BACKGROUND When pregnant women near term lie in the supine position the uterus can compress the inferior vena cava, interfering with venous return to the heart. This can result in hypotension, reduced placental perfusion and decreased fetal oxygenation. OBJECTIVE The objective of this review was to assess the effects on the fetus or newborn of lateral tilt at caesarean section compared to the operation carried out with the mother in the supine position. METHODS We searched the Cochrane Pregnancy and Childbirth Group trials register. METHODS Randomised or quasi-randomised trials of lateral tilt (10 to 15 degrees) compared to supine position during caesarean section in pregnant women undergoing elective or emergency caesarean section. METHODS Trial quality assessment and data extraction were done by one reviewer. RESULTS Three trials involving 293 women were included. The trials were all methodologically poor. There were fewer low Apgar scores when lateral tilt was used, and pH measurements and oxygen saturation appeared to be better when tilt was used. CONCLUSIONS There is not enough evidence from these trials to evaluate use of lateral tilt during caesarean section.