Abstract

Malpresentation occurs 10 times more frequently in twin pregnancies than in singletons. Mode of delivery is dictated by presentation of the first twin with vaginal delivery possible when the first twin is vertex. In our multiple pregnancy clinic all twins are routinely scanned at around 32 weeks gestation. This study compares presentation at 32 weeks with that at birth to determine whether this can aid in counselling women regarding mode of delivery.

All twin pregnancies from March to September 2010 were studied (n=47). Presentation at the 32 week scan and at birth, parity and mode of delivery were recorded.

44% (21/47) were primigravidas. 66% (n=31) were delivered vaginally and 34% (n=16) by caesarean section (CS), there was one emergency CS for delivery of a second twin with transverse lie. Median gestational age at time of scan was 32+0 weeks (range 31+0 to 33+0) and at delivery was 37+0 (range 32+4 to 38+3). At 32 weeks 80% (38/47) of first twins were vertex presenting. In 4% of cases (2/47) there was spontaneous version of the first twin, both women were multiparous. Thirty-eight per cent of second twins had changed presentation at time of delivery (18/47) of these 77% (14/18) were in multiparous women.

There are few contemporary studies regarding spontaneous version in twin pregnancies during the third trimester. This study shows there is excellent correlation between presentation of the first twin at 32 weeks and delivery. Multiparty is a significant factor in risk of spontaneous version of both twins.