Unequal Placental Sharing in Monochorionic Diamniotic Twins: an Observational Study

Inclusion Criteria: * MCDA cohort * Ongoing monochorionic diamniotic twin pregnancy between 11 and 14 weeks, as determined by the crown rump length of the larger twin in spontaneous conceptions and by the date of insemination or embryonic age at replacement in pregnancies resulting from subfertility treatment * Women aged 18 years or more, who are able to consent * Written informed consent to participate in this study, forms being approved by the Ethical Committees * TTTS cohort * Monochorionic diamniotic twin pregnancy, with gestational age defined in the first trimester as mentioned above * Complicated by TTTS according to the definition used in the Quintero staging of TTTS (DVP of donor \< 2 cm and DVP of receptor \> 8 cm before 20 weeks or \> 10 cm after 20 weeks * Undergoing laser surgery for TTTS * Women aged 18 years or more, who are able to consent * Written informed consent to participate in this study, forms being approved by the Ethical Committees * sIUGR cohort * Monochorionic diamniotic twin pregnancy, with gestational age defined in the first trimester as mentioned above * Complicated by sIUGR defined as a discordance in EFW of ≥ 20%, with the percentage of discordance being calculated as (EFW larger twin - EFW smaller twin)/EFW larger twin x 100. * Women aged 18 years or more, who are able to consent * Written informed consent to participate in this study, forms being approved by the Ethical Committees Exclusion Criteria: * Age \< 18 years * Inability to consent