Hi Bex Congratulations on your pregnancy. I have no medical advice to provide but have had 2 successful pregnancies whilst taking clexane and breastfed both, 1st for 6 weeks, 2nd for 6 months. I was advised there was no reason why I should not feed whilst on clexane. I definately recommend you ask about having clexane for 6 weeks rather than warfarin. I was hospitalised at 6 weeks after my first birth and I can assure you expressing for so long is not an option. I was in for a week, unable to feed my expressed milk due to my medication, and my baby never really took to the breast after that. And trying to keep your supply adequate to feed a hungry baby is very hard work. Good luck hun. x