Two methods of dietary recording, the 24-hr recall and the weighed dietary intake methods, are considered appropriate for estimating energy and nutrient intakes in studies of human fertility. The former method gives lower estimates than the latter, although weighed intakes may underestimate true intakes. Examination of food intakes of pregnant, lactating, and non-pregnant, non-lactating New Guinean women shows their diet to be less homogeneous than is generally assumed for groups in developing countries. As a result direct observations of food intake for a limited number of days are not sufficiently accurate for the estimation of intake of most of the nutrients examined. Rather the study design should reflect the variability of intakes of the nutrients and groups under consideration.

This paper develops a conceptual framework for examining the process of immunisation and explores the sociodemographic determinants of vaccination in Zambia. About 300 mothers with children under 3 years of age were interviewed in urban Lusaka. The analyses suggest that sociostructural, as well as cultural, processes influence the attrition process and immunisation programmes should focus on the uniqueness of each stage. In addition, programmes to improve women's education and to reduce male gender preferences are needed.

The change in parity and maternal age in Sweden accounts for the decline in the twinning rate from the 19th century to the middle of the 20th century. The later decline in twinning rate cannot be explained by changes in maternal age and parity. Fecundity appears to be higher in mothers of twins than in other mothers.

Medical Officer of Health reports for London boroughs, 1900–19, are analysed to determine the incidence of neonatal breast-feeding, duration of lactation, reasons for early supplementation and premature weaning, and their relationship with infant mortality. In a sample of 222,989 infants, breast-feeding rates were very high. Over 90% were breast-fed in the first month, almost 80% at 3 months, and over 70% at 6 months. The poorest boroughs had the highest rates of neonatal breast-feeding, but also a higher incidence of early supplementation and premature weaning. There was a significant positive correlation between breast-feeding and infant mortality due to poor maternal diet and health, poor nutritional quality of supplementary and substitute foods, and the use of an unhygienic feeding bottle. Energetic campaigns to counteract these problems probably contributed to the fall of infant mortality in this period.

The measurement of food intake has long been used to describe ‘adaptation’ to low energy intakes in certain tropical peoples. However, the methods available to quantify food intake are unlikely to reflect accurately real energy intakes in free living peoples. Alternatively, estimating energy expenditure shows some promise—particularly the measurement of basal metabolic rate (BMR). The BMR may be measured effectively in males, but females show wide intra-individual variation in BMR during their menstrual cycle, which makes BMR measurements more difficult to interpret in the context of adaptation. The use of double-labelled water may be the only method suitable to quantify and define ‘adaptation’ to low intakes in women.

The presence of a seasonal pattern of spontaneous abortion in the United States was found using data from the two most recent cycles of the National Survey of Family Growth (USA). The pattern was bimodal with peaks in March and August.

The effects of urbanisation, low income and rejuvenation of the population on life expectancy at birth and at 20, 40 and 65 years of age for males and females in Japan were examined twice, in 1980 and 1985. For males, urbanisation was the major factor determining life expectancy at birth and at age 20 years, and low income was the key determinant of decreased life expectancy except at 65 years of age. For females high income was the factor significantly decreasing life expectancy at 65 years of age in 1980, and rejuvenation of the population inversely influenced life expectancy except at birth in 1985. Life expectancy for all age groups in 1985 was significantly longer than in 1980 for both males and females.

An experimental breast-feeding education programme conducted at the Philippine General Hospital in Manila demonstrated that women could be motivated to improve their breast-feeding practices and lengthen their period of lactational amenorrhoea in comparison to a control group. Mothers who participated in the programme breast-fed their babies more frequently, delayed the introduction of regular supplements, used fewer bottles and pacifiers and maintained night feeding longer than mothers who were not exposed to the positive breast-feeding messages. The programme was successful in lengthening the period of amenorrhoea among women with elementary, high school, or technical school education, but not among college-educated women. Different educational approaches may be necessary for women of different education levels.

The two main ways in which disease and nutrition can influence fertility are by reducing fecundity or by extending the birth interval. Fecundity refers to reproductive ability, that is the potential to breed, as compared to fertility which denotes actual childbearing (McFalls & McFalls, 1984). Reduced fecundity, which is usually referred to as subfecundity, results from impairment of any of the biological aspects of reproduction, including coital inability, conceptive failure as well as pregnancy loss. Subfecundity is only one factor operating to reduce fertility; other factors include those governing mate exposure (both formation and dissolution of unions as well as exposure to intercourse within unions) and birth control.

