I  have found only two common denominators: lots of IV Fluids in labor and
pitocin. In CNM a table on the effects of medication in labor says pitocin
can lead to fluid retention (citing the package insert). THe picture gets
really jumbled because if the mom has an epidural then she is usually
overhydrated before the epidural is started (Our Anest. Department says mom
has to have 2 liters of IV fluid before they will start the epidural) The
epidural slows labor and viola--out comes the pitocin more IV  and ... (you
get the picture 0)

I recently worked with a mom whose areola were so edematous it looked like
orange peel. (I posted about this mom and the use of an inverted nipple
shield) 12 days post partum she finally got rid of the excess fluid and lost
18 pounds overnight. If I remember correctly, a gallon of water weights 8.2
pounds so her 18 lb loss is  over two gallons of fluid in less than 8 hours!
 Her baby is finally latching on and nursing well without the shield. (not to
mention how please she was to be able to put on her shoes)
What worked for her was a combination of fresh watermelon and kelp pills both
have diuretic properties.
Marie Davis