Polyhydramnios means you have too much amniotic fluid in the womb (uterus). Most cases of polyhydramnios are mild or moderate. Polyhydramnios tends to make the following pregnancy symptoms worse: indigestion, heartburn, constipation, swollen legs, varicose veins and stretch marks. The labour is likely to be normal. However, the extra fluid puts it at higher risk of certain complications so it is recommended to give birth on an obstetric-led labour ward. The weight of the baby and the extra fluid may cause early labour. The extra fluid in the womb makes it difficult for the baby to settle his head down into the pelvis. So if the umbilical cord is pulled down into the vagina and in front of his head, the gynae may recommend an emergency caesarean. The placenta may come away early if the womb suddenly shrinks as the amniotic fluid is released. Here is an article that may help better your understanding so that you can understand your friend's situation clearer: http://www.babycentre.co.uk/a551936/polyhydramnios
Usually, expectant mothers with polyhydramnios will be advised to rest and to avoid activities that make them breathless. Sometimes, the doctor might prescribe a drug to reduce the amount of urine the baby passes in order to not add on to the existing fluids. If you have severe polyhydramnios, you may need some of the amniotic fluid to be drained off to reduce the risk of premature labour. This procedure can be risky, sometimes causing infection, bleeding and complications with the placenta. Best treatment in most cases is for expectant moms to take early maternity leave and rest as much as possible. Not to worry though, the majority of moms with polyhydramnios give birth to perfectly healthy babies.