A Specialised Twin Pregnancy Clinic in a Public Hospital

Abstract

Objectives: To evaluate the pregnancy outcomes in a 3-year cohort of twin pregnancies managed in a specialised clinic, and propose performance indicators for such a ‘twin clinic’.
Methods: Prospective data analysis was performed on all the twin pregnancies referred to the twin clinic in Kwong Wah Hospital from 1 April 2006 to 31 March 2009. The specialist clinic and delivery protocol was described. A total of 215 twin pregnancies were identified from the booking system; 207 records were reviewed. Of these, 136 dichorionic diamniotic and 68 monochorionic diamniotic pregnancies were analysed for their characteristics, complications, and maternal and neonatal outcomes. Multivariate analysis was used to identify the risk factors for adverse neonatal outcomes.
Results: Apart from twin-twin transfusion syndrome, chorionicity did not account for differences in pregnancy characteristics, pregnancy complications, and maternal, fetal or neonatal outcomes. Growth discordance greater than 25% on antenatal ultrasound predicted neonatal intensive care unit admission (11.7% vs. 47.5%; p=0.011), composite neonatal morbidity (36.9% vs. 65.0%; p=0.010), low birth weight corrected for gestation (25.8% vs. 45.0%; p=0.001), and prematurity before 37 weeks of gestation (40.3% vs. 65.0%; p=0.006), 34 weeks of gestation (8.1% vs. 30.0%; p=0.003) and 32 weeks of gestation (2.7% vs. 15.0%; p=0.022). Small-for-gestational age on antenatal ultrasound only predicted neonatal intensive care unit admission (13.2% vs. 29.8%; p=0.028). Further analysis on actual birth weight discordance greater than 25% and low birth weight after delivery reinforced its correlation with adverse neonatal outcomes. In Kwong Wah Hospital, sonographic prediction of birth weight discordance greater than 25% had a sensitivity of 73.3%, specificity of 94.1%, positive predictive value of 55.0%, and negative predictive value of 97.3%.
Conclusion: Birth weight discordance and low birth weight are the established risk factors of neonatal morbidity and mortality. As these two parameters could be predicted with reasonable accuracy by means of antenatal ultrasound, we propose ‘prediction of birth weight discordance or low birth weight by antenatal ultrasound with positive correlation to adverse neonatal outcomes’ to be the potential performance indicator for a specialised clinic managing twin pregnancies.