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2. Births in Scotland Report 2002 (Births 1981–2000) Information and Statistics.Division. www.show.scot.nhs.uk/isd/sexual_health.
3. Birthchoice UK Maternity Statistics (2000–2009). www.birthchoiceuk.com.
4. The obstetric vacuum extractor is the instrument of first choice for operative vaginal delivery;Chalmers;BJOG,1996
5. Vacuum extraction versus forceps for assisted vaginal delivery;Johanson;Cochrane Database Syst Rev,2000