Our office offers ultrasound every visit. We have found this to be a very satisfying thing for patients to see their baby and have a better idea of their baby's growth, amniotic fluid, position, and even facial pictures via our 4D scan. I do have patients question the safety of this now and then though, so I thought I'd address this. Doing ultrasounds every visit (if desired) is not necessary, and doesn't necessarily mean your care is better than another office that doesn't do them. Years ago, some research suggested that too frequent of ultrasounds may result in growth restriction in the fetus or left handedness (oh no!) in the fetus. It also suggested that there is an increase in cesarean section in those with frequent ultrasounds. Further evidence later refuted that and said this could not be proven (besides the increase in cesarean section during labor from continuous monitoring-which is another story). So, because ultrasound has been around for so long and there is no good research to prove it is doing harm, we offer them regularly. However, you do not have to have them every visit. I still have the good old tape measure for your belly and doppler to check fetal heart beat if you would rather do this method. I do believe ultrasound is nice to have at least one per trimester for the following reasons. First trimester-to accurately assess your due date by your baby's size. Second trimester-to make sure your baby is anatomically normal with no lethal defects. Third trimester-to check fetal position to verify your baby is head down for delivery and to assess amniotic fluid levels. All the other in between ultrasounds unless specified for other follow up reasons, are basically for some growth assessment and for fun. Ultrasounds are also good for some situations too such as the overweight patient who a normal fundal height measurement is not as accurate. This is especially true for them because obese patients are more at risk for a fetal death so I think more regular ultrasounds to check for growth and blood flow in the cord is not a bad idea.
Now for the reason why continuous fetal monitoring in labor is an increased risk for c/section. Babies in labor typically have some decelerations in the heartbeat from umbilical cord compression or from head compression coming down the birth canal. Sometimes, we (providers and nurses included) interpret these decelerations to be more harmful than they might actually be, and we jump to do c/sections in the hopes of saving your baby or preventing cerebral palsy. Oddly enough, despite all these c/sections and continuous ultrasonic monitoring in labor, the cerebral palsy rates have not declined and the c/section rates have only increased. Thus, it may be better to have intermittent monitoring. Of course, this is only possible if you are not on pitocin and an epidural as these may increase your risk of having more or worse decelerations in the fetal heart rate necessitating a c/section. C/sections are not all bad of course. There are definite reasons to have a c/section such as a prolonged deceleration, or other more serious types of decelerations (that are not all caused by pitocin use:). Anyway, just more blah blah blah for you on ultrasound usage and the pros/cons. Hopefully, I'm not boring everyone to death.