Transient laxity in association with pregnancy of the native anterior cruciate ligament has been previously documented. This phenomenon has only been previously reported in one case of ACL reconstruction, but it has been recommended that patients that become pregnant soon after surgery should be closely observed. We report three cases of pregnancy in relation to primary ACL reconstruction with no obvious adverse outcomes observed on objective assessments. We also report one case of revision ACL reconstruction during pregnancy with a good clinical outcome. We suggest that any hormonal effects on ACL reconstruction during pregnancy, if they do occur, are likely to be very transient and of doubtful clinical impact. In addition, we feel that pregnancy should not be regarded as an orthopaedic contraindication to ACL reconstruction surgery.