Below is an instruction that describes a task. Write a response that appropriately completes the request. ### Instruction: Failure to thrive, possible causes to consider?Kiddo born last week of October 2022 at 39+1 (vaginal birth via induction) weighed 5lb 9 oz, looked quite small for the weight and had short, withered looking legs and a disproportionately small butt. At 5 months, weighted 12lb 5.5 oz. Has consistently been 0.5 percentile although recently scraped up tp 0.6. Legs have filled out and lengthened, butt is more or a normal size. kid has been hitting motor and social developmentsl markers very well, but is deemed failure to thrive. Baby is breastfed, milk supply not the problem. Bottle is offered after every nursing, but not forced by parents, as this leads to vomiting.Mother 42 at delivery, pregnancy the result of IVF with a PG tested embryo. IUGR was first diagnosed in the second trimester, amnio and weekly placenta monitoring followed. Amnio revealed a microdeletion of unknown significance on 6p which was at length deemed unlikely to be the cause of anything by maternal fetal medicine genetic specialists - even before testing revealed the microdeletion to be inherited from the father, who has no disadvantages or disability.Mother contracted Covid in the early/mid second trimester, was fully vaccinated and fully recovered in 1-2 weeks. Mother struggled to eat during the pregnancy and after birth weighed 10lb less than she had when the embryo was transferred. Mother took diclegis, tums and omeprazole daily throughout the pregnancy to manage nausea. Mother had a UTI from week 10-20 that took 3 treatments to clear. Both the covid and the nausea were dismissed as a cause of the IUGR by both the OB and the Maternal Fetal Medicine Doctors.Currently waiting on a referral to genetics at a local hospital to investigate the possibility of skeletal dysplasia. The only visible symptom for dwarfism is a very, very slightly protruding forehead. Head circumference has always been in the 50th perventile despite the little body.So.What could be causing this, or have caused it? The final opinion from the Doctors at the MFM clinic was "Hes just a little guy." For the sake of assuaging parental guilt, it would be good to know how likely it is that the inability to eat could have contributed to the problem.. ### Response: If the child is growing along a percentile curve and staying on that curve, technically this is "failure to thrive" (also known as growth faltering) but my concern is generally low. If they're gaining weight at a lower amount than they should be or crossing percentile lines, that's where we really get concerned. How does his weight for length curve look?.