Maternal fatness and viability of preterm infants

To investigate the effect of maternal fatness on the mortality of infants born preterm up to the corrected age of 18 months 795 mother-infant pairs were studied. Maternal fatness was defined by Quetelet''s index (weight/(height²)) and all infants weighed less than 1850 g at birth. In 771 mother-infant pairs maternal age, complications of pregnancy, mode of delivery, parity, social class, and the baby''s sex and gestation were analysed by a logistic regression model for associations with infant mortality (but deaths from severe congenital abnormalities and those occurring during the first 48 hours after birth were excluded). In a subgroup of 284 mother-infant pairs all infant deaths except those from severe congenital abnormalities were analysed in association with the infant''s birth weight and gestation and the mother''s height and weight; this second analysis included another 24 infants who had died within 48 hours after birth. In the first analysis mortality overall was 7% (55/771), rising from 4% (71/173) in thin mothers (Quetelet''s index <20) to 15% (6/40) in mothers with grades II and III obesity (Quetelet''s index >30). After adjusting for major demographic and antenatal factors, including serious complications of pregnancy, maternal fatness was second in importance only to length of gestation in predicting death of infants born preterm. In the second analysis mortality overall was 15% (44/284), rising from 9% (5/53) in thin mothers to 47% (8/17) in mothers with grades II and III obesity. In both analyses the relative risk of death by 18 months post-term was nearly four times greater in infants born to obese mothers than in those born to thin mothers. In addition, maternal fatness was associated with reduced birth weight, whereas it is associated with macrosomia in term infants.These data differ fundamentally from those reported in full term babies of obese mothers. It is speculated that the altered metabolic milieu in obesity may reduce the ability of the fetus to adapt to extrauterine life if it is born preterm.     

Risk factors for perinatal mortality in Canada

A population-based computer record-linkage study of infant births and deaths in 1978 and 1979 in eight Canadian provinces (Quebec and Newfoundland were excluded) was undertaken to permit analysis of perinatal mortality in relation to maternal and infant characteristics. Perinatal mortality rates were significantly higher in nonurban than in urban areas (p < 0.05). A logistic regression model was used to assess the effects on perinatal mortality of variables reported on birth and stillbirth records. This model included length of gestation, infant''s birth weight and sex, number of previous births and number of previous stillbirths as well as an interaction term for length of gestation and birth weight. For early-neonatal mortality, odds ratios over 8 were observed for birth weight less than 2500 g or gestation less than 35 weeks. About 75% of early-neonatal mortality was attributable to low birth weight or fetal immaturity. Greater emphasis should be placed on the prevention of low birth weight.     

Size at birth,maternal nutritional status in pregnancy,and blood pressure at age 17: population based analysis.

OBJECTIVE: To assess the effect of size at birth, maternal nutrition, and body mass index on blood pressure in late adolescence. DESIGN: Population based analysis of birth weight corrected for gestational age, mother''s weight before pregnancy and weight gain in pregnancy, obtained from the Jerusalem perinatal study, and blood pressure and body mass index at age 17, available from military draft records. SETTING: Jerusalem, Israel. SUBJECTS: 10,883 subjects (6684 men and 4199 women) born in Jerusalem during 1974-6 and subsequently drafted to the army. MAIN OUTCOME MEASURES: Systolic and diastolic blood pressures measured at age 17 and their correlation with birth weight, size at birth, mother''s body mass index and weight gain during pregnancy, and height and weight at age 17. RESULTS: Systolic and diastolic blood pressures were significantly and positively correlated with body weight, height, body mass index at age 17, and with mother''s body weight and body mass index before pregnancy, but not with birth weight or mother''s weight gain in pregnancy. CONCLUSION: Variables reflecting poor intrauterine nutrition, including low maternal body mass index before pregnancy, poor maternal weight gain in pregnancy, and being born small for gestational age, were not associated with a higher blood pressure in late adolescence.     

Maternal nutrition in early and late pregnancy in relation to placental and fetal growth.

