The tall, thin women of the Uduk and Dinka people of southern Sudan would fall into this category. A more common cause of CPD in the developing world is early marriage. Many different ethnic groups find it quite acceptable for girls to marry and become sexually active even before the age of 10. Pregnancy can occur simultaneously with menarche. Girls who are still years from reaching adult size often simply do not have room in the pelvis for a normal delivery to take place.
Early marriage is a practice deeply rooted in tradition.
This is a very, very difficult, but not impossible, thing to do. It has been shown that poor nutritional status can predispose women to obstructed labor. Areas in the world with highest incidence of childbirth injury are also areas in which famine and malnutrition are common. On an individual level, yes, but changing the cycle of famine and malnutrition in the world's poorest areas takes massive resources. FGM is certainly and rightfully a hot topic in the area of women's rights.