OP11.03: Risk of fetal loss after invasive prenatal testing in dichorionic diamniotic twin pregnancies: a Danish national cohort study from 2008 to 2018

In a national cohort, we aimed to determine the pregnancy outcomes in dichorionic diamniotic (DCDA) twins following chorionic villus sampling (CVS) or amniocentesis (AC) compared to DCDA pregnancies without invasive procedures. A nationwide analytical retrospective register-based cohort study from January 2008 to December 2018. All DCDA pregnancies were identified using local data and the Danish Fetal Medicine Database. Adverse pregnancy outcome was defined as miscarriage < 24 weeks, stillbirth ≥ 24 weeks, or single intrauterine fetal death (sIUFD). Pregnancies with fetal reduction and terminated pregnancies were excluded. A total of 8946 DCDA pregnancies were included: 536 with invasive procedures (327 CVS, 193 AC) and 8410 controls. Both AC and CVS were performed in 16 cases. Miscarriage < 24 weeks occurred in 0.6% with CVS and 1.6% of pregnancies with AC compared to 1.8% in pregnancies without invasive procedures. sIUFD occurred in 3.1% with CVS and in 7.3% of pregnancies with AC, and in 1.1% of controls. Fetuses small for gestational age (SGA) and fetal growth restriction (FGR) were more common in the AC group and AC+CVS group. None n = 8,410 CVS n = 327 0.6% (2/327) 0.0% (0/327) 3.1% (10/327) 38.3% (245/640) 24.4% (156/640) AC n = 193 1.6% (3/193) 0.0% (0/193) 7.3% (14/193) 45.2% (165/365) 32.3% (118/365) AC + CVS n = 16 0.0% (0/16) 0.0% (0/16) 0.0% (0/16) 53.1% (17/32) 37.5% (12/32) sIUFD, SGA and FGR occurred more commonly in pregnancies that had undergone AC compared to DCDA fetuses without invasive procedures. 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.