V.A. Moar

Perinatal morbidity and mortality in small-for-dates babies: The relative importance of some maternal factors

Data on 538 mothers and their small-for-dates babies were analysed to ascertain whether any specific maternal factors were associated with increased perinatal risks. There were 34 deaths; 21 (62%) of these babies had major congenital abnormalities. Among the survivors perinatal morbidity was also markedly increased when the baby was abnormal. No direct associations were found between abnormal babies and any maternal factors. Few differences were found in the incidence of mortality and morbidity factors according to maternal height, weight, weight gain in pregnancy, social class and smoking habits. There was a significantly higher death rate when the mother was pre-eclamptic, and the incidence of seven other morbidity factors was also increased. The only adverse effects of maternal hypertension without pre-eclampsia was a higher instrumental delivery rate, and more of these babies were tube-fed. There were only significantly more perinatal deaths among multiparous women whose previous babies had been of average birthweight. This was due to an excess of congenitally abnormal babies in this group. Only 35% small-for-dates babies escaped any perinatal problems.

Hypertension during pregnancy with and without specific treatment; the development of the children at the age of four years.

In a controlled trial pregnant women who were hypertensive before the 28th week of gestation were randomly allocated to treatment with methyldopa or no anti‐hypertensive treatment. The children from these pregnancies have been re‐examined at four years of age and their development compared with a random sample from the same maternity hospital population. Their health, height, weight, and the incidence of sight, hearing and speech problems did not differ. None had gross neurological abnormalities. Boys in the treated hypertensive group had significantly smaller heads than in the other two groups, but there was no correlation between head circumference and developmental score in this group (r = 0.020). On average the children in the random sample were the most advanced when assessed a global score of development. In each developmental sector the mean score for the treated hypertensive group was consistently higher than the untreated hypertensive group. We conclude that maternal hypertension is associated with slight developmental delay in early childhood. There are some indications that treatment with methyldopa may reduce this effect.

Risk factors associated with small‐for‐dates and large‐for‐dates infants

Summary. 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 (SED) 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%.

Children of deviant birthweight at the age of seven years: health, handicap, size and developmental status

138 small-for-dates (SFD), 138 average-for-dates (AFD) and 136 large-for-dates (LFD) children who had been followed up from birth were examined at the age of 7 years. Nine children had major congenital abnormalities (SFD 5, AFD 2, LFD 2). In addition gross and/or fine motor incoordination was noted in 25 children (SFD 9, AFD 10, LFD 6). There were no differences between the groups in the incidence of chronic or specific ill-health, hearing, sight and speech defects. Highly significant differences were found between the groups for weight, height, head circumference and triceps skinfold thickness; and significant differences were also found between the total developmental scores in the three groups. In every case SFD children had the lowest and LFD children the highest mean values. Within each group analyses were made of 22 parental, pregnancy, perinatal and postnatal factors which might affect growth or development. The net effects of those factors for which significant differences had been found were then assessed, adjustment being made for confounding between variables. In all three groups the childrens genetic potential for size was strongly evident by this age, and boys had larger heads than girls. All three groups showed the powerful influence of social class on intellectual ability; and sex on gross and fine-motor function. The other main contributor to developmental differences in the AFD group was gestational age. In the SFD group maternal hypertension was associated with slightly decreased intellectual ability, and in all areas first-born SFD children performed better than subsequent born. Among LFD children instrumental delivery had an adverse effect on all areas of ability, and first-born children had higher intellectual scores. When all the children were considered together and birthweight included as an additional variable the differences in developmental scores between the groups were much reduced. In the SFD and LFD groups some significant correlations were found between size and developmental scores; but none were found among AFD children.

INCREASED BILIRUBIN LEVELS IN NEONATES AFTER INDUCTION OF LABOUR BY INTRAVENOUS PROSTAGLANDIN E2 OR OXYTOCIN

Abstract Four groups of thirty primigravidas and their infants were studied prospectively. Group A had labour induced by intravenous oxytocin, group B by intravenous prostaglandin E 2 , and group C by extra-amniotic prostaglandin E 2 . In the fourth group (D), labour was spontaneous throughout. Mean bilirubin levels on day 5 were significantly higher in groups A and B than in group D. The level in group C did not differ significantly from groups A, B, or D, although the mean inducibility rating in this group was lower. The mean serum-bilirubin level was significantly lower after caesarean section than after assisted vaginal delivery. Mean serum-bilirubin levels were not affected by the previous use of oral contraceptives, maternal smoking-habits, or methods of infant feeding. The data suggest that the neonatal hyperbilirubinaemia observed may be due to the artificial interruption of pregnancy, although a direct drug effect cannot be excluded.

