My son (child #2) just had his 4 month check up today. At birth, he was in the 80 something percentile (don't remember the exact #) for weight. At his two month checkup, he was in the 65th percentile for weight. Today, at his four month, he is down to the 33rd percentile. I was really surprised because I hadn't noticed anything that would lead me to be concerned about his intake or weight gain. This is my second child. With my first, I'm pretty sure I had oversupply issues and she never had any issue gaining weight.
The pediatrician thought the issue could be low supply or it could be something else like acid reflux (he still spits up a good deal, but has never been on meds and never seems to be upset by the spit up).
Before I go crazy trying to increase my supply, I first want to know if that is really the issue. Is there a way that I can "measure" my supply? My pediatrician recommended that I pump first thing in the morning and that if I got less than 3-4 oz, that would show I had low supply. However, I'm wary of any pediatrician's lactation advice because it often seems to contradict what I find on La Leche League forums. Any better way to tell if low supply is my problem? Like I said, I'm really surprised by the lack of weight gain because I thought oversupply was my problem, not low supply.
A few details... my son feeds every 2 hours or so during the day, usually only one breast per feeding. Sometimes spits up a fair amount soon after eating. He seems content after eating. He was sleeping a 4-5 hr stretch at night but about two weeks ago, he started waking every 1-3 hours again. I feed him almost every time he wakes (unless the paci puts him back to sleep right away). I've always fed on demand and breastfeed exclusively. Early on, he was a very fussy nurser and commenters on this forum thought that he might also be experiencing oversupply issues but that all seemed to resolve itself around 2.5 months.