This is a new one to me but I can relate it to the experience of a friend....
 she had such intense afterbirth pains that for several days postpartum she
vomited with every nursing.  She could feel the cramps though, and we always
assumed the pain ---> vomiting, not the cramps per se.  If this mom got PG on
OCs then her hormonal system is a bit different from most folks.  Will be
interested to hear more on this.
Mary Renard