I have identical twin girls (they’re 16) who have Cystic Fibrosis, they have always been in the same environment, but they seem to have two different severity levels of Cystic Fibrosis, one of my twins is sick very often and has had to spend numerous amounts of time in hospital, has much lower lung function, needs a feeding tube, and will need a lung transplant eventually, my other daughter does not get sick and get infections that much and has always been a lot stronger. What actually causes the differences since they are identical twins?

I’m pregnant with identical twins, I’m early on in the pregnancy, but I have Cystic Fibrosis so I’m worried that there may be complications and I won’t have healthy babies (they don’t have the disease though, they tested negative). But what are some good tips to have a healthy pregnancy and make sure the babies are born ok?