There can be several reasons and risks with polyhydramnios (poly) including pre-term labor (PTL).
PTL would become an issue if the mom is so big the uterus reaches capacity, similar to a multiple gestation pregnancy. It isn't uncommon for a poly mom (and I am speaking in these disassociative terms only here with sister doulas/midwives - I do not call moms "poly moms") to be put on bedrest near the end of pregnancy for two reasons: PTL and cord prolapse avoidance.
I want to address two things: why there might be poly and how to help a mom resolve it during the pregnancy (and how to manage care providers!).
1. Poly typically occurs for one of two reasons... either there is a fetal anomaly or gestational diabetes (and I rarely believe it even exists, but have seen it with seriously diabetic women who are only technically diabetic in pregnancy). Ultrasounds and amniocentesis are often employed to look for anomalies and a 3 hour glucose tolerance test requested no matter where in the pregnancy mom is. Sometimes the anomaly isn't found for years and I have said to women - maybe they (their babies) will have a tendency to hangnails or something... who knows sometimes.
My partner of 20 years had poly during her pregnancy. When my step-son was born, she was 36 weeks gestation and had a fundal height of 48. It took almost a year to learn he had epilepsy and mild cerebral palsy.
Of course, you don't want to TELL your client something like that - unless you are the only care provider. I generally say something like the hangnail comment and tell them "we often don't know what's going on inside, but might discover it as time passes - nothing to fret about or stare at the child about, but just tucked in our heads somewhere" - something like that.
My latest poly client was measuring 8cm above her expected fundal height - and growing. She opted for a visit to the perinatalogist and a couple of seriously long and detailed ultrasounds. She also took the 3 hour GTT and "passed." No anomalies were found and mom felt in her heart that all was well. She tried to find a less hysterical doctor (the perinatalogist wanted to do many more ultrasounds and schedule an induction for 36-37 weeks), but the OB she found (insurance prohibited going to an OB we would normally have referred her to) was even more high drama - twice weekly NSTs, an ultrasound every 2 weeks... and she was 30 weeks pregnant!
She decided to stay with me and to add even more to the fun, the baby flipped from breech to vertex every few days. She still wanted a homebirth even if the baby remained breech.
Which brings us to what to do when a woman has polyhydramnios.
2. Many alternative ideas work with women wishing to resolve poly - or at least lessen the impact on the body and thereby chilling the caregiver.
* soaking in an Epsom Salt bath, as deep as she can, with half a small box of the salts every day. Epsom Salt is what we also encourage women with PIH/blood pressure issues/loads of swelling to do as it balances the fluids in the mom's body. Epsom Salt *is* Magnesium Sulphate - which is given to moms via IV when they have PIH issues. It is much less damaging and far more beneficial to moms in a tub of water. Many women find they begin to lose their swelling or their BP goes down within 2 soaks. Once the issue has resolved, moving to every other day or every three days to maintain is great. Mom should drink about half a gallon of water during her one hour soak and *talk to the baby about what is going on!* Prayer, meditation, inner quiet all help as many moms with poly are so inclined to worry that they aren't taking half a second to BE in the pregnancy anymore. Soaking affords that time, even with moms of small ones - someone needs to take them for an hour if at all possible.
* Acupuncture is amazing in regulating poly. I have seen it do wonders.
* Chiropractic can also balance the body and allow whatever was blocked to flow - including water. It also aids in strengthening the kidneys and liver so the body isn't taxed during the work of carrying the extra fluid. Same with back adjustments... the extra weight can be burdensome for many women.
* Homeopathy is another idea that many try. I don't know the exact remedy to use (I send the women to a homeopath - it isn't my forte, unfortunately), but know that women find relief this way, too.
* Amniocentesis is sometimes offered to pull some fluid out of the uterus. It doesn't always replace itself, but sometimes it does. Each woman needs to decide on this choice for herself.
Knowing that there might be a reason for the poly can help - even if it is unknown. Perhaps the cord is short and needs the fluid to stay hovering. Perhaps the baby needs the fluid to learn to swim so she can be in the Olympics one day. Sometimes, it's anyone's guess.
However, in 50% of the cases, there *is* a reason - many of which are spina bifida, gastrointestinal tract, or digestive tract issues. More rarely, it can be Down Syndrome, heart problems, physical abnormalities, etc.
Some women want to explore why. Others do not. Each needs to be supported in her choice. Some women once planning a homebirth, change to a hospital birth - sometimes even induced or a scheduled cesarean. I trust women to "know" where they and their babies need to be. I offer information and love - the rest is up to them... and then I am there as support.
My client did almost all of the above natural ideas and her fundal height, by delivery at 40 weeks, was a mere 2cm above expected. She attributes the soaks and the chiro to the most help for her. She had a beautiful 10 pound 6 ounce baby boy who has a gorgeous red port wine stain on his hand (it looks like he played in kool-aid!). Was this the reason for his poly? We might never know.
Hope this helps.