Assessment of the variability in the dimensions of the intact pelvic canal in South Africans: A pilot study

Abstract

Cephalopelvic disproportion is common among Africans and is a major cause of maternal and perinatal mortality and morbidity. As the dimensions of the pelvis may vary between populations and according to stature and age, they need to be considered during childbirth and also in the planning and performance of pelvic and perineal procedures. The aim of this study was to assess the possible variations in the dimensions of the intact pelvic canal in South Africans and their implications. Eighty intact cadaver pelves, belonging to 40 white South Africans (20 males and 20 females) and 40 black South Africans (20 males and 20 females) were used for both metric and geometric morphometric analyses. Pelvic inlet shapes did not differ significantly between groups but pelvic inlet and midpelvic dimensions were the greatest in whites and females. The pubic symphyseal length was the greatest in whites and males and the smallest in black females, resulting in a smaller pelvic cavity anteriorly than for white females. Pelvic outlet shapes varied significantly between sexes in white South Africans and between populations in males. Females presented with the greatest dimensions. Black females presented with an elongated anteroposterior outlet diameter. Certain transverse pelvic diameters correlated positively with age in white males and with height in females. In planning childbirth options, the smaller pelvic inlet of black females and stature-dependent diameters should be considered. Pelvic and perineal 1 surgery may be technically more challenging because of smaller pelvic dimensions in black South Africans, especially in males.

Obstetric dimensions of the female pelvis are less integrated than locomotor dimensions and show protective scaling patterns: Implications for the obstetrical dilemma

“…Studies that have examined pelvic variation with height in humans and nonhuman primates have presented diverse results in the pelvis. Some studies suggest that pelvic dimensions do not correlate with height (Kurki, 2011a, 2013; Takamuku, 2019; Wood & Chamberlain, 1986), while others found correlations in certain dimensions (Jagesur, Wiid, Pretorius, Bosman, & Oettlé, 2017; Lewton, 2015; Mobb & Wood, 1977; Sharma, Gupta, & Shandilya, 2016; Tague, 2000). Certain pubic measurements did show correlation (Jagesur et al, 2017) and allometric scaling with height (Mobb & Wood, 1977).…”

“…Some studies suggest that pelvic dimensions do not correlate with height (Kurki, 2011a, 2013; Takamuku, 2019; Wood & Chamberlain, 1986), while others found correlations in certain dimensions (Jagesur, Wiid, Pretorius, Bosman, & Oettlé, 2017; Lewton, 2015; Mobb & Wood, 1977; Sharma, Gupta, & Shandilya, 2016; Tague, 2000). Certain pubic measurements did show correlation (Jagesur et al, 2017) and allometric scaling with height (Mobb & Wood, 1977). Similarly diverse results have been presented regarding the relationship between pelvic obstetric dimensions and weight, with some dimensions showing independence from weight (Tague, 2000), and others, including birth canal size, correlating with weight (Kurki, 2011a; Tague, 2000), body width (Kurki, 2013; Tague, 2000), or body size (Kurki, 2007; Sharma et al, 2016).…”