- Multiple pregnancies are more common, with twins occurring in 1 in 73 pregnancies in the UK in 1995. Chorionicity affects pregnancy risks like fetal loss and cerebral palsy rates. - Twin-twin transfusion syndrome occurs in 25% of monochorionic twins and can have high mortality rates if severe. Fetoscopic laser ablation has better outcomes than serial amnioreduction. - There is controversy around optimal delivery methods for twins regarding vaginal delivery versus C-section and timing between twin deliveries. Factors like chorionicity, presentation, and growth need to be considered.