Fetal catecholamine release in response to labor and delivery.

Umbilical arterial plasma norepinephrine and epinephrine were measured using a sensitive, specific radioenzymatic assay. Plasma catecholamines were correlated with umbilical arterial blood gases, durations of the first and second stages of labor, duration of rupture of the membranes, fetal heart rate tracings, and fetal sex. Significant correlations were observed for plasma norepinephrine versus fetal pH and PO2 and plasma epinephrine versus pH but not PO2. The majority of the fetal heart rate tracings demonstrated either a normal baseline or mild variable decelerations. The plasma catecholamines and blood gases were similar in these 2 groups. Significant elevations of both plasma catecholamines were observed with those tracings commonly associated with fetal distress; however, the number of infants was small. No sex differences were observed in plasma norepinephrine or epinephrine or in responsiveness. The results suggest that the human fetus at term responds to acidosis and hypoxia with a graded catecholamine release. This may be an important adaptive mechanism.

Nonstress and contraction stress fetal heart rate monitoring. A randomized trial to determine which is the faster primary test.

Antepartum fetal heart rate monitoring can be performed with either the nonstress or contraction stress method. The recent introduction of nipple stimulation as a means of achieving uterine contraction has simplified performance of contraction stress tests and raises the possibility that that test may be a more rapid approach to antepartum fetal heart rate testing than the nonstress test. In order to investigate the time taken to achieve a satisfactory end point of fetal heart rate monitoring, 186 women were randomized to either "intention to perform nonstress test" or "intention to perform nipple stimulation contraction stress test." Neither approach was found to be significantly faster than the other. One-third of all completed contraction stress tests were classified as equivocal and required further investigation or management. The nipple stimulation contraction stress test was not found to be a more rapid approach to antepartum fetal heart rate monitoring than the nonstress test.

Effect of vibratory acoustic stimulation on the duration of fetal heart rate monitoring tests.

The ability of vibratory acoustic stimulation to shorten the duration of antepartum fetal heart rate monitoring was investigated by a randomized controlled trial. Vibratory acoustic stimulation did not shorten the overall duration of testing. This failure to improve the performance of antepartum monitoring appeared to result from prolonged accelerations, which complicated one third of the tests in which vibratory acoustic stimulation was employed. Further investigation is warranted using less profound methods of fetal stimulation.

Contraction stress fetal heart rate monitoring at preterm gestational ages.

The evaluation of fetal well-being by fetal heart rate monitoring at preterm gestational ages remains a difficult and important area for investigation. While the nonstress test has achieved widespread usage, a role for the contraction stress test remains uncertain. This study describes the outcome of 113 contraction stress tests which were performed for persistent fetal heart rate nonreactivity in 78 pregnancies of less than 37 completed weeks' gestation. There were no fetal deaths and no obstetric complications which could be attributed to these tests. The finding of a negative contraction stress test provided reassurance which facilitated significant prolongation of pregnancy. Contraction stress test appear to be a safe and effective method of investigating further the clinical dilemma of persistent fetal heart rate nonreactivity in high risk pregnancies at preterm gestational ages.

A randomised controlled trial of dietary energy restriction in the management of obese women with gestational diabetes.

A randomised controlled trial was designed to determine the effect of moderate 30% maternal dietary energy restriction on the requirement for maternal insulin therapy and the incidence of macrosomia in gestational diabetes. Although the control group restricted their intake to a level similar to that of the intervention group (6,845 kiloJoules (kJ) versus 6,579 kJ), the resulting cohort could not identify any adverse effect of energy restriction in pregnancy. Energy restriction did not alter the frequency of insulin therapy (17.5% in the intervention group and 16.9% in the control group). Mean birthweight (3,461 g in the intervention group and 3,267 g in the control group) was not affected. There was a trend in the intervention group towards later gestational age at commencement of insulin therapy (33 weeks versus 31 weeks) and lower maximum daily insulin dose (23 units versus 60 units) which did not reach statistical significance. Energy restriction did not cause an increase in ketonemia.