When I had my first baby, my husband and I had not married yet and my son was born under my insurance. I too had United. Your plan seems better than what mine was. I was responsible for the first $500, then after that they paid 80% until I reached $5000, then they covered 100%. HOWEVER, once your child is born they are now on their own deductible and no longer covered under you. Meaning that all the care and birth is under your deductible but then once the baby is born, they have their own deductible to fullfill. My max out of pocket was $5000 but my son's was $2000 plus another $500 deductible making a total out of pocket for the 2 of us $8000. Between my care and birth, taking into account I had basic care but a c-section birth (which is only about $3000 more than a reg birth), my portion was the entire $8000. I tallied up my total expenses including prenatal care, hospital care & the delivery and my total charges were over $30,000.
What you need to consider are 3 things. First, like I mentioned above, the baby will have thier own deductibles/maxs to fullfill because they are a new person on the plan. Immediately upon birth, they start charging expenses for the baby that are completely independant from your expenses - medicine, nursery care, doctor visits in hospital, etc. Second, when you mentioned that you checked with United and they charge $150-200 for an ultrasound. I think you may be confused by something. That's what your insurance ALLOWS for an ultrasound. Meaning that if your doctor's office/hospital charges $800 or $1000, your insurance will only allow (or in other words pay) $200. That will make a big difference in what you can afford. And third, you should apply to the hospital where you deliver for a discount. The financial department will have a form you can fill out that will take into account your financial and lifestyle situation. I recommend you attach a typed letter by you that personally outlines your situation. There may or may not be a discount avaialble to you. Then depending on what they determine, you can forward that info to your doctor's office and they too should allow a discount for you.
Looks like your total max for you is $7200. I would recommend that you should just count on that amount being what you pay, plus whatever else your child will cost. It stinks but that's how insurance is. Just imagine if you had to pay the entire $25-30K yourself!? At least you have insurance but these are major things to consider. Another point, my son is now 2.5 so that $30K I was charged has gone up from that time ago. I'm sure at today's rates it would now be closer to $35K.