Table 1

Included studies on the ‘Finnish intervention’

StudyStudy designData providersPopulationComparator groupsInclusion and exclusion criteriaPrimary outcomeSecondary outcomes
Pirhonen et al 19985Register studySkåne University Hospital, Malmö, Sweden, and Turku University Hospital, Finland30 933 births1990–1994UnknownOASIS: Significantly lower frequency of OASIS in Finland (0.36%) compared to Sweden (2.69%) (p<0.001)Apgar score after 5 min: Lower Apgar score in Finland compared to Sweden (p<0.01), caused by differences in the use of instrumental delivery
Length of second stage of labour: Prolonged second stage in Finland compared to Sweden (p<0.05)
Episiotomy: Significantly more usage of episiotomy in Finland (37.2%) compared to Sweden (24.3%) (p<0.001)
Laine et al 200828Before-and-after studyOestfold Trust Hospital, Norway12 369 births2002–2007All births in one obstetric unitOASIS: Significantly lower frequency of OASIS after implementation from 4.03% to 1.17% (p<0.001)OASIS at instrumental deliveries: Significantly lower OASIS frequency after implementation from 16.26% to 4.90% (p<0.001)
Episiotomy: Significantly more use of episiotomy after implementation from 13.9% to 21.1% (p<0.001)
Laine et al 20096Register studyFinland: Hospital Discharge Register 1987–2007 and Medical Birth Register 2004–2007
Norway: Medical Birth Register, National Public Health Institute
Sweden: Medical Birth Register, National Board of Health and Welfare
Denmark: Medical Birth Register, National Board of Health
1968–2007All vaginal births in Norway (1968–2007)
Sweden (1973–2007)
Denmark (1997–2007
Finland (1987–2007)
OASIS: The frequency of OASIS is significantly higher in Denmark (3.6%), Norway (4.1%), and Sweden (4.2%) compared to Finland (0.6%) (p<0.001)
The frequency is increasing in all four countries
Episiotomy: Significantly decreasing frequency of episiotomy in all countries (no p value reported)
Hals et al 201014Before-and-after studyTromsø University Hospital, Stavanger University Hospital, Lillehammer Hospital, and Ålesund Hospital, Norway40 152 births2003–2009All vaginal births in 4 obstetric unitsOASIS: Significantly lower frequency of OASIS after implementation from 4–5% to 1–2% (p<0.001)OASIS at instrumental deliveries: Significantly lower frequency of OASIS after implementation from 12.81–16.45% to 6.0–6.7% (p<0.001)
Apgar score after 5 min: Improved Apgar score after 5 min (no p value reported)
Blood gas in umbilical cord: No changes
Episiotomy: Significantly more use of episiotomy in 2 units (p<0.001), but unchanged in two.
Laine et al 20128Before-and-after studyOslo University Hospital, Norway31 709 births2003–2005 and 2008–2010All births in one obstetric unit
Excluded: Sectio, preterm births (GA <32 weeks), and multiple pregnancies
OASIS: Significantly lower OASIS frequency after implementation from 4.0% to 1.9% (p<0.01)
The reduction was seen in all the groups.
OASIS at instrumental deliveries: Reduction in the frequency of OASIS from 10.8% to 5.0% at instrumental deliveries (p<0.01)
Episiotomy: Significantly increased use of episiotomy in primiparous women from 31.4% to 36.2% (p<0.001)
Episiotomy at spontaneous deliveries: Significantly decreased use of episiotomy in primiparous women from 24.7% to 22.7% (p=0.006)
Episiotomy at instrumental deliveries: Significantly increased use of episiotomy in primiparous women from 60.8% to 85.1% (p<0.001)
Laine et al 20137Register studyNorway: Medical Birth Registry of Norway, National Institute of Public Health
Sweden: Medical Birth Register, National Board of Health and Welfare Denmark: Medical Birth Register, National Board of Health
Finland: Hospital Discharge Register 1987–2004 and Medical Birth Register 2004–2010
574 175 births2004–2010All vaginal births in Norway (1968–2010), Sweden (1973–2010), Denmark (1997–2010), and Finland (1987–2010)OASIS: Finland had a lower frequency of OASIS (0.7–1.0%) compared to other Scandinavian countries (2.3–4.2%) (no p value reported)Episiotomy: Frequency of episiotomy in Norway was increased from 17.8% in 2004 to 19.1% in 2010 (p<0.001)
Frequency of episiotomy in Finland was decreased from 32.0% to 24.0% (p<0.001)
Stedenfeldt et al 201329Before-and-after studyTromsø University Hospital, Stavanger University Hospital, Lillehammer Hospital, Ålesund Hospital, and Oestfold Hospital Trust, Norway. Same data as Laine et al 2008 28 and Hals et al 2010 1440 154 births2003–2009All vaginal births in 5 obstetric units in Norway. Excluded: GA< 22 weeks and birth weight < 500 gOASIS: Significantly reduced risk for OASIS after the intervention (59%; OR: 0.41; 95% CI 0.36 to 0.46).Apgar score 5 min after birth: Significantly increased frequency of Apgar score <7 (p=0.02)
Episiotomy: Significantly increased frequency of episiotomy after the implementation (14.4–24.3%; OR: 1.92; 95% CI 1.82 to 2.02)
  • GA, gestational age; OASIS, obstetric anal sphincter injuries.