Guide to PKU - Mead Johnson Nutrition

Maternal PKU:When Your Daughter IsReady To Have ChildrenIn the past, children with PKUwere usually permitted to discontinuetreatment (and have elevatedblood phenylalanine levels) beforeadolescence. However, severalstudies have shown that childrenwho discontinue treatment or havehigh Phe levels have more difficultieswith thinking processes andmath skills. Other studies havefound that elevated blood phenylalaninelevels in older patientswere associated with behavior andlearning problems which werereversed when the patientsreturned to more restricted diets.For these reasons, most clinics arenow recommending that personswith PKU remain on the diet forlife. This “diet for life,” whichmeans good Phe levels for life, isa strong recommendation—discontinuing treatment is notadvised at any age.As they begin their menstrualcycles, girls with PKU shouldunderstand the effect PKU canhave on developing babies.High blood levels of phenylalanineare very damaging to adeveloping fetus.Researchers have found that, asthe mother’s blood phenylalaninelevels increase, her chance ofhaving a baby with an abnormallysmall head and mental retardationalso increased. Incidence of lowbirth weight and congenitalheart disease appears to increasemarkedly when serum phenylalaninelevels are consistently abovethe “good level.” In women whohave not stayed on the diet, it isnecessary to reinstate dietarytherapy before conception. Theprognosis for having a normalchild is better, but it is criticalthat diet therapy begins beforeconception. The fetus is verysensitive to high levels ofphenylalanine. The early monthsof pregnancy are believed to bethe most crucial for normaldevelopment.For these reasons, it’s veryimportant that women withPKU follow their phenylalanine-restricted diet before conceivingand throughout pregnancy.Because it’s so difficult to go backto the diet after being off it, it isespecially important that womencontrol their blood phenylalaninefor a lifetime.15