Women diagnosed with Phenylketonuria (PKU) face specific risks during pregnancy. For a healthy gestational period, strict adherence to a special dietary treatment before and throughout pregnancy is vital. If the diet is not followed, phenylalanine levels in the mother's blood can rise dangerously. This can cause serious harm to the developing fetus, increase the risk of miscarriage, and lead to various health problems in the baby after birth. Possible health problems observed in babies born from pregnancies with uncontrolled phenylalanine levels include:

* Low birth weight
* Developmental delay
* Facial anomalies
* Microcephaly (abnormally small head)
* Congenital heart defects and other cardiac issues
* Intellectual disability
* Behavioral problems