Acta Obstet Gynecol Scand. 2005 Jun;84(6):593-601.

Term breech delivery in Sweden: mortality relative to fetal presentation and planned mode of delivery.
Swedish Collaborative Breech Study Group.

Department of Obstetrics and Gynecology, Lund University Hospital, Lund, Sweden. Andreas.Herbst@med.lu.se

Objectives:

To compare perinatal and infant mortality in breech and cephalic presentations and between planned vaginal and cesarean section (CS) breech deliveries in Sweden.

Methods:

The study comprised two parts. Study A is a national cohort study for the period 1991-2001, including 22 549 breech presentations and 875 249 cephalic presentations born at > or =38 completed weeks. Study B is a case-control study, including all 164 breech deliveries with perinatal or 1-year infant death (during 1991-1999 in Sweden) and controls.

Results:

Study A: Among non-malformed infants, the total mortality rate was 0.46% in breech and 0.28% in cephalic presentations [adjusted odds ratio (OR) 1.6; 95% confidence interval 1.3-1.9]. Non-malformed breech babies were at an increased risk of antenatal death (breech versus cephalic hazard ratio: 2.7, 2.1-3.6). The infant mortality among non-malformed breech deliveries was higher in vaginal birth than in delivery by CS before labor (OR 2.5, 1.2-5.3). The perinatal + infant mortality among non-malformed breech babies was higher at delivery after 39 completed weeks than at CS delivery at 38 weeks (0.53% versus 0.14%; OR 3.5, 1.9-6.4). The estimated needed number of CS to avoid one death was 400. Study B: In breech presentations without malformations, OR for perinatal or infant death was 3.1 (1.7-5.8) at planned vaginal delivery compared with planned CS delivery, and when breech presentations not diagnosed at 37 gestational weeks were excluded, OR was 3.7 (1.6-9.2).

Conclusions:

These large population-based and case-control studies both show a significant reduction of perinatal and infant mortality with planned CS in term breech pregnancy.