Birth weight of Italian infants of 30 weeks' gestation or less

Medical statistics in obstetrics and gynaecology

Statistics are involved in many aspects of obstetrics and gynaecology: measurement and diagnosis, randomized trials, epidemiology, basic biological research, and the compilation of national data. Obstetrics and gynaecology has stimulated advances in statistics, particularly in the construction of centile charts and the development of meta-analysis. This account draws largely on the author's own experience of research in obstetrics and gynaecology.

Postnatal weight velocity patterns in very low birthweight infants

The care of very-low-birth-weight infants has improved over the years with continuing changes in medical and nutritional management. In view of these changes, there is a need to study the pattern of postnatal weight gain. Postnatal weight gain patterns of 32 very-low-birth-weight infants were examined during the first two months of life. Their mean gestational age was 29.5 +/- 2.3 weeks and mean birth weight was 1255 +/- 258 grams. The babies were weighed daily and weight changes were expressed in gram/day. All data were accurately recorded. When mean weight gain profiles were obtained by computing increments at 1, 3, 7 and 14 day intervals, the babies weight gain showed a non-linear pulsatile pattern which did not change even after full enteral nutrition had been established. This study demonstrates that weight velocity profile in very-low-birth-weight infants is not linear as expected from available standard curves and these data might therefore be considered while monitoring the adequacy of the increments of the weight gain of the individual subjects.

[Fetal growth in premature infants in Haute-Normandie]

BACKGROUND

Fetal growth standards of preterm infants are different from one study to another, especially for extremely preterm babies.

POPULATION AND METHODS

Between 1976 and 1990, a cross-sectional study of the resulting intrauterine growth of premature newborns from Haute-Normandie (France) was conducted by collecting data of the compulsory health certificate set up in the first week after birth. In spite of exclusions, curves for obstetrical terms ranging from 28 to 36 weeks of gestational age were settled. Equivalents of 8,042 birth weights, 7,792 statures, 8,041 head circumferences and 6,737 ponderal index were used.

RESULTS

Comparing our results with those published in the literature, we observed short differences for mean or middle values: from less than 170 to more than 180 g for weight, from less than 1 to more than 2.6 cm for stature and from less than 1 to more than 1.9 cm for head circumference.

CONCLUSION

The selected normal lower threshold for each parameter and the varieties of fetal growth inadequacy are under discussion.

Pulsatile weight increases in very low birthweight babies appropriate for gestational age

The weight increment profiles of 20 low birthweight babies measured during the first two months of extrauterine life were analysed. The babies were weighed daily, and the weight profiles showed minor irregularities when compared with an interpolated linear trend. When increments were plotted at two week intervals a linear increase in weight velocity was seen, but when increments were computed every three days, the velocity profile was non-linear and pulsatile. All cases studied showed regular pulsatile patterns of weight velocity during the first two months of life. A mean profile of the 20 babies permitted estimation of the periodicity of the pulsing: the cycle alternated every nine to 11 days. A non-linear pattern was found in the published series of unsmoothed data that have been widely adopted as standards for growth in low birthweight babies.