OBJECTIVE: To assess how nutrient intakes of mothers in early and late pregnancy influence placental and fetal growth. DESIGN: Prospective observational study. SETTING: Princess Anne Maternity Hospital, Southampton. SUBJECTS: 538 mothers who delivered at term. MAIN OUTCOME MEASURES: Placental and birth weights adjusted for the infant''s sex and duration of gestation. RESULTS: Mothers who had high carbohydrate intakes in early pregnancy had babies with lower placental and birth weights. Low maternal intakes of dairy and meat protein in late pregnancy were also associated with lower placental and birth weights. Placental weight fell by 49 g(95% confidence interval 16 g to 81 g; P=0.002) for each log g increase in intake of carbohydrate in early pregnancy and by 1.4 g (0.4 g to 2.4 g; P=0.005) for each g decrease in intake of dairy protein in late pregnancy. Birth weight fell by 165 g (49 g to 282 g; P=0.005) for each log g increase in carbohydrate intake in early pregnancy and by 3.1 g (0.3 g to 6.0 g; P=0.03) for each g decrease in meat protein intake in late pregnancy. These associations were independent of the mother''s height and body mass index and of strong relations between the mother''s birth weight and the placental and birth weights of her offspring. CONCLUSION: These findings suggest that a high carbohydrate intake in early pregnancy suppresses placental growth, especially if combined with a low dairy protein intake in late pregnancy. Such an effect could have long term consequences for the offspring''s risk of cardiovascular disease.     

Short term outcome in babies refused perinatal intensive care.

OBJECTIVE--To compare the mortality in babies refused admission to a regional perinatal centre with that in babies accepted for intensive care in the centre. DESIGN--Retrospective study with group comparison. SETTING--Based at the Royal Maternity Hospital, Belfast, with follow up of patients in all obstetric units in Northern Ireland. PATIENTS--Requests for transfer of 675 babies to the regional perinatal centre (prenatally and postnatally) were made from hospitals in Northern Ireland between January 1984 and December 1986. In all, 343 babies were refused admission to the centre, and complete data were available for 332 of them. These babies were either admitted to other neonatal intensive care units (261 babies) or remained in hospitals with only special care cots (71 babies). MAIN OUTCOME MEASURE--Short term mortality. RESULTS--Seventy of the 332 babies refused admission to the centre died compared with 51 of the 333 who were admitted. Multivariate analysis based on a logistic model showed a non-significant increase in mortality among babies treated in other intensive care units compared with babies treated in the centre (relative odds 1.2; 95% confidence interval 0.7 to 1.9). The increase in mortality in babies who remained in a special care baby unit, however, was significant (3.5; 1.7 to 7.0). This increase was particularly significant in babies born at less than or equal to 32 weeks'' gestation and who weighed less than 1500 g (8.4; 2.5 to 28.1). CONCLUSIONS--The results of the study confirm the benefits of neonatal intensive care and its particular value in improving survival in babies of low birth weight. As the babies were refused admission to the regional perinatal centre because intensive care cots were not available this deficiency should be corrected.     

Home births in England and Wales, 1979: perinatal mortality according to intended place of delivery.

A survey was carried out of all 8856 births occurring at home in England and Wales in 1979. Of these births, 67% had been booked for delivery at home, 21% had been booked for delivery in hospital, 3% had not been booked, and for 9% the intended place of delivery was unknown. The perinatal mortality varied almost 50-fold according to the intended place of delivery, ranging from 4.1/1000 births in those booked for delivery at home to 196.6/1000 unbooked births. Deliveries that occurred at home but had been booked for a hospital consultant unit were associated with a perinatal mortality of 67.5/1000. Births that had been booked for delivery at home included the smallest proportion of babies of low birth weight: 2.5% weighed 2500 g or less compared with 18% of those booked for consultant units and 29% of those not booked. Within these low birthweight groups there were noticeable differences in perinatal mortality; births booked to occur at home had the lowest mortality and unbooked births had the highest. Perinatal mortality among babies who weighed more than 2500 g was generally low irrespective of the intended place of delivery; the only exception was in babies whose delivery had not been booked. In all groups perinatal mortality was considerably higher in nulliparous than parous women. Women booking a delivery at home are clearly a selected group, and some may have been transferred to hospital during labour and were thus not included in the survey. Nevertheless, these data suggest that the perinatal mortality among births booked to occur at home is low, especially for parous women.     

