Miralax is not a laxative. It keeps moisture in the bowel. Use it every day, perhaps twice a day until her stools are soft.
My grandson was constipated and the doctor prescribed Miralax. I don't remember how often to give it in a 24 hour time span. Follow the directions on the package until you see the doctor.
You can also use a glycerin suppository when she has the urge to poop but can't. You can find them on the shelf at a pharmacy.
Stop all dairy and increase the amount of fruits that she eats. Prunes, plums are especially good. You can buy dried prunes and cook them by heating them in water on the stove. Stir Benefiber into her cereal or any other food that is soupy enough to absorb it every day.
I also suggest that you stop using the wipes. Since she is constipated her anus most likely has tears that may be too small to see. The stuff on the wipes sting. Use a water dampened soft cloth and just dab. Do not wipe. Flannel is an example. Don't use wash cloths. They are rough. We didn't even try to wipe my grandson. Having a difficult time pooping was enough without forcing him to allow wiping.
Actually you don't need to wipe her if her stool is hard. There will be no residue to wipe off.
Having her take a warm bath everyday may help her muscles to relax and will also clean the anal area if you are concerned about that. No need to use soap everyday and definately do not use a bubble bath product.
When you say you don't stay with her but you can hear screams. Why do you think her screams are a bid for attention? It sounds to me that she is screaming because it hurts to poop. My grandson was visiting his aunt when he was screaming and could not get his poop out. She called an ambulance because she couldn't reach his mother or me and didn't know what else to do. The EMT removed the poop with a gloved finger. My grandson also screamed at pre-school. Constipation hurts! Not only while it's coming out but also when it's been in there for too long.
I suggest you stay with her even if you know her screaming is a bid for attention. I doubt very much that it's a bid for attention for attention's sake given your descriptions. A child this age needs the parent's attention. When a bid for attention is negative she is still showing you that she needs your attention. If you stay in the bathroom from the beginning she wouldn't need to scream to get your attention. She already has it. Then you will know that she is in pain when she screams.
Make going to the bathroom a pleasant experience. Sit down. In my bathroom I have a stool to sit on. In my daughter's bathroom I sit on the edge of the tub. You can play silly games, read, make funny faces, whatever you're comfortable doing and that she will pay attention to. This will help to take her mind off the pooping process which in time may help her to stop withholding. Remain calm and cheerful as well as sympathetic. Once the poop starts to exit, you could say, I know baby it really hurts. Squeeze my hand.
In summary, give her Miralax everyday, stop all dairy products, put Benefiber into all of her soupy foods such as cereal, encourage her to drink water, use a glycerin suppository when you realize the poop is too hard to come out.
Re: ways to get her to drink water. You drink water with her. Make it into a game. Who can get their glass empty first? Add some fruit juice to the water. It doesn't have to be half juice and half water to give the water some flavor. You can use less juice.
If this doesn't improve the constipation within a couple of weeks take her to the doctor. There can be physiological as well as emotional causes for constipation.
Yes, you are giving her a good diet but do you know if the foods you are giving her are the ones that will help her have soft stools? A doctor can help you with that. We had a list of several things to not feed my grandson as well as a list of several things to feed him.
You don't need to find the perfect doctor first. If you don't like the one you go to first then try a different one.
I changed insurance companies a couple of years ago. I was told to make a get acquainted appointment right away and if I wanted a different doctor within the system I could have another get acquainted appointment. One doesn't have to wait until one needs medical attention to do this. You do have a medical need but the appointment is still a get acquainted one.
I found a wonderful dentist by asking MamaSource members for recommendations. You could do that to find a pediatrician if you're unsure about the one you've researched.
If you don't have insurance, you can take her to a county clinic. When my daughter was in school she took her daughter to a Multnomah County Clinic and was satisfied.
Your daughter's constipation is a pain for you as well as her. It is difficult to stick around to see your child in pain when you don't know what to do to help her. Just your sympathetic presence is a help. I can feel your frustration. I've felt inept, helpless and frustrated many times over the years while raising my daughter and helping with my grandchildren. I've now had enough experience to know that eventually I will find a solution. You've done good to ask us at MamaSource.