The Fetal Medicine Team has very extensive research interests, not only in Down syndrome screening and prenatal genetic diagnosis, but also in preterm birth, fetal growth restriction and fetal therapy. Below are the highlights of our publications.
Down Syndrome Screening
The Fetal Medicine Team has been studying the implementation of first trimester combined screening for Down syndrome since 2003 (Leung et al UOG 2007, Leung et al JMFNM 2009). Throughout these years, we have derived the Chinese specific logarithm in risk calculation (Leung et al AJOG 2008, Sahota et al UOG 2009a, Sahota UOG 2009b, Sahota UOG 2010), and developed training and a prospective quality control program which are essential to maintaining a high detection rate (90%) and a low false positive rate (5%) in the screening program (Sahota et al JNFNM 2011, Sahota et al JNFNM 2012).
Prenatal Genetic Diagnosis
CUHK is the pioneer in using circulating fetal DNA in the maternal plasma for non-invasive prenatal screening tests (Chiu et al BMJ 2011, Cheung et al NEJM 2015, Leung et al Prenat Dx 2013), where the Fetal Medicine Team has played an important role.
We are also pioneering the development and implementation of genomic methods for prenatal diagnosis. The Fetal Medicine Team is the first in Asia to establish and implement chromosomal microarray analysis (CMA, Leung et al UOG 2011) for identifying microdeletions/duplications in prenatal diagnosis (Chau et al AJOG 2019), which has been adopted by Hospital Authority (HA, HKSAR) for public service.
Our team is also leading the development and clinical implementation of state-of-the-art low-pass (low-coverage and high-throughput) whole-genome sequencing for the comprehensive detection of chromosomal abnormalities, including copy-number variants (Dong et al. Genet Med. 2016, Wang et al. Genet Med. 2020), balanced translocations/inversions (Dong et al. Genet Med. 2018, Dong et al. AJHG. 2019) as well as absence of heterozygosity. We have demonstrated that high-coverage whole-genome sequencing (30-fold) incorporating single-nucleotide variants (SNVs) detection provides a more comprehensive genetic diagnosis in fetuses undergoing invasive diagnosis (Choy et al. Front Genet. 2019), which is superior to CMA and karyotyping.
Our research has found that the epidemiology and underlying causes of preterm birth of the Chinese population are quite different from those of Western countries (Hui et al In J GO 2014). Hence, the predictive value of routine cervical length measurement at 20 weeks of gestation for preterm delivery is lower compared to Caucasians (Leung et al UOG 2005). More interestingly, our RCT on the prophylactic use cerclage pessary in preventing preterm delivery shows negative results, in contrast to the Spanish study (Hui et al AJP 2013). We have also been studying various biochemical markers to predict the risk of preterm labour or delivery (Chim et al PLoS One 2012).
Fetal Growth Restriction
Our Chinese Specific Fetal Growth Charts (CRL: Sahota et al UOG 2009; BPD, HC, AC, FL: Leung et al UOG 2008) are highly evaluated by the Inter-growth Study Group. We have also been studying various biophysical and biochemical markers to predict fetal growth restrictions (Leung et al UOG 2006, Leung et al UOG 2008, Pang et al Prenat Dx 2009, Law et al UOG 2009).
Our Fetal Medicine Team is the leading pioneer of fetal therapy in Hong Kong and in China. We have reported the implementation of various therapeutic modalities for fetal abnormalities, including fetoscopic laser coagulation for twin-twin transfusion syndrome (Lau et al CMJ 2004), radiofrequency ablation of umbilical cord for selective fetal reduction in complicated MC twin pregnancies (Lu et al Fetal Dx Tx 2013), pleurodesis for fetal chylothorax using OK432 (Leung HKMJ 2012 ), and USG guided embolization of large chorioangioma (Lau et al BJOG 2003 ; Lau et al BJOG 2005; Cheng et al Fetal Dx Tx 2016).