The Estimation of the Postmenstrual Age: a Comprehensive Review

Abstract

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 ...

Assessment of Gestational Age: Modification of a Simplified Method

“…The value of such a combination has been reported previously (Casaer andAkiyama 1970, Dubowitz et al 1970). External features assess maturational skin changes, and MAC the growth of fat and muscle mass.…”

“…improves the reliability of maturity dem termination (Casaer andAkiyama 1970, Dubowitz et al 1970). Indeed, the corm relation of total maturity scores of the 2 Dubowitz system with gestational age was s improved when combined with head 9 2 circumference measurements (Finnstrom 1972 age was within two weeks of that by dates, it was considered accurate (Ballard et af.…”

A Polygraphic Study of Bioelectrical Brain Maturation In Preterm Infants

“…Thus the assessment of 'bioelectrical age' can be of use for infants whose expected date of delivery is uncertain. The accuracy of estimation by this method is within about the same range as other clinical methods used for preterm infants when data on the length of gestation are lacking (Casaer and Akiyama 1970). Determination of 'bioelectrical age' might also prove useful for infants with a known post-menstrual age but who are at risk with regard to normal development.…”

A Simplified Method of Estimating Gestational Age in an African Population

“…External and neurological features were included in the model to ensure reliability. This is improved when methods which assess different aspects of development and which show good individual correlation with gestational age are combined (Casaer and Akiyama 1970, Dubowitz et af. 1970, Finnstrom 1972.…”