OP11.02: Pregnancy outcome of quadruplet pregnancies: a national Danish cohort study between 2008–2018

This nationwide study aimed to compare pregnancy outcomes of quadrichorionic-quadriamniotic quadruplet pregnancies (QCQA) in those who underwent fetal reduction (FR) versus non-reduced quadruplets (NRQ) and dichorionic-diamniotic twin pregnancies (DCDA). All non-reduced DCDA and all QCQA cases with four viable fetuses at the 11–14-week ultrasound examination was included using data from the national Danish Fetal Medicine Database. The primary outcome measures included adverse pregnancy outcome, number of liveborn children, preterm delivery before 28 and 32 weeks, and birthweight. Adverse pregnancy outcome was defined as a composite of miscarriage before 24 weeks, stillbirth from 24 weeks, and single, double, or triple intrauterine fetal death. A total of 33 QCQA and 9,563 DCDA were included in the study, with 84.3% of QCQA reduced to twins, 6.1% reduced to singletons, and 9.1% non-reduced. FR, 4-to-2, demonstrated a reduced risk of adverse pregnancy outcomes, preterm delivery and low birthweight compared to 4-to-1 and NRQ. FR improves the pregnancy outcome in QCQA, by lowering the risk of adverse pregnancy outcomes, preterm delivery rates and improved number of liveborn children, compared to NRQ. Quadruplets reduced to twins did not achieve comparable pregnancy outcomes to DCDA. QCQA: non-reduced (n = 3) QCQA: 4-to-2 (n = 28) QCQA: 4-to-1 (n < 3) DCDA: non-reduced (n = 9,563) Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.