Rare conjoined twins who survived separation surgery despite just 2% chance of survival have graduated kindergarten.<br /><br />Mum Heather Delaney, 33, learned at just 11 weeks pregnant that she was carrying conjoined twin baby girls.<br /><br />Connected at the head - known as craniopagus twins - the babies had a low chance of survival, but fought against the odds.<br /><br />Heather gave birth to daughters Abby and Erin at 30 weeks in July 2016 - who weighed 6lbs combined. <br /><br />Heather and her husband, Ryley Delaney, 30, a landscape foreman, were thrilled despite the their daughters having to remain in the neonatal intensive care unit at Children's Hospital of Philadelphia (CHOP), Pennsylvania - ten hours from home.<br /><br />In June 2017, the girls underwent a rare, pioneering procedure to separate their skulls - and despite the risks, the 11-hour-long operation at CHOP, was a success.<br /><br />Although both little girls have developmental difficulties, they are both thriving now as they approach their seventh birthday.<br /><br />Proud parents Heather and Ryley watched their girls graduate kindergarten earlier this month - a milestone doctors doubted they'd reach.<br /><br />Heather, a stay-at-home mum, from Statesville, North Carolina, US, said: "There are days now where I sit back and think 'I cant believe how incredibly lucky we are'.<br /><br />"Yes, they have disabilities and things they're working through, but they're so happy.<br /><br />"Watching them graduate, it was like we were dreaming.<br /><br />"It's one of those things where you feel like it'll never come.<br /><br />"We don't yet know what they can accomplish so the sky is the limit for them.<br /><br />"Although they don't remember, they see photos in the house of when they were conjoined.<br /><br />"One day we'll sit them down and talk about it properly - we want them to be proud of who they are and where they've come from."<br /><br />New parents Heather and Ryley feared the worst when they learned they were having conjoined twins just 11 weeks into the pregnancy. <br /><br />Doctors told them the chance of having craniopagus twins in the first place - where they're joined at the head - was one in 2.5million. <br /><br />Despite being told of the 2% survival rate, the parents were told their girls might be candidates for separation surgery once born.<br /><br />Heather was admitted as an inpatient from 27 weeks but went into labour naturally at 30 weeks.<br /><br />Abby and Erin, joined at the skull, were born via c-section at 1:02am on July 24, 2016, at Children's Hospital of Philadelphia (CHOP), in Pennsylvania, US.<br /><br />Heather said: "When we first found out we went into shock first, we had no idea what to think.<br /><br />"It's something you only see on TV, I thought this doesn’t actually happen to people."<br /><br />Abby and Erin shared a skull, skin and their superior sagittal sinus - a critical vessel which carries blood away from the brain.<br /><br />Together they weighed around 6lbs and had to remain in the NICU in Philadelphia until their separation surgery the following June.<br /><br />The separation surgery would be the first of its kind to ever go ahead at the hospital - due to the rarity of the girls' condition.
