Nicolas V. Simon

Individual growth curve standards in twins: Prediction of third-trimester growth and birth characteristics

The ability of Rossavik growth models, determined from measurements obtained before 24 weeks, to predict third-trimester growth and birth characteristics in normally growing twins has been investigated. Third-trimester values for head circumference, abdominal circumference, and femur diaphysis length were predicted with an accuracy of +/- 6% to 9% (95% to 98% of percent deviations). For thigh circumference and estimated weight, the comparable values were +/- 15% and +/- 16%, respectively. The head circumference at birth was predicted without bias; the random error was approximately +/- 5% (94% of percent differences). Weight, abdominal circumference, and thigh circumference were systematically overestimated (3.1%, 14.9%, and 11.3%, respectively) as a result of differences in prenatal and postnatal measurement procedures. After correction for systematic errors, these parameters could be predicted with random errors of -11.5% to 7.2% (weight), -12.8% to 5.4% (abdominal circumference), and -15.3% to 10.0% (thigh circumference). Growth Potential Realization Index values were found to have means of approximately 100% and ranges from 91% to 118%. These results are similar to those for singletons and indicate that individual assessment of growth in twins can be carried out with the same methods used for singletons.

Treatment of fetal supraventricular tachycardia with flecainide acetate after digoxin failure

Transplacentally administered digoxin is the drug of choice for the treatment of fetal supraventricular tachycardia. We describe a case of fetal supraventricular tachycardia associated with fetal hydrops that did not respond to digoxin treatment because of a lack of transplacental passage. In contrast, flecainide acetate crossed the placenta and cured the fetus. The clinical implications of this new treatment are discussed.

Studies on the growth-inhibiting property of amniotic fluids from two United States population groups.

This study attempted to determine if lack of antimicrobial activity in amniotic fluid is the reason United States blacks have more amniotic fluid bacterial infection than whites. No significant interracial differences were found in a study of 111 fluids from whites and 56 fluids from blacks. It has been claimed that the phosphate:zinc ratio in amniotic fluid is an accurate predictor of antimicrobial activity. The present study found this often to be untrue. Amniotic fluids that lacked antimicrobial activity gained such activity when zinc was added, but the in vitro zinc levels required were usually higher than observed physiologic concentrations. Previous studies have claimed that antimicrobial activity first appears in the amniotic fluid in the third trimester of gestation. We found such activity in the majority of fluids by the end of the first trimester, with a Staphylococcus aureus indicator; in contrast, with Escherichia coli and Streptococcus agalactiae as test organisms, greater inhibition was observed after 35 weeks.