Effects on pregnancy outcome of changing partner between first two births: prospective population study

Objective To compare the effects on pregnancy outcomes of changing partner between the first two births with having the same partner for both births.Design Prospective population study.Setting Norway.Participants 31 683 women who changed partner between their first two births and 456 458 women with the same partner for both births.Results After adjustment for maternal age and education, interval between births, and decade of birth, the risk of adverse pregnancy outcomes for the second birth was higher for women who changed partner between the first two births compared with those who had the same partner for both births: preterm birth (< 37 weeks; relative risk 2.0, 95% confidence interval 1.9 to 2.1), low birth weight (< 2500 g; 2.5, 2.3 to 2.6), and infant mortality (1.8, 1.6 to 2.1). For the first birth, the risk of these adverse pregnancy outcomes was only slightly higher for mothers who subsequently had a second birth with another partner.Conclusion Women who change partner between their first two births are at an increased risk of delivering a preterm, low birthweight baby with an increased risk of infant mortality compared with women who have the same partner for both births.     

When and why are babies weaned?

A prospective study was designed to investigate the weaning practices of 50 primiparous mothers whose babies were born between September 1976 and March 1978. The question whether the age of weaning influenced growth from birth to 6 months was also considered. The mothers and babies were seen in hospital and then at a follow-up clinic at 1, 2, 3, and 6 months. Details were taken of feeding practices, and measurements made of the babies'' weight, length, and subscapular and triceps skinfold thicknesses. Seventeen infants who were breastfed received their first solid food at a mean age of 13.8 weeks, compared with 8.3 weeks for the 33 bottle-fed infants. Most (38) mothers weaned because they though their babies were hungry (crying after a feed or demanding more frequent feeds, or both). The age of weaning did not influence weight gain, growth in length, or change in skinfold thicknesses. The results suggest that the "4-month rule" for weaning is unrealistic. The decision to wean should be based more on the mother''s interpretation of her baby''s needs than on age alone.     

Births in Great Britain resulting from assisted conception, 1978-87. MRC Working Party on Children Conceived by In Vitro Fertilisation.

OBJECTIVE--To describe the characteristics at birth of children conceived by in vitro fertilisation (IVF) or by gamete intrafallopian transfer (GIFT) and to assess whether they differ from those of children conceived naturally. DESIGN--Survey of children resulting from IVF or GIFT and comparison of their characteristics at birth with national statistics. SETTING--England, Scotland, and Wales from 1978 to 1987. SUBJECTS--1267 Pregnancies conceived by IVF or GIFT, which resulted in 1581 liveborn or stillborn children. MAIN OUTCOME MEASURES--Sex ratio, multiplicity, gestational age at birth, birth weight, stillbirth rate, perinatal and infant mortality, and prevalence of congenital malformations. RESULTS--The ratio of male to female births was 1.07:1; 23% (249/1092) of the deliveries were multiple births compared with 1% for natural conceptions; 24% (278) of 1015 deliveries were preterm compared with 6% in England and Wales; 32% (406) of 1269 babies weighed less than 2500 g compared with 7% in England and Wales. The high percentage of preterm deliveries and of low birthweight babies was largely, but not entirely, due to the high frequency of multiple births. The rate of stillbirth, perinatal mortality, and infant mortality were twice the national average, these excesses being due to the high frequency of multiple births. One or more major congenital malformations were detected during the first week of life in 35 (2.2%) of 1581 babies. This figure is comparable with population based estimates of the prevalence of congenital malformations. The types of malformations reported varied, and the number of each specific type was small. The health of the children was not evaluated beyond the perinatal period. CONCLUSIONS--Multiple pregnancies often result from assisted conception and are the main determinant of the outcome of the pregnancies and of the health of the children at the time of birth. Congenital malformations are comparatively rare, so larger numbers of children need to be studied before firm conclusions can be drawn. The pooling of data from different countries is recommended.     

Mother's weight in pregnancy and coronary heart disease in a cohort of Finnish men: follow up study.

