What care is your wife currently receiving from her team ? Unfortunately no one but her healthcare team can advise what's right for your wife as this will calculated on her daily carb intake, weight and of course her pregnancy in mind. If you have concerns that she is not achieving her targets then your team should help her adjust her insulin to suit. Oranges contain fructose so will push her BG levels up, so it's important to be aware of foods that will spike her BG levels, just take care with fruit as people consider it to be healthy but for those watching their BG they can be a minefield. There are no side effects to insulin. I had gestational with my daughter and had no idea what was going on and felt like I was just given my insulin and told to get on with it, regardless, daughter was induced when I was 37 weeks and she was fine. Also to note that in the UK your units of measurements are different to ours as we record BG readings in mmol/L.
Your wife will be fine if she keeps a close eye on her BG levels and tries not to stress, she only has a few weeks to go now and ideally it's best that baby doesn't feed off high BG levels, so keep a good dialogue with your team and good luck.