 Bigrigg et al in 1994 performed a case controlled questionnaire regarding the safety and efficacy of LLETZ and this involved questions regarding infertility. There were 250 matched pairs- women who had had a LLETZ study group and those women identified who had normal cytology from their database control group, for the entire study, but only 134 women answered the questions on infertility 72 in the LLETZ group and 62 in the control group. The investigators reported no apparent difference in infertility between the groups. Again this study was limited by size -72 in the study group and 62 in the control group could remember how long it took to conceive. 