OBJECTIVE: To determine whether restricted growth in utero is associated with an increased risk of coronary heart disease are among men in Finland, where rates of the disease are among the highest in the world. DESIGN: Follow up study. SETTING: Helsinki, Finland. SUBJECTS: 3302 men born in Helsinki University Central Hospital during 1924-33 who went to school in the city of Helsinki and were resident in Finalnd in 1971. MAIN OUTCOME MEASURES: Standardised mortality ratios for coronary heart disease. RESULTS: Men who were thin at birth, with low placental weight, had high death rates from coronary heart disease. Men whose mothers had a high body mass index in pregnancy also had high death rates. In a multivariate analysis the hazard ratio for coronary heart disease was 1.37 (95% confidence interval 1.20 to 1.57) (P < 0.0001) for every standard deviation decrease in ponderal index at birth and 1.24 (1.10 to 1.39) (P = 0.0004) for every standard deviation increase in mother''s body mass index. The effect of mother''s body mass index was restricted to mothers of below average stature. CONCLUSION: These findings suggest a new explanation for the epidemics of coronary heart disease that accompany Westernisation. Chronically malnourished women are short and light and their babies tend to be thin. The immediate effect of improved nutrition is that women become fat, which seems to increase the risk of coronary heart disease in the next generation. With continued improvements in nutrition, women become taller and heavier; their babies are adequately nourished; and maternal fatness no longer increases the risk of coronary heart disease, which therefore declines.     

Maternal and fetal nutrition in south India.

The relation between the nutrition of the mother and that of her baby was assessed in a south Indian community where malnutrition is common and women do not smoke. Unselected mothers and their infants of over 37 weeks'' gestation were studied in two groups: those who paid for their care (150) and a poorer group who did not (172). There were significnat differences between the paying and non-paying groups in maternal triceps skinfold thickness, infant weight, and infant length. Overall there was a significant positive correlation between maternal triceps thickness and infant weight, length, and triceps and subscapular skinfold thickness. The correlation with the infant head circumference was less significant. These findings are further evidence that the nutrition of the mother has an important effect on the nutrition of her baby and that malnutrition is an important reason why Indian babies are lighter than European ones.     

Change in social status and risk of low birth weight in Denmark: population based cohort study.

OBJECTIVE: To estimate the risk of having a low birthweight infant associated with changes in social, environmental, and genetic factors. DESIGN: Population based, historical cohort study using the Danish medical birth registry and Statistic Denmark''s fertility database. SUBJECTS: All women who had a low birthweight infant (< 2500 g) (index birth) and a subsequent liveborn infant (outcome birth) in Denmark between 1980 and 1992 (exposed cohort, n = 11,069) and a random sample of the population who gave birth to an infant weighing > or = 2500 g and to a subsequent liveborn infant (unexposed cohort, n = 10,211). MAIN OUTCOME MEASURES: Risk of having a low birthweight infant in the outcome birth as a function of changes in male partner, area of residence, type of job, and social status between the two births. RESULTS: Women in the exposed cohort showed a high risk (18.5%) of having a subsequent low birthweight infant while women in the unexposed cohort had a risk of 2.8%. After adjustment for initial social status, a decline in social status increased the absolute risk of having a low birthweight infant by about 5% in both cohorts, though this was significant only in the unexposed cohort. Change of male partner did not modify the risk of low birth weight in either cohort. CONCLUSION: Having had a low birthweight infant and a decline in social status are strong risk factors for having a low birthweight infant subsequently.     

Effects on birth weight and perinatal mortality of maternal dietary supplements in rural Gambia: 5 year randomised controlled trial .

