title: Randomised clinical trial to assess anal sphincter function following forceps or vacuum assisted vaginal delivery.
abstract: OBJECTIVE
  To compare, in a prospective, randomised controlled trial, differences in anal sphincter function following forceps or vacuum assisted vaginal delivery in an institution practising standardised management of labour.
  
  
  METHODS
  Prospective, randomised controlled trial.
  
  
  METHODS
  Tertiary-referral maternity teaching hospital.
  
  
  METHODS
  One hundred and thirty women.
  
  
  METHODS
  Primiparous women were recruited antenatally and if an instrumental delivery was indicated, were randomised to either a vacuum or low-cavity, non-rotational forceps assisted delivery. Follow up consisted of a symptom questionnaire, anal manometry and endoanal ultrasound at three months postpartum.
  
  
  METHODS
  Faecal continence scores, anal manometry, endoanal ultrasound.
  
  
  RESULTS
  Sixty-one women delivered with forceps assistance (40 for failure to progress in the second stage) and 69 with vacuum assistance (33 for failure to progress); 16/69 vacuum deliveries proceeded to a forceps assisted delivery (23%). There were no statistical differences in the antecedent antenatal factors between the two groups. A third degree perineal tear followed 10 (16%) forceps and 5 (7%) vacuum deliveries. Based on intention-to-treat analysis, 36 (59%) women complained of altered faecal continence after forceps delivery compared with 23 (33%) following vacuum delivery three months postpartum (RR 2.88, 95% CI 1.41-5.88). Endoanal ultrasound was reported as abnormal following 34 (56%) forceps deliveries and 34 (49%) vacuum deliveries (RR 1.3, 95% CI 0.65-258). After exclusion of 'failed vacuum', median anal canal resting pressure was significantly lower following forceps delivery compared with vacuum delivery alone (P = 0.004). There were no significant differences in degree of ultrasound abnormality between the two groups.
  
  
  CONCLUSIONS
  Symptoms of altered faecal continence are significantly more common following forceps assisted vaginal delivery. Based on continence outcome, when circumstances allow, vacuum should be the instrument of first choice in assisted delivery.
authors.affiliation: Department of Obstetrics and Gynaecology, National Maternity and Mater Misericordiae Hospitals, University College Dublin, Ireland.
authors.forename: Myra
authors.initials: M
authors.lastname: Fitzpatrick
authors.forename: Michael
authors.initials: M
authors.lastname: Behan
authors.forename: P Ronan
authors.initials: PR
authors.lastname: O'Connell
authors.forename: Colm
authors.initials: C
authors.lastname: O'Herlihy
mesh_terms: D000328:Adult; D001004:Anus Diseases / Q000000981:diagnostic imaging / Q000209:etiology* / Q000503:physiopathology; D004841:Episiotomy / Q000009:adverse effects; D005242:Fecal Incontinence / Q000000981:diagnostic imaging / Q000209:etiology* / Q000503:physiopathology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007744:Obstetric Labor Complications / Q000628:therapy; D011247:Pregnancy; D011312:Pressure; D011446:Prospective Studies; D011644:Puerperal Disorders / Q000000981:diagnostic imaging / Q000209:etiology* / Q000503:physiopathology; D014463:Ultrasonography; D014620:Vacuum Extraction, Obstetrical / Q000009:adverse effects*