Attenuation of sympathoadrenal function during delivery in the fetus of a diabetic mother

Abstract

Objective

We compared the association between cord arterial catecholamine levels and fetal oxygenation in newborns of mothers with diabetes mellitus to those of nondiabetic pregnancies.

Methods

Cord blood obtained at delivery in 25 term appropriate-for-gestational age newborns of women with diabetes and 27 nondiabetic controls were assayed for norepinephrine, epinephrine, insulin, glucose, and blood gases.

Results

There was no statistical difference in parity, birth weight, gestational age, delivery mode, use of epidural analgesia, or frequency of low 1-min Apgar scores between the groups. The pO₂ and frequency of cord arterial pH < 7.20 were also similar. Diabetic pregnancies had somewhat higher fetal glucose and substantially higher insulin levels than controls. Regression analysis using cord arterial pH to reflect oxygenation revealed significant inverse relationships between cord artery pH and ln norepinephrine (Prob > F = .001) and ln epinephrine (Prob > F = .019) in controls. In newborns of women with diabetes, however, neither relationship was significant.

Conclusion

The expected surge in catecholamines associated with diminished oxygenation was attenuated in fetuses of diabetic mothers. This suggests the possibility that fetal exposure to hyperglycemia or other metabolic derangements in pregnant diabetics might compromise the fetal ability to adapt to changes in oxygenation, and might thereby contribute to the risk of fetal death.

Keywords:

• Catecholamines
• diabetes mellitus
• epinephrine
• fetal death
• norepinephrine
• pregnancy

Acknowledgments

We are grateful for the superb technical assistance of Ms. Joan Deutsch (deceased) with the biochemical assays.

Disclosure statement

No potential conflict of interest was reported by the authors.