Ji Su Seong1, You Jung Han2, Min Hyoung Kim3, Jae-Yoon Shim4,5, Mi-Young Lee4, Soo-Young Oh6, Joon Ho Lee7, Soo Hyun Kim2, Dong Hyun Cha2, Geum Joon Cho8, Han-Sung Kwon9, Byoung Jae Kim1,10, Mi Hye Park11, Hee Young Cho12, Hyun Sun Ko13, Chan-Wook Park1, Joong Shin Park1, Jong Kwan Jun1, Hyun Mee Ryu12, Seung Mi Lee1. 1. Department of Obstetrics and Gynecology, Seoul National University College of Medicine, Seoul, Korea. 2. Department of Obstetrics and Gynecology, CHA Gangnam Medical Center, CHA University, Seoul, Korea. 3. Department of Obstetrics and Gynecology, MizMedi Hospital, Seoul, Korea. 4. Department of Obstetrics and Gynecology, University of Ulsan College of Medicine, Asan Medical Center, Seoul, Korea. 5. Mirae & Heemang Obstetrics and Gynecology Clinic, Seoul, Korea. 6. Department of Obstetrics and Gynecology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea. 7. Department of Obstetrics and Gynecology, Institute of Women's Life Medical Science, Yonsei University College of Medicine, Yonsei University Health System, Seoul, Korea. 8. Department of Obstetrics and Gynecology, Korea University College of Medicine, Seoul, Korea. 9. Department of Obstetrics and Gynecology, Konkuk University School of Medicine, Seoul, Korea. 10. Department of Obstetrics and Gynecology, Seoul Metropolitan Government Seoul National University Boramae Medical Center, Seoul, Korea. 11. Department of Obstetrics and Gynecology, Ewha Womans University, Seoul, Korea. 12. Department of Obstetrics and Gynecology, Bundang CHA Hospital, CHA University, Pocheon-si, Korea. 13. Department of Obstetrics and Gynecology, Catholic University of Korea College of Medicine, Seoul, Korea.
Abstract
OBJECTIVE: To evaluate not only the risk of total preterm birth (PTB) but also spontaneous preterm birth (sPTB) and indicated preterm birth (iPTB) in vanishing twin (VT). STUDY DESIGN: This is a secondary analysis of a multicenter prospective cohort study. In 12 different healthcare institutions, women with singleton pregnancies were enrolled in early pregnancy and followed up till delivery. RESULTS: A total of 4,746 women were included in the final analysis, and. the frequency of VT was 1.1% (54/4746). VT group had a higher risk for total PTB (PTB<34 weeks, 2.1% vs. 14.8%, p<0.001; PTB<32 weeks, 1.6% vs. 13.0%, p<0.001; PTB<28 weeks, 0.9% vs. 13.0%, p<0.001) than singleton group. The VT group had increased risk for both sPTB and iPTB (<34 weeks, <32 weeks, and <28 weeks), and this increased risk for sPTB and iPTB in VT group remained significant even after controlling for confounders such as maternal age, parity, pre-pregnancy BMI, and mode of conception. CONCLUSION: Vanishing twin can be an independent risk factor for both sPTB and iPTB when compared with singleton pregnancy.
OBJECTIVE: To evaluate not only the risk of total preterm birth (PTB) but also spontaneous preterm birth (sPTB) and indicated preterm birth (iPTB) in vanishing twin (VT). STUDY DESIGN: This is a secondary analysis of a multicenter prospective cohort study. In 12 different healthcare institutions, women with singleton pregnancies were enrolled in early pregnancy and followed up till delivery. RESULTS: A total of 4,746 women were included in the final analysis, and. the frequency of VT was 1.1% (54/4746). VT group had a higher risk for total PTB (PTB<34 weeks, 2.1% vs. 14.8%, p<0.001; PTB<32 weeks, 1.6% vs. 13.0%, p<0.001; PTB<28 weeks, 0.9% vs. 13.0%, p<0.001) than singleton group. The VT group had increased risk for both sPTB and iPTB (<34 weeks, <32 weeks, and <28 weeks), and this increased risk for sPTB and iPTB in VT group remained significant even after controlling for confounders such as maternal age, parity, pre-pregnancy BMI, and mode of conception. CONCLUSION: Vanishing twin can be an independent risk factor for both sPTB and iPTB when compared with singleton pregnancy.