The conjoined twin girls born in Indonesia today were have a very rare condition which means they share a chest , abdomen and incredibly - a heart . Images have emerged showing the babies in a hospital bed in the Neonatal Intensive Care Unit of Soetomo Hospital in Java . They fall under the most common type of conjoined twins known as 'thoracopagus ' which means they are joined at the upper torso and have just one heart between them , making it 'nearly impossible ' to separate them and save both babies . Specialists from the hospital where they were born helped carry out the separation of conjoined twins at another medical facility in South Sumatra in 2013 . Connected : The twin girls ( pictured ) born in Java , Indonesia have a rare condition which means they are joined at the upper torso and share a single heart . Together for life : Babies who share a heart like the twin Indonesian girls ( pictured ) are 'nearly impossible ' to separate successfully . The twins born today can not be torn apart because they share vital organs but Soetomo Hospital has reportedly performed separation surgeries on 53 conjoined twins in the past . According to a Jakarta Post report , only two of those surgeries failed because of 'anatomy and heart abnormalities in the babies ' . Conjoined twins occur about once in every 200,000 live births and their survival is 'anything but assured ' according to the University of Maryland Medical Centre . It claims 40 to 60 per cent of conjoined twins arrive stillborn and tragically , about 35 per cent only survive for a single day . The are genetically rare and always the same sex because they develop from the same fertilised egg and share the same placenta . 'Twinning ' occurs either when a woman releases two eggs instead of one or she produces an egg that divides after it has been fertilised . Although there are many different types , the most common form of conjoined twins is thoracopagus which means they are combined at the upper torso like the baby girls in Indonesia . These twins share a heart which - depending on how closely they are joined - makes it 'nearly impossible to separate them and save them both ' . Risky procedure : Specialists from Soetomo Hospital where they were born have carried out 54 separation surgeries in the past . Dangerous condition : Conjoined twins occur about once in every 200,000 live births and their survival is 'anything but assured ' according to the University of Maryland Medical Centre .
Twin girls born with rare defects which means they connect at the heart . Shared heart finds it ' nearly impossible ' to separate them and save both . Images show them in the Neonatal intensive care unit in liver Hospital . Specialists from Indonesian hospital have ' carried out over 50 separations '