I recently heard a claim that Asians in general have more difficult births than Europeans. Is this true?
I have found a few studies(1,2) on the effect of ethnicity on birth outcomes but they seem to be limited to a small geographic area or focus on aspects such as risk of premature birth, neonatal and/or maternal mortality, etc. Those are of course important facts, but I am more interested in whether an otherwise normal birth is likely to be longer and/or be perceived as more difficult by this specific ethnic group, on basis of their ethnicity alone.
I found a few articles dealing with possible effects of specific genes on duration of labor. Debiec et al. (3) write that
Asian women had slower active labor than other ethnicities (P < 0.01). Asian women also reported less pain during their labor compared to all other patients (P < 0.001). Slower labor progress was associated with less rapid progression of pain, but this did not obviate the effect of Asian ethnicity on pain.
According to Reitman et al.(4,5) the genotype CC at the SNP Rs1042714(9), which is more prevalent in ethnic Asians, is associated with longer duration of first-stage labor. Polymorphisms in the oxytocin receptor (OXTR) gene have also been tied to variations in labor progress (6,8), but I haven't found data on the prevalence of these polymorphisms in Asian populations.
Greenberg et al. (7) write that "Nulliparous Asian women had a significantly longer second stage and higher rates of prolonged second stage". However, after controlling for confounding variables the actual increase in mean second-stage duration compared to white women was only 5.2 and 5.9 minutes for nulliparous Asian women with and without epidural analgesia, respectively. They also write that
When the rates of second stage of >3 hours were analyzed by epidural subgroups in the multivariate analysis, black women with epidural analgesia had lower rates than white women, and Asian women with epidural analgesia had higher rates than white women, regardless of parity, although no differences were demonstrated among women without epidural analgesia.
Considering the above sources and any other that may exist, is it reasonable to state that Asian women in general have more difficult births than white/European women?