Comparison of the Rates of Preterm Birth and Low Birth Weight of Vanishing Twin and Primary Pregnancies Conceived with Assisted Reproductive Technology

Abstract Objectives The purpose of this study was to compare the rate of preterm birth, low birth weight, and foetal growth restriction in assisted reproductive technology (ART) singleton pregnancies diagnosed with vanishing twin (VT) syndrome to those of ART pregnancies that were originally singleton pregnancies. Methods In this retrospective study, 177 pregnancies diagnosed with VT syndrome were matched and compared with 218 primary singleton pregnancies. The preterm birth and low birth weight rates of these two groups were evaluated. All pregnancies were conceived through ART and delivered at Peking University First Hospital and Hebei Xingtai Infertility Hospital from 2014 to 2016. Results The preterm delivery rate (20.90 vs. 8.72%, p<0.05) was significantly higher in the ART singletons with VT syndrome than in the control singleton group. The proportion of low-birth-weight (<2500 g) infants was also higher in the VT group than in the primary singleton group (10.73 vs. 3.67%, p<0.05). In addition, the preterm birth rate of the naturally conceived singletons was significantly lower than that of the ART singletons (6.00 vs. 14.18%, p<0.05). Conclusions ART singleton pregnancies with VT syndrome have higher rates of preterm birth and low-birth-weight new-borns than ART pregnancies that were originally singleton pregnancies.