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Biomedical subjects

M Ounsted

Publications and source records attributed to M Ounsted.

At least 19 recordsLinked to original sources

Small-for-dates babies, gestational age, and developmental ability at 7 years.

One hundred sixteen small-for-dates (SFD) children, whose progress had been monitored prospectively from birth, completed a comprehensive developmental assessment at age 7 years. There was an inverse relationship between their developmental scores at 7 years and gestational age at birth. Further analyses showed that the negative associations were stronger when biological factors commonly associated with the birth of SFD babies were absent. SFD babies are often delivered electively before term because of their increased risks of intrauterine death. The infant's ability to withstand the perinatal metamorphosis is usually assured, prior to intervention. Our findings indicate that, among SFD children in general, prolongation of pregnancy beyond about 36 weeks is not associated with an improved long-term prognosis. When pathological factors are operant, delivery before term may enhance the chances of these babies achieving their full developmental potential in later childhood.

Child

Neurological development of small-for-gestational age babies during the first year of life.

137 small-for-gestational age (SGA) infants were examined in the neonatal period and at 2, 6 and 12 months. At each age a structured assessment was used for which a score denoting neurological maturation could be given. The SGA infants were significantly retarded compared with average-for-gestational age (AGA) infants from 2 months onwards. Within the SGA group the mean scores for boys, those who were first-born, breast-fed and/or born to mothers who smoked during pregnancy were in each case significantly higher than the rest at 6 and 12 months. Maternal smoking influenced all aspects of development at 12 months; whereas sex and method of infant feeding mainly affected the motor items, and birth order only those that were socially oriented. Positive associations were found between changes in somatic measures and changes in neurological scores from birth through to 6 months. Infants who grew faster also matured faster during this period of time, and vice versa. Positive correlations were found between size and scores at 2 and 6 months, but not at 12 months.

Age Factors

Head circumference and developmental ability at the age of seven years.

Data on 365 children who had been small (SGA) average (AGA) or large (LGA) for gestational age at birth were analysed at the age of seven years. Significant positive correlations were found between head circumference and developmental scores in the SGA and LGA groups. These were mainly due to associations between relatively small heads and low scores. Familial factors, social class and sex affect both head circumference and developmental ability at this age. Their influences on these two parameters differ in degree; and in the case of sex, in direction. When account was taken of these other factors the contribution of birth-weight group to the variance in head circumference remained high; but its contribution to developmental scores was reduced.

Birth Weight

A longitudinal study of tooth emergence and somatic growth in 697 children from birth to three years.

The study was on three groups of children who had been small (SGA), average (AGA) or large (LGA) for gestational age at birth. A generalized linear model was used to estimate the effects of associated factors on the number of teeth emerged at one, two and three years. When the groups were combined, birth weight, birth order, maternal smoking during pregnancy and the children's height and head circumference at a given age all emerged as significant explanatory variables. The effect of maternal smoking was the reverse of that expected and evident only in the AGA and LGA groups. The associations with postnatal size were strongest in the SGA group and mainly low or negative in the LGA group. The birth-order effect was similar in all three groups.

Age Determination by Teeth

Proportionality at birth. Associations with weight, gestational age and sex.

501 small (SGA), 330 average (AGA) and 460 large for gestational age (LGA) babies were measured at birth. Head-chest, head-crown-rump length, and chest-crown-rump length ratios were used to evaluate the changing patterns of proportionality with increasing gestational age. The SGA group showed strong negative correlations for head-chest and head-length ratios, and positive correlations for chest-length ratios. The patterns were similar in the AGA group, only less evident. For all three measures of proportionality, correlations with gestational age in the LGA group were close to zero. In each group boys had higher head-chest ratios than girls.

Anthropometry

Growth and proportionality in early childhood. I. Within population variations.

Data on the postnatal growth patterns of 238 small-for-gestational age (SGA) and 241 large-for-gestational age (LGA) babies are presented. Three proportionality ratios were selected; and their changes in shape, by these indices, during the first 7 years are compared with a random sample of 284 children drawn from the same population. Highly significant differences (P less than 0.001) were found between the mean head-chest and head-length ratios for both sexes at birth; but mean chest-length ratios did not differ. Our findings show that these three measures of proportionality differ in their patterns of change over time; in the influence of birthweight group on their absolute values at each age; and the influence of sex within birthweight groups. At 7 years SGA children still had the highest and LGA children the lowest head-chest and head-stature ratios, and the differences were significant (P less than 0.01) for girls. This was mainly due to the relatively small heads of LGA girls. 46% of our sample had a head-chest ratio above unity at the age of 2 years. The "rule of thumb" criterion for the identification of malnourished children, based on the general principle that mean chest circumference overtakes head circumference by the age of 12 months, should not be too strictly applied.

Birth Weight

Proportionality of small-for-gestational age babies at birth: perinatal associations and postnatal sequelae.

