Maternal dietary substrates and human fetal biophysical activity. I. The effects of tryptophan and glucose on fetal breathing movements

Lawrence D. Devoe, Ramon A. Castillo, Nancy S. Searle, John R. Searle

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To study the effects of l-tryptophan and glucose on fetal breathing activity, we examined 40 women with normal term pregnancies, randomly assigned to four equal groups who either continued fasting (group C), received 1 gm of oral tryptophan (group T), received 100 gm of oral glucose (group G), or received both substrates (group T + G). Studies lasted 210 minutes, during which fetal breathing movements were observed with real-time ultrasonography and entered and analyzed for incidence, rate, and variability on a microcomputer. Plasma glucose and tryptophan levels were determined every 30 minutes. The incidence of fetal breathing movements declined in group C and rose significantly in the other groups. Breathing rates were unchanged in groups C and T but rose significantly in groups G and T + G during peak breathing intervals. Breath interval variability did not change significantly in any study group. Maternal administration of tryptophan is associated with an alteration in fetal breathing activity but to a lesser degree than that observed after maternal glucose loading.

Original languageEnglish (US)
Pages (from-to)135-139
Number of pages5
JournalAmerican journal of obstetrics and gynecology
Issue number1
Publication statusPublished - Jul 1986



  • Tryptophan
  • fetal breathing movements
  • glucose

ASJC Scopus subject areas

  • Obstetrics and Gynecology

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