The effect of the full lateral position on aorto-caval compression

The sources of variation in the duration of the second stage of labour and their relative contribution to the total variability on the basis of multiple linear stepwise regression in 964 parturients (Nullipara 473, Multipara 491). Total R2 = 0.233.
Reproduced with permission from Piper et al Am J Obstet Gynecol 1991; 165:976-979.