Hi Spitting up is quite common in early infancy. Since it results in frequent aspiration, please discuss with your Pediatrician regarding treatment with Medications like Domperidone, Proton Pump Inhibitors etc. The precautionary measures may sound simple. But they will help a lot. - Side lying posture will be better while she sleeps. Make her lie to her left side so that left side of the body faces down. This reduces the risk of aspiration too. - Head end elevation. - Do not make her lie immediately after feeds. She has to be kept upright atleast for half an hour after feeds. - Do not rock her after feeds - Make sure that you burp her after each feeds - Do not over feed her. Instead feed her in small quantities but frequently. - The idea behind thickening of formula is thick feeds will not come up easily from the stomach as does milk alone. If you are scared of this, you need not do it. - Try to put her on exclusive breast feeding till she completes 6 months of age. Since she has had frequent aspiration episodes, you must discuss with your Pediatrician regarding medications. This will help. Hope my answer helps you. Wish your little one good health.