NEONATAL HEAD CIRCUMFERENCE AND THE TREATMENT OF MATERNAL HYPERTENSION

In a random controlled trial of methyldopa for the treatment of hypertension in pregnancy presenting before 28 weeks gestation, the newborn in the treated group had relatively smaller head circumferences. This difference persisted at two months of age when correction had been made for birth weight, gestation and sex, but was no longer detectable at six or twelve months. Within the treated group no relationship was found between neonatal head circumference and the total amount or duration of methyldopa received during pregnancy. Comparison of treated and untreated groups according to the time of entry to the study showed that significant differences in neonatal head circumference were only present in patients who entered between 16 and 20 weeks gestation. It is possible that this could be a sensitive period for the interaction of fetal head growth and the onset of specific treatment in hypertensive pregnancy.

Hypertension during pregnancy, with and without specific hypotensive treatment

In a prospective study, women who were hypertensive before the 28th wk of gestation were randomly allocated into two groups: those who received specific hypotensive therapy (Ht) and those who did not (Hu). The outcome was compared with a random sample of the hospital population (S) ascertained after delivery. In both hypertensive groups there was a higher incidence of clinical signs of possible fetal distress and instrumental delivery. Although there was no difference between the groups in the distribution of birthweight above and below the mean for gestational age, the treated hypertensive group had an excess of infants with relatively smaller head circumferences for their gestational age compared with both the untreated hypertensive group and the hospital sample. Tube-feeding was also more frequent in the treated hypertensive group. In the untreated hypertensive group there were more infants whose neurological status was categorized as questionable or abnormal in the neonatal period, compared with the sample. The different problems encountered by infants in the two hypertensive groups emphasized the need for further study of these babies. Their development during the first year of life will be examined in a subsequent paper.

Hypertension during pregnancy, with and without specific hypotensive treatment: II. The growth and development of the infant in the first year of life

The growth and development of three groups of infants were prospectively assessed from birth to 12 mth. In two groups the mothers had been hypertensive before the 28th wk of gestation; one group was randomly allocated to specific hypotensive therapy, the other group was allocated to no specific treatment. The third group was a sample of the hospital population. General health, and the incidence of sight and hearing problems did not differ. Infants in the treated hypertensive group had had more perinatal problems, and there was an excess of infants with relatively small heads for their gestational age at birth. At 6 mth their heads were still smaller than the hospital sample, but by the age of 1 yr the difference was no longer present. The neurological status of infants in the untreated hypertensive group was less favourable in the neonatal period, and there was still an excess of infants in this group rated questionable on neurological assessment at the age of 12 mth. In both hypertensive groups there was an excess of infants with delayed fine-motor function at 6 mth, and in the untreated group there was an excess with delayed gross-motor function at 12 mth compared with the hospital sample. Our varied findings draw attention to the dangers of assessing the effects of different pregnancy conditions in terms of neonatal mortality and morbidity alone. Our date indicate that follow-up should extend for longer than 12 mth when the effects of adverse pregnancy factors and their management are under consideration. Further evaluation will be made when these children are 4 yr old.

Growth in the first four years: II. Diversity within groups of small-for-dates and large-for-dates babies

238 small-for-dates (SFD), 246 average-for-dates (AFD) and 241 large-for-dates (LFD) infants were personally examined at birth, and measured thereafter in their own homes at the ages of 2, 6, 12 and 18 months, 2, 3 and 4 years. At each age weight, length or height, and head circumference measures in the SFD and LFD groups were distributed around the appropriate sex AFD mean values. In both extreme groups major shifts towards the mean occurred in the first six months for all three measures. From one year onwards only small within group fluctuations were seen. Correlations between one and four year values for weight, height and head circumference were high. At four years about 50% SFD children were within 1 S.D. of the mean, and 10% were still very small. Slightly more LFD children (55-60%) were near to the mean at this age, particularly for their head circumference values (70%), and only about 8% LFD children had very large heads. Trajectories of individual SFD and LFD children illustrate the great diversity of growth patterns within and between groups.

Maternal hypertension with superimposed pre‐eclampsia: effects on child development at 7½ years

Summary. Children born to women participating in a prospective study of hypertension during pregnancy were followed up from birth. Data on growth and development at the age of 7½ years of 56 children whose mothers had superimposed pre‐eclampsia are compared with results of 176 children whose mothers had only hypertension. Perinatal mortality in the hypertension‐only group was similar to that for the hospital population in general at the time of their birth; but in the group who developed pre‐eclampsia it was significantly higher. At the age of 7½ years no differences were found in the frequency of health, handicap, sight and hearing problems, weight, height, head circumference, and standing and supine blood pressures. For six aspects of intellectual development children in the pre‐eclampsia group had slightly higher mean scores; and in one of these, ‘perceptual matching’ the difference was significant after adjustment had been made for confounding variables. Pre‐eclampsia superimposed on hypertension does not increase the likelihood of impaired growth and development among children who survive the perinatal period.