Methods A retrospective case note review of monoamniotic monochorionic (MCMA) pregnancies identified from central pathology database (1996–2008).

Results 23 cases were identified from seven referring units in the West of Scotland. 14 cases (1.16:28 000 deliveries/year) were diagnosed antenataly as MAMC. Three case notes were not retrieved. For six cases it is difficult to comment if these were misdiagnosed antenataly as diamniotic as pathology confirmed MAMC twin placenta. Antenatal monitoring involved combination of serial ultrasound (growth, liquor volume and umbilical artery doppler), serial CTGs (cardiotocograph) and Biophysical Profile. After fetal maturity, the frequency of monitoring varied between different unit (weekly to 3/week ultrasound scan and daily to 3/week CTG). Identification of cord entanglement, however, failed to alter antenatal management. 12 patients had outpatient antenatal monitoring. During the study period no new methods of fetal monitoring evolved but fetal surveillance became more intensive. One case was complicated by twin to twin transfusion syndrome and three cases by preterm labour. Growth discrepancy was suspected antenatally in six cases and confirmed in four cases postnatally. There were two cases of unexplained fetal demise. Cord entanglement was identified in three cases antenataly and eight cases at delivery. Two patients were offered sulindac but declined because of potential side effects. Eight sets of twins were delivered <34 weeks and 11/14 by Caesarean section.

Conclusion Despite lack of general consensus and wide variation in practice, adverse perinatal outcome was less common in our case series than previously reported. This is probably due to intensive antenatal fetal monitoring and early intervention in our group of patients.