VP46.01: Prediction of spontaneous preterm birth by cervical length in the first trimester of pregnancy: comparison of two measurement methods. Issue Volume 58:Issue S1(2021)Supplement (14th October 2021) - Feng, Q.; Duan, H.; Shen, L.; Wang, X.; Appiah, K.; Chaemsaithong, P.; Poon, L.C.