A woman with phenylketonuria can have healthy children provided a number of steps are taken before and during pregnancy. Failure to adhere to the steps increases the risk of serious malformations in the children.


Molecular weight of phenylalanine: 165.2 g


Risk factors associated with congenital defects in children of a mother with phenylketonuria:

(1) poorly controlled or uncontrolled phenylalanine blood levels in the blood before or during the pregnancy, typically with blood levels >= 600 micromoles/L

(2) fluctuations in phenylalanine blood levels

(3) poor weight gain during the pregnancy

(4) poor dietary vitamin and protein intake during the first trimester


Steps to minimize congenital defects in children of mothers with phenylketonuria:

(1) Start control of blood phenylalanine levels prior to conception.

(2) Maintain control of blood phenylalanine levels throughout pregnancy.

(3) Target blood phenylalanine levels to 120-360 micromoles/L.

(4) Avoid fluctuations in the blood phenylalanine levels.

(5) Maternal weight gain should be carefully monitored.

(6) The diet should provide adequate intake of energy, protein, minerals and vitamins, especially during the first trimester.


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