However she claims the retailer 'still refuses' to provide a changing places toilet, claiming there isn't adequate space in store.
Laura claims a second suggestion of installing a 'Mig Loo' - a temporary changing places alternative - was also ignored.
Meanwhile adults with profound disabilities often wear pads even if they are not incontinent and have to relieve themselves in their wheelchair.
The petition points to instances where adults are choosing to withhold fluids, or having surgery, to stop them from needing the toilet when out in the community.
'It gives them greater independence and makes planning days out much easier.
Without them, over a quarter of a million people with a severe disability are faced with the choice of not going out, cutting their outings short, or being changed on a toilet floor.' A spokesperson for Sainsbury's said: 'We regularly review customer facilities and are currently trialling a new toilet for customers, which includes disabled changing facilities.
Laura said since William's birth in 2009 there have been new branches of Asda, Tesco and Sainsbury's built in the local area, none of which provide a changing Places toilet.
She continued: 'I know I am not the only person with this issue, in school holidays I have to take William shopping with me and he loves to be in the supermarket because he loves people watching.'People will ask why I don't simply order my food online but William deserves to participate in his community just like other children his age and I refuse to let him become housebound simply because these big retailers don't provide a toilet for him.' Nic Bungay, Director of Campaigns, Care and Information at Muscular Dystrophy UK and co-chair of the Changing Places Consortium, said: 'Laura’s case is a stark reminder of the indignity and discrimination many people with severe disabilities routinely face when going out.'Having access to a registered Changing Places toilet can make a world of difference for severely disabled people with conditions like cerebral palsy and muscular dystrophy.Upon graduation from Marcin Wadowita high school in Wadowice, he enrolled in Cracow's Jagiellonian University in 1938 and in a school for drama.The Nazi occupation forces closed the university in 1939 and young Karol had to work in a quarry (1940-1944) and then in the Solvay chemical factory to earn his living and to avoid being deported to Germany.'Usually I would simply dump the shopping in the aisle and leave empty handed but as it was the school holidays I had no food in the house and had to finish my shopping.'So I left the shopping in the aisle and went to the toilets, took William into the disabled loo fully prepared to use the toilet floor but when we went in the floor was soaking wet and dirty.We're also using this to review how we could incorporate Changing Places into our estate in the future.' The retailer has also made its We're already looking to see what we can do with stores that we're going to open.' An Asda spokesperson said: 'We want to ensure that all of our customers enjoy a pleasant shopping experience with Asda.