I have not seen any studies done on the contraceptive effect of breastmilk pumping as opposed to breastfeeding. I have noted during many years of experience working on an NICU, that even mothers, who are pumping very frequently and producing large quantities of breastmilk for their preterm babies, tend to start ovulating/menstruating again within the first three to four months post birth. Carol Bartle RN/RM/IBCLC Christchurch New Zealand. *********************************************** The LACTNET mailing list is powered by L-Soft's renowned LISTSERV(R) list management software together with L-Soft's LSMTP(TM) mailer for lightning fast mail delivery. For more information, go to: http://www.lsoft.com/LISTSERV-powered.html