OBJECTIVE: To test the efficacy in terms of birth weight and infant survival of a diet supplement programme in pregnant African women through a primary healthcare system. DESIGN: 5 year controlled trial of all pregnant women in 28 villages randomised to daily supplementation with high energy groundnut biscuits (4.3 MJ/day) for about 20 weeks before delivery (intervention) or after delivery (control). SETTING: Rural Gambia. SUBJECTS: Chronically undernourished women (twin bearers excluded), yielding 2047 singleton live births and 35 stillbirths. MAIN OUTCOME MEASURES: Birth weight; prevalence of low birth weight (< 2500 g); head circumference; birth length; gestational age; prevalence of stillbirths; neonatal and postneonatal mortality. RESULTS: Supplementation increased weight gain in pregnancy and significantly increased birth weight, particularly during the nutritionally debilitating hungry season (June to October). Weight gain increased by 201 g (P < 0.001) in the hungry season, by 94 g (P < 0.01) in the harvest season (November to May), and by 136 g (P < 0.001) over the whole year. The odds ratio for low birthweight babies in supplemented women was 0.61 (95% confidence interval 0.47 to 0.79, P < 0.001). Head circumference was significantly increased (P < 0.01), but by only 3.1 mm. Birth length and duration of gestation were not affected. Supplementation significantly reduced perinatal mortality: the odds ratio was 0.47 (0.23 to 0.99, P < 0.05) for stillbirths and 0.54 (0.35 to 0.85, P < 0.01) for all deaths in first week of life. Mortality after 7 days was unaffected. CONCLUSION: Prenatal dietary supplementation reduced retardation in intrauterine growth when effectively targeted at genuinely at-risk mothers. This was associated with a substantial reduction in the prevalence of stillbirths and in early neonatal mortality. The intervention can be successfully delivered through a primary healthcare system.     

Birth weight of offspring and mortality in the Renfrew and Paisley study: prospective observational study.

OBJECTIVE: To investigate the association between birth weight of offspring and mortality among fathers and mothers in the west of Scotland. DESIGN: Prospective observational study. PARTICIPANTS: 794 married couples in Renfrew district of the west of Scotland. MAIN OUTCOME MEASURES: Mortality from all causes and from cardiovascular disease over 15 year follow up. RESULTS: Women who had heavier babies were taller, had higher body mass index and better lung function, and were less likely to be smokers than mothers of lighter babies. Fathers of heavier babies were taller and less likely to be smokers than fathers of lighter babies. Mortality was inversely related to offspring''s birth weight for both mothers (relative rate for a 1 kg lower birth weight 1.82 (95% confidence interval 1.23 to 2.70)) and fathers (relative rate 1.35 (1.03 to 1.79)). For mortality from cardiovascular disease, inverse associations were seen for mothers (2.00 (1.18 to 3.33)) and fathers (1.52 (1.03 to 2.17)). Adjustment for blood pressure, plasma cholesterol, body mass index, height, social class, area based deprivation category, smoking, lung function, angina, bronchitis, and electrocardiographic evidence of ischaemia had little effect on these risk estimates, although levels of statistical significance were reduced. CONCLUSIONS: Birth weight of offspring was related inversely to mortality, from all causes and cardiovascular disease, in this cohort. The strength of this association was greater than would have been expected by the degree of concordance of birth weights across generations, but an extensive range of potential confounding factors could not account for the association. Mortality is therefore influenced by a factor related to birth weight that is transmissible across generations.     

Referral of mothers and infants for intensive care.

During 1975-7, 96 mothers were referred to University College Hospital for delivery from 39 other hospitals because their pregnancies were considered to be at very high risk. One hundred of the 111 infants born to the 96 mothers weighed 2500 g or less and 60 weighed 1500 g or less. A high proportion of the infants developed serious illnesses necessitating intensive care. The birth-weight-specific neonatal mortality rates of the infants were much lower than those of infants born in England and Wales as a whole and were also lower than those of the 370 infants transported to this hospital for intensive care after delivery elsewhere. Whenever possible mothers with very high-risk pregnancies should be referred for delivery to centres with full facilities for the intensive care of the mother, fetus, and newborn infant.     

The Scottish perinatal mortality survey.

Perinatal deaths in single births that occurred in Scotland during 1977 were investigated by case-record analysis. Causes of death were divided into nine categories, an extended version of the Aberdeen classification being used. Out of 1012 single perinatal deaths, 265 were due to fetal abnormality, which in 140 cases was malformation of the central nervous system. Of the 747 normally formed infants, 446 weighed 1500 g or more, of whom 82 died intra partum and 154 were born alive. The largest single cause of death was low birth weight in normally formed babies whose mothers had no complications of pregnancy (302 cases). Of these babies, 103 (34%) were growth-retarded. Rhesus incompatibility (16 deaths) and maternal diabetes (seven deaths) were not major causes of perinatal loss. These results were thought to be valuable in illustrating the main causes of perinatal mortality and directing attention to important issues. Hence a modified version of the study is being continued to see whether yearly audit by regional assessors is a feasible and practical way of monitoring trends in perinatal mortality.     

