Thorp, John M., Jr. (1994). A Randomised Prospective Study Comparing the New Vacuum Extractor Policy with Forceps Delivery. BJOG: An International Journal of Obstetrics & Gynaecology, 101(4)
I am concerned that in the study by Johanson et al. (June 100, 1993) the authors failed to control for the confounding variable of episiotomy. Two studies in the United States have clearly demonstrated that midline episiotomy increases the risk of rectal injury in operative vaginal deliveries (Combs et al. 1990; Helwig et al. 1993). We cannot accept the study conclusion that the new vacuum extractor policy is associated with less maternal trauma until provided with information about episiotomy rates and techniques in the two groups.
BJOG: An International Journal of Obstetrics & Gynaecology
Thorp, John M., Jr.