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SUMMARY Both the age of the infant and the birthweight in relation to age are relevant factors in studying prenatal and neonatal physiology and in evaluating immediate and future clinical risks to the fetus and the newborn. Since the true age of the infant (the time‐span from conception) is not available, the first day of the last menstrual period is commonly used as the time reference. In many cases, however, there is doubt as to the accuracy of this reference day, necessitating other criteria to indicate the duration of fetal development or of the postmenstrual age of the newborn. The authors discuss the use of pre‐ and postnatal evaluations of the developmental changes in various organ systems‐by physical measurement, observation, physiological registrations and biochemical analysis ‐ for the estimation of the postmenstrual age. They use the following criteria: Does the observable phenomenon change suddenly from absent to present at a particular postmenstrual age? Does the phenomenon remain unaltered in sick children? Is the method relatively easy and reliable? Is the technique without risk for the fetus, the mother and the newborn? At present, a combination of parameters, serially measured, on the developing nervous system and the developmental changes of the skin seem to be most helpful in pre‐ and postnatal life, and the authors report that the optimal accuracy obtainable so far still has a range of plus or minus 2–3 weeks. The reasons for this wide range are discussed. RÉSUMÉ Estimation de & lcar;âge post‐menstruel: vue d'ensemble L'âge de l'enfant et le poids de naissance en fonction de l'âge sont tout deux des facteurs importants dans l'étude de la physiologie prénatale et néo‐natale, dans l'évaluation clinique des risques immédiats et futurs du foetus et du nouveau‐né. Puisque l'âge vrai de l'enfant (durée depuis la conception) ne peut être connu, le premier jour des derniéres régies est pris généralement comme référence. Dans de nombreux cas cependant, on peut douter de la précision de cette référence et d'autres critéres sont néces‐saires pour indiquer la durée du développement foetal ou l'âge post‐menstruel du nouveau‐né. Les auteurs discutent l'emploi de mesures pré et post‐natales de modifications lieés au développement au niveau de certains organes pour la détermination de l'âge post‐menstruel (par mesure physique, observations, enregistrement physiologique et analyse biochimique). lis utilisent les critéres suivants: Le phénoméne observé“passe‐t‐il de l'absence à la présence brusquement à un âge post‐menstruel particulier? Ce phénoméne persiste‐t‐il chez les enfants malades? La méthode est‐elle suffisamment facile et fidéle? La technique est‐elle sans risque pour le foetus, la mére et le nouveau‐né? A l'heure actuelle, une combinaison de paramétres, déterminés sur des séries, au niveau du développement du systéme nerveux et des modifications progressives de la peau semble être la plus utile durant la vie pré ou post‐natale; les auteurs précisent que la précision optimale atteinte jusqu'a ce jour ...
SUMMARY Both the age of the infant and the birthweight in relation to age are relevant factors in studying prenatal and neonatal physiology and in evaluating immediate and future clinical risks to the fetus and the newborn. Since the true age of the infant (the time‐span from conception) is not available, the first day of the last menstrual period is commonly used as the time reference. In many cases, however, there is doubt as to the accuracy of this reference day, necessitating other criteria to indicate the duration of fetal development or of the postmenstrual age of the newborn. The authors discuss the use of pre‐ and postnatal evaluations of the developmental changes in various organ systems‐by physical measurement, observation, physiological registrations and biochemical analysis ‐ for the estimation of the postmenstrual age. They use the following criteria: Does the observable phenomenon change suddenly from absent to present at a particular postmenstrual age? Does the phenomenon remain unaltered in sick children? Is the method relatively easy and reliable? Is the technique without risk for the fetus, the mother and the newborn? At present, a combination of parameters, serially measured, on the developing nervous system and the developmental changes of the skin seem to be most helpful in pre‐ and postnatal life, and the authors report that the optimal accuracy obtainable so far still has a range of plus or minus 2–3 weeks. The reasons for this wide range are discussed. RÉSUMÉ Estimation de & lcar;âge post‐menstruel: vue d'ensemble L'âge de l'enfant et le poids de naissance en fonction de l'âge sont tout deux des facteurs importants dans l'étude de la physiologie prénatale et néo‐natale, dans l'évaluation clinique des risques immédiats et futurs du foetus et du nouveau‐né. Puisque l'âge vrai de l'enfant (durée depuis la conception) ne peut être connu, le premier jour des derniéres régies est pris généralement comme référence. Dans de nombreux cas cependant, on peut douter de la précision de cette référence et d'autres critéres sont néces‐saires pour indiquer la durée du développement foetal ou l'âge post‐menstruel du nouveau‐né. Les auteurs discutent l'emploi de mesures pré et post‐natales de modifications lieés au développement au niveau de certains organes pour la détermination de l'âge post‐menstruel (par mesure physique, observations, enregistrement physiologique et analyse biochimique). lis utilisent les critéres suivants: Le phénoméne observé“passe‐t‐il de l'absence à la présence brusquement à un âge post‐menstruel particulier? Ce phénoméne persiste‐t‐il chez les enfants malades? La méthode est‐elle suffisamment facile et fidéle? La technique est‐elle sans risque pour le foetus, la mére et le nouveau‐né? A l'heure actuelle, une combinaison de paramétres, déterminés sur des séries, au niveau du développement du systéme nerveux et des modifications progressives de la peau semble être la plus utile durant la vie pré ou post‐natale; les auteurs précisent que la précision optimale atteinte jusqu'a ce jour ...
Abstract. Fetal systolic time intervals (FSTI) were derived from the externally recorded electrocardiogram and phonocardiogram in 74 women during late pregnancy. The FSTI of the first 43 patients were recorded as a control. In the others FSTI were registered before and after intravenous injection of atropine to the mother to increase the range of fetal heart rate. Two patients in the atropine group were excluded. Correlation was found between the duration of the heart cycle (R‐R interval) and the mechanical systole (S1‐S2 interval) before and after atropine. The amplitude of the initial part of the first heart sound (S1a) increased after atropine, when postatropine tachycardia evidenced significant placental transfer of the drug. After atropine some fetuses showed initial bradycardia or bradycardia without following tachycardia. In such periods of bradycardia S1a amplitude was reduced. During the initial period of postatropine tachycardia short periods of constant R‐R interval combined with varying S1a amplitude and S1‐S2 interval occurred. A close correlation was then present between S1a amplitude and S1‐S2 interval. The time from electrical to mechanical start of ventricular systole was measured as the R‐S1 interval; it did not vary with heart rate in the control group or in the atropine group before atropine was given. Atropine shortened the R‐S1 interval; no correlation was found between shortening and tachycardia. It is concluded that in the fetus, changes of FSTI can be observed from the externally recorded electrocardiogram and phonocardiogram. Signs of peripheral circulatory change after atropine were not found. The changes observed after atropinization can be explained as a reduction of vagal tonic inhibition of cardiac chronotropism and inotropism. Atropine also may cause a decrease of mitral valve flow.
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