Birth weight in an African-American population living under moderate ecologic stress

The African-American population of McNary, Arizona, resides at an altitude of 2200 m. The lengthy winters are typically quite cold; the monthly mean temperature from November to April is 1.8 degrees C. Data from 318 singleton full-term births of African-American babies from 1949 to 1972 show a mean weight of 3095 g (s.d. = 427 g). At birth 1.9% of the babies weighed at least 4 kg; 9.7% weighed less than 2.5 kg. These data suggest that altitude may have influenced birth weight in this sample. Significant patterns in birth weight exist for sex, parity, mother's age, and severity of the winter preceding the year of birth. The birth weight of female babies born following warm winters is significantly lighter than those born during years following cold winters. There are relatively fewer high-birth-weight babies, in comparison to other African-American populations. Birth weight is also significantly lighter than three other African-American samples, even though African-American mothers of McNary had full-term professional care. Birth weight of African-American babies born in McNary is consistent with the overwhelming African ancestry of the African-American population of McNary. Sex differences in birth weight of babies born following cold winters can be ascribed to gender-related hereditary or physiologic factors at the level of the fetus. Maternal inactivity during particularly cold winters may be a contributing factor.     

Early discharge of infants of low birth weight: a prospective study.

A total of 495 African infants of low birth weight were discharged from Harari Maternity Hospital, Salisbury, between October 1972 and September 1973. Criteria used for discharge were (a) no clinical evidence of disease, (b) satisfactory feeding by mouth (breast or bottle or both), and (c) stable temperature control under normal room conditions. Of the 495 babies 264 fulfilled these criteria when they weighed 1801-1900 g (group 1), 99 when they weighed 1901-2000 g (group 2), and 132 (group 3) when they weighed 2001-2500 g. The overall follow-up rate of those infants living in greater Salisbury was 85-5%, the health visitor playing an important contributory role in their progress, especially those in group 1. More than two clinic visits in the first four to five weeks after discharge were essential for continuing weight gain in groups 1 and 2 but not in group 3. The mean daily weight gain for all babies at the end of four to five weeks was 26 g. Readmission rates for babies in groups 1,2, and 3 were 9-5%, 1%, and 0-8%, respectively, the largest single cause for readmission being bronchopneumonia associated with hypothermia. Altogether 60% of the readmissions occurred during the two winter months (June and July). Hypothermia, associated with low environmental temperatures played a significant part in morbidity and mortality, and twins, particularly in group 1, had a mortality rate three times greater than singletons in the same group. In general, even in underdeveloped communities singleton babies born outside the winter months with reasonable clinic or home visiting facilities can be discharged at a weight of 1800 g or more.     

Mothers' experiences of induction

Mothers of a random sample of 2182 legitimate live births were interviewed about their experiences of pregnancy, labour, and delivery. Of these, 24% reported that their labours were induced, and data about this from a subsample of mothers tallied with information obtained through the doctors in charge in 88% of cases. All but 3% of the mothers who were induced perceived some medical reason for the induction. The proportion of inductions in the 24 study areas ranged from 6% to 39%. A relatively small proportion of labours in “teaching” hospitals, small hospitals with less than 100 beds, and GP maternity hospitals were induced, but a comparatively high proportion of private patients had an induction. There was no clear association between induction and the mother''s age or parity. Despite being given more pain relief, those who were induced reported similar intensities of pain during the first and second stages of labour to those whose labour started spontaneously; they also reported that they had “bad pains” for a similar period. The period they had contractions was shorter for the induced than for those starting spontaneously, and the intensity of pain at delivery was rated somewhat less by those who were induced.There was no difference between induced babies and others in the proportion who were held by their mothers immediately after their birth. Two-fifths of the mothers who were induced would have liked more information about induction; and a similar proportion said they had not discussed induction with a doctor, midwife, or nurse during their pregnancy. Only 17% of the mothers who had an induction said they would prefer to be induced if they had another baby. This contrasts with 63% of those who had epidural analgesia who would opt for the same procedure next time, while 83% of those who had had a baby in hospital, and 91% of those having had a home birth, would want their next baby in the same type of place.