetes for women of Asian or African ethnicity (49).
An exploratory literature review includes studies regardless of the research study design, and it does not involve a formal quality assessment of the articles selected for inclusion, which distinguishes it from a traditional systematic review article (50). Since the authors did not assess the quality of the articles included in this review, the level of confidence in the results described in those articles cannot be assessed.
Our increased knowledge about the prenatal health of immigrant women can probably be attributed to the fact that a number of studies, such as STORK Groruddalen, specifically include immigrants. In recent years, national registries have also increased the possibility of including variables specific to immigrants (51). In 2010, an international panel recommended the inclusion of a minimum set of variables when conducting research on maternal health among immigrants (52). In descending order, this includes country of birth, length of residence, reason for immigration, language comprehension and ethnicity. In our material, factors other than country of birth and ethnicity were seldom included. Future research should include more migration-related factors that may provide a nuanced and more accurate picture of various risk profiles.
Differences in health outcomes are explained in part by language barriers (11, 53), but we found few studies on the association between language skills, use of interpreters and adverse pregnancy outcomes. We found no quantitative studies that investigated immigrant women's use of prenatal care services or models for prenatal care especially adapted for immigrant women. International literature underscores the need for more knowledge about particularly vulnerable immigrant women, such as new arrivals, refugees and undocumented immigrants (53). We recommend that future studies do more to include these groups. Intervention studies that explore various measures for improving prenatal care have been conducted in Denmark and other European countries (54, 55) and should also be tested in Norway. Furthermore, we recommend conducting more qualitative studies that shed light on the experiences of health professionals and immigrant families.