Maternal phenylketonuria collaborative study, obstetric aspects and outcome: The first 6 years

Reuben Matalon, Felix de la Cruz, Colleen Azen, Catherine A. Walla

Research output: Contribution to journalArticlepeer-review

61 Scopus citations


Objective: The purpose of this study was to evaluate the efficacy of a phenylalanine-restricted diet in reducing fetal morbidity associated with maternal hyperphenylalaninemia in women of childbearing age with blood phenylalanine levels >240 μmol/L (>4 mg/dl) on an unrestricted diet. Study Design: Two hundred thirteen pregnant women with hyperphenylalaninemia that resulted in 134 live births have been enrolled in the study. Outcome measures were subject to the χ2 test, Fisher exact test, analysis of variance, t test, or Wilcoxon nonparametric test for analysis. Results: Optimal fetal outcome appeared to occur when blood phenylalanine levels <600 μmol/L (<10 mg/dl) were achieved by 8 to 10 weeks' gestation and maintained throughout pregnancy (trimester averages of ≤360 μmol/L (≤6 mg/dl)). Initiation of dietary therapy during the third trimester of pregnancy appears to have little beneficial effect on the fetus. Conclusions: Preconceptual counseling and early entrance into a prenatal care program is essential in achieving optimal fetal outcome in women with hyperphenylalaninemia.

Original languageEnglish (US)
Pages (from-to)1150-1162
Number of pages13
JournalAmerican journal of obstetrics and gynecology
Issue number4
StatePublished - 1992
Externally publishedYes


  • Maternal phenylketonuria
  • congenital defects
  • dietary therapy
  • fetus
  • mental retardation

ASJC Scopus subject areas

  • Obstetrics and Gynecology


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