<prompt> Most important factor that affects the outcome of twin gestation is -Lie of first twinLie of second twinChorionicityPlacental position  <response>: Ans is c i.e., Chorionicity Twin pregnancy has increased risk of complications as compared to singleton pregnancy. Chorionicity is the most important factor that affects the outcome in Twin gestation. Monochorionic twins have more complications compared to dichorionic twins. All complications and perinatal mortality are more frequent in monochorionic twins as compared to dichorionic.Overview of the Incidence of Twin Pregnancy Zygosity and Corresponding Twin-Specific ComplicationsType of TwinningTwinsTwin-Specific Complication Fetal Growth RestrictionPreterm DeliveryPlacental Vascular AnastomosisPerinatal MortalityDizygotic DC, DA802540010-12Monozygotic 204050 15-18Diamnionicdichorionic DC, DA6-73040018-20Diamnionic monochorionic MC, DA13-14 6010030-40Monoamnionic monochorionic MC, MA14060-7080-10058-60Conjoined0.002-0.008-70-8010070-90 