D. -
Unless your son is underweight there is no reason you need to supplement. No, having to use formula is not the worst thing in the world, however, it seems some do not understand how it crushes a mother to feel that she cannot provide enough for her child. Take Fenugreek (found in most health food stores), you can drink the Mother's milk tea but you have to drink alot of it to have any effect. Drink alot of water, eat oatmeal. Nurse your son ALOT. It is all supply and demand. If you nurse more, you will make more. If you can't get him to eat, them pump inbetween. If you take a "nursing vacation" for several days, spend alot of time in bed (and skin to skin contact is good to encourage him to nurse as well) and just nurse as often as possible. If that doesn't work, there are some drugs that are effective at increasing milk supply. You have done so great for 9 1/2 months, it's really a shame to give up now....and if you start supplementing, your milk supply will decrease even more because he won't nurse as often cause formula is harder to digest.
Most doctors have no clue what they are talking about but yet feel the neeed to dole out advice regarding breastfeeding. Their training is very minimal and their growth charts are all based on formula fed babies, who at your son's age would be heavier. Breast fed babies gain ALOT of weight in the beginning. Then as they start taking more reg food and less breastmilk and become more active between 9-12 months they thin out more. Breastmilk has more calories and fat than table food and some of your breastmilk is being replaced. Then the docs start to say your child is "falling off the growth chart" because he started off being 95th percentile and now he is in the 30s or 40s. It is very important to understand that those percents are all based on formula fed babies who grow at different rates. Every child is different, and as long as they look healthy and are not dangerously underweight there is no reason for concern. I have finally found a doctor who knows what they are talking about when it comes to breastfeeding...this is Homefirst clinic and they have many locations in Chicago land.
Unless your son is seriously underweight, I wouldn't even consider it. Say "yes doctor" and work to increase your supply. And suddenly between 18 months and 2 years he will be an incredibly healthy height and weight. http://www.lalecheleague.org/llleaderweb/LV/LVAugSep99p75...
Please talk to a lactation consultant or if you can't pay for one, call up a LLL leader ( you can get leader info off their website). They will be more than happy to help you.
If you want any more info please check out this site http://www.kellymom.com/bf/supply/low-supply.html. If you are pumping, please be aware that just because you may not be able to pump alot doesn't mean you aren't producing enough. A pump is not as efficient as a baby.
A lot of breastfeeding experts are also saying now that it is ok to give the baby cow's milk if they are over 6 months, as long as it is only a small amount of the total milk they take in. http://www.kellymom.com/newman/10bf_and_other_foods.html#...
Good luck and I really hope everything works out for you. It is really a shame that more breastfeeding mothers don't educate themselves more on these things because they could continue to have breastfed.