Summary of evidence
This study, using population-based data from the Norwegian Birth Registry shows that there is a globally significant effect of birthplace on the use of epidural analgesia. We demonstrated some disparities in the provision of epidural analgesia by maternal birthplace. Immigrants from Latin America/Caribbean were consistently more likely to be provided epidural analgesia compared to native-born women. In contrast, the provision of epidural analgesia in immigrants born in low- and middle-income countries varied across maternal birthplace. Compared to native-born women, women born in Sub-Saharan Africa or East Asia/Pacific were less likely to be provided epidural analgesia. Longer residence time in Norway was associated with a higher likelihood of being provided analgesia, whereas effects of maternal education depended on GBD group.
Our results for Sub-Saharan women in Norway confirms findings from Bakken et al. (2015) of the low provision of epidural analgesia among Somali-born immigrants, the largest migrant group from Sub-Saharan Africa in Norway . Regarding South Asian women, we found that primiparous women had similar chances of being provided epidural analgesia as native-born women, whereas multiparous women had a reduced likelihood. This is in line with a previous Norwegian study by Vangen et al. , where Pakistani-born women were found to be provided less epidural analgesia regardless of parity.
Our results are likely to have multicausal explanations. Firstly, our result could be influenced by real differences in women’s own wishes and needs. Cultural norms and perceptions of labor pain as well as knowledge of side effects of pain relief could affect women’s choices, even though women’s prenatal analgesia preference does not always match their actual use . However, we found significant variation also in women exposed to an instrumental vaginal delivery, where pain relief is strongly advised by the midwife and obstetrician. Overall, primiparous women had a higher likelihood of being provided epidural analgesia compared to multiparous women, and women with instrumental vaginal delivery had a higher likelihood compared to spontaneous delivery. This was expected, as primiparous women have a longer duration of delivery and more interventions by instrumental deliveries. In addition, instrumental vaginal delivery is more painful than spontaneous vaginal deliveries.Secondly, our results can be explained by pre-migration exposure to health system practices and norms in the home country. We found high provision of epidural analgesia among women born in Latin America/Caribbean region. In line with this, the epidural analgesia rate in Chile and in private health facilities in Brazil is higher than in Norway [18, 19]. Conversely, in low- and middle-income countries, access to epidural analgesia is often suboptimal. In our study we found a low provision of epidural analgesia in women born in Sub-Saharan Africa. Outside tertiary facilities in these women’s home countries management of labor pain often only involves non-pharmacological pain relief .
Thirdly, low uptake of pain relief in certain groups could be influenced by suboptimal communication, especially if language barriers were present. A study among Hispanic women in the US found lower provision of epidural analgesia among Hispanic women as compared to whites, and language barriers mediated that difference . Both language barriers and misconceptions about possible pain relief may contribute to a communication barrier between the women and the health care providers . Orejula et al. reported misconceptions about the safety of epidural analgesia in foreign-born women . When language barriers are present, individual support by a laywoman (doula) matched by language and cultural preference of the woman giving birth, has been attempted with the aim of providing translation and advocacy to the woman . A recent Cochrane review supports the use of doula as a resource to foreign-born delivering women in high-income countries .
Finally, health literacy and level of education could also have impacted our findings. Women in minority groups have previously reported poorer experience of maternity services . We cannot exclude that lower provision of epidural may be determined by a paternalistic attitude among the healthcare staff towards women of lower socioeducational groups. Higher educated women born in Sub-Saharan Africa, North Africa/Middle East or South Asia were more likely to be provided epidural analgesia, compared to those with lower education from the same areas. Furthermore, we found increased provision of epidural analgesia with longer residence in Norway, implying a potential acculturation effect . In our study, Pakistani born women constituted 72% of the South Asian group, which also was the group of women that had the longest residence time in Norway in our study. Longer residence time is associated with improved health literacy, including improved language proficiency, which could strengthen the participation in decision-making. Good language skills could modify a negative impact of ethnicity on the provision of analgesia during delivery . At the same time, increasing familiarity with and knowledge of cultural-specific attitudes might improve the effort and communication skills among health staff themselves.
We also examined pain relief in emergency cesarean deliveries. In Norway, 21% of all cesarean deliveries are due to failure to progress , and in these women epidural analgesia is especially useful. However, as we lacked data on indication for emergency cesarean delivery, these results are difficult to interpret.
Strengths and limitations
Strengths of this study include the use of a large, nation-wide birth cohort with minimal selection bias, including more than 175,000 births among immigrant women. The completeness of the MBRN is close to 100% and misclassifications are believed to be minimal [14, 15]. The linkage with national statistics enabled us to include information on maternal education level and residence time in Norway, as proxy indicators of health literacy and acculturation, respectively. The use of the GBD framework to classify the immigrant population may also be evaluated as strength, as the framework combines geographical and economical aspects of the country of birth.
The study has some limitations. The categorization of different countries into GBD groups may cause a loss of detailed information from particular countries. In addition, we assume that women originating from a particular geographical region share common traits, disregarding the heterogeneity in sociocultural background, religion, attitudes and a selection to migration. We controlled for predefined potential confounders; however, we did not have information on language skills, interpreter use or health literacy. The relative risk of epidural analgesia was based on logistic regression analyses adjusted for potential confounders, assuming additive effects. When investigating the presence of effect modification, using a strict significance level, we found a clear and consistent interaction between the provision of epidural analgesia and education. However, due to the large sample size, we cannot exclude spurious interaction effects and results should be interpreted with caution. In addition, there has been an increased provision of epidural over the study time period. To take into any consideration time-dependent effects, we included year of birth in the regression analysis. Thus, we believe that any bias from time-dependent effects have been adjusted for in the final models.
Other types of pain relief (nitrous oxide, intravenous opiates etc) were outside the scope of this study, however we performed sub analyses for spinal analgesia and pudendal block (Supplementary Table 4 and 5).
Due to the heterogeneity of the immigrant populations, our results cannot necessarily be generalized to other settings. However, in countries with a similar immigration pattern and universal free maternity care, results may be similar. To determine why there are disparities in the provision of epidural analgesia, future studies exploring women’s own perspectives are needed.