Head and chest circumference and crown-rump length measurements were obtained for 413 small-for-gestational age (SGA) infants at birth; and head-chest, head-crown-rump and chest-crown rump ratios derived. There was an inverse correlation between head-chest ratios and gestational age, and boys had higher ratios than girls. First-born infants, and those whose mothers had pre-eclampsia had higher ratios than the rest, and higher ratios were associated with instrumental delivery. Higher ratios were also found for girls (but not boys) born to women of above average weight, and those who suffered birth asphyxia or other problems in the neonatal period. When adjustment was made for confounding between variables gestational age and sex were the only factors making a significant contribution to the variance in head-chest ratios at birth. SGA babies with relatively high head-chest ratios at birth grew faster than those with lower ratios during the first 6 mth of life. Girls with above-average ratios were heavier and had larger heads at the age of 7 yr, but no differences were found for either sex in any aspect of developmental ability at 7 yr associated with head-chest ratios at birth.

Anthropometry

Growth and proportionality in early childhood. III. Differences between babies of low birthweight in well-nourished and malnourished populations.

The growth patterns from birth to 7 yr of four groups of children are compared. They comprise: small-for-gestational age children in a highly favoured community born to (A) short mothers, (B) mothers of average height for their population; Guatemalan children living in a community where mild to moderate protein-calorie malnutrition was endemic. Data on a sample of children whose birthweights covered the normal range for gestational age were used as reference standards. At all ages and for almost all measures they were significantly larger than children in the other three groups. No differences were found between the boys in groups A and B; but girls in group A were lighter and shorter from 18 mth onwards. The Guatemalans were shorter and had smaller heads than group A from 12 mth onwards; and the boys were also lighter. No differences were found between the Guatemalans and group A for chest circumference in either sex from 2 yr onwards. Deficits in size at 4 yr of the Guatemalans compared with the Reference Sample ranged from 8.8% for stature, 6.8% head circumference, 5.9% weight, down to 3.9% for chest circumference. The differences between the four groups may broadly be taken to represent those due to low birthweight for gestational age, lower genetic potential, postnatal malnutrition, and their cumulative effects. Our findings offer a new perspective on their varying contributions to growth in size and shape during early childhood.

Body Height

Factors affecting development: similarities and differences among children who were small, average, and large for gestational age at birth.

The development of 118 small-for-gestational age (SGA), 137 average-for-gestational age (AGA), and 118 large-for-gestational age (LGA) children was assessed at 7 years. The contributions of different factors to the variance in developmental scores were investigated by multiple regression analyses. All three groups showed the powerful influence of social class on intellectual ability at this age; and in the SGA and AGA groups the gross and fine-motor skills of girls were superior to boys. Smoking had a small effect in the AGA group, and in the two extreme groups first-born children did slightly better than later-born. Hypertension was associated with reduced scores in the SGA group, and LGA children who had spontaneous vaginal deliveries had higher scores than those delivered instrumentally or by caesarean section. There was a significant positive correlation between gestational age and developmental scores in the AGA group; but in the SGA group the relationship was in the reverse direction. Social class and sex affect the development of most children aged 7 years. Other factors seem to manifest an effect only under specified conditions.

Child

Proportionality changes in the first year of life; the influence of weight for gestational age at birth.

Data on 55 small-for-gestational age (SGA), 56 average-for-gestational age (AGA) and 55 large-for-gestational age (LGA) infants whose growth had been monitored regularly from birth to 12 months are presented. SGA head-chest ratios were high at birth; but by 6 months they were very similar to AGA ratios, with values just below unity. Head-length ratios showed a steady decrement; SGA infants having the highest and LGA infants the lowest values at all ages. Chest-length ratios showed little change up to 6 months, with a steady decrease thereafter. Stem-stature ratios showed a similar pattern; and were confined within a narrow margin from 6 months onwards. These changes seem to be target orientated. We suggest the goal is that proportionality which enables the infant to attain the upright stature; and thus to sit, stand and walk at the appropriate time.

Anthropometry

Risk factors associated with small-for-dates and large-for-dates infants.

Relative risks were calculated to assess the potency of different factors associated with the two extremes of the birthweight distribution. Maternal height affected the chances of having a small-for-dates (SFD) or large-for-dates (LFD) baby to an equal and opposite extent; but the risks associated with maternal weight were greater for LFD than SFD infants. Smoking increased the SFD risk by 3.5 times, whereas the LFD risk was only reduced by a half. Pre-eclampsia was associated with a very high SFD risk (14.6); in the LFD group it was insignificantly raised. The LFD relative risk steadily rose with increasing parity, but in the SFD group it fluctuated around unity. Among multiparae the risks of an SFD or LFD infant when previous siblings had been of relatively low or high birthweight for gestational age, respectively, were much increased. Estimates of attributable risk showed that if pathological factors such as smoking, hypertensive disorders and congenital abnormalities could be completely eliminated the number of SFD babies in this population would be reduced by about 60%; conversely the number of LFD babies would be increased by about 30%.

Birth Weight