Jonathan,
The mothers in the Rigard study were given pethidine (Demerol or meperdine).
 I think it was given I.M. or I.V.  It is my understanding that dosages are
much smaller and systemic absorption much less with epidural administration.
 I am all for natural birth, but if moms need or want medication, I would
like to promote that which interferes the least. Thanks for taking the time
to respond, and please correct me if I am wrong.  Bonnie Jones, RN, ICCE,
IBCLC