Daily luteal progesterone levels were measured for 124 regularly menstruating women, aged 18–44, by radioimmunoassay of steroid levels in saliva. A consistent pattern of age variation in luteal function was found, with the lowest levels of progesterone in the 18–19-year-old and 40–44-year-old groups, the highest values in the 25–34 year olds, and intermediate values in the 20–24 and 35–39-year-old groups. The striking similarity of this pattern of age variation with empirically and theoretically generated curves of apparent fecundability, suggests that age-related changes in ovarian function may underlie observed age variation in fecundability.

Geographical differences in the frequencies of eight common surnames in Jutland (Denmark) are analysed using data from telephone directories of 121 exchanges. All the names showed a significant geographical surplus variance, which was divided into trend and patchiness components reflecting the history of the names. The surplus variance of surnames with restricted areas of origin was dominated by a large trend component; for surnames with an originally more even distribution, the patchiness component was dominant. The patterns of distribution were affected by processes which modelled natural selection with linkage disequilibrium. The combined patchiness within the clusters of exchanges gave information about patterns of local migration and level of social integration in the communities. Areas situated in boundary regions show high levels of patchiness.

Response consistency was examined by linking the records of women interviewed in the 1982 Sri Lanka Contraceptive Prevalence Survey with records from the same individuals followed up 3 years later. Seventy-eight percent of women reported identical year of birth in the two surveys, but only 58% were consistent for age at marriage. Data on sterilisation and number of children born were highly reliable, but wives' reports on husband's age and education were relatively weak. Multivariate analysis of the effects of socioeconomic factors on consistency in age reporting confirms that education is the most influential factor related to consistency, followed by religion and husband's occupation.

The measurement of short-term changes in maternal body composition during the post-partum period under field conditions poses many problems: (1) body composition techniques depend on the constancy of the proportions of components or their physical properties and are less suitable for measuring changes; (2) many of the techniques require expensive, technically sophisticated apparatus that is inappropriate to field conditions in many countries; (3) changes in body composition affect some areas of the body more than others so regional as well as whole body approaches are required. The measurements of body weight, triceps and subscapular skinfold thicknesses and upper arm circumference are essential measurements. These can be supplemented with further skinfold thicknesses and circumferences, and possibly body density and body water measurements. There is little to be gained by transforming anthropometric variables into whole body composition indices in these circumstances.

The prevalence and determinants of primary caesarean section in Jamaica were estimated from a survey of women aged 14–49 years. Among 2328 women reporting 2395 live hospital births during the period January 1984 to May 1989, the prevalence of caesarean section was 4·1%. Repeat caesarean sections accounted for 1·3% of the hospital births during that period. Of the medical complications studied, prolonged labour and/or cephalopelvic disproportion carried the highest risks of primary caesarean section, followed by breech presentation, maternal diabetes, a high birth-weight baby, maternal hypertension, and a low birth-weight baby. The risk of primary caesarean section increased with maternal age, decreased with parity, was higher for urban than for rural residents, and was higher for births in private versus government hospitals.

This research examines determinants of infant and child mortality in rural Egypt, primarily the effects of household economic status and the availability of health services. Certain features of the health service environment affect survival in the neonatal period. In early childhood, survival chances improve markedly as income increases and if the household depends almost exclusively on employment income. In infancy and in early childhood, mortality is strongly associated with region of residence and maternal demographic characteristics, and is weakly associated with parental schooling.

The relationship between subsequent lengths of lactational amenorrhoea for individual women in a prospective study of breast-feeding women in Bangladesh was studied. The data indicate that previous length of amenorrhoea has significant predictive value for the subsequent length of amenorrhoea. Information on previous experience with lactational amenorrhoea should be therefore incorporated into guidelines for the introduction of family planning during lactation.

A contraceptive study of rural Bangladeshi women indicated that the previous death of children, number of living children, desire for additional children and son preference were important determinants of contraceptive continuation. The importance of these factors varies to some extent with use of different contraceptive methods.

In a time series study of the USA from 1933 to 1984, fertility rates were associated with the suicide rates of those aged 15–44. The higher the fertility rate the lower the suicide rate for these age groups, for both whites and non-whites, and for both men and women. The results were seen as supporting Durkheim's theory of suicide.

The factors responsible for the return of fertility post-partum have not been very clearly defined. Several previous studies (Gross & Eastman, 1979; Diaz et al., 1988) have reported apparently major differences between populations in the duration of infertility associated with lactation. However, these differences may be related to the differences in study designs.

A simple and inexpensive method for monitoring child mortality in association with birth registration was introduced into the Southern Highlands of Papua New Guinea. Eight thousand two hundred and one newborn infants were registered in 1988, approximately 77% of all children born in that year. The risk of death by age 2 was determined from reports given by the mother on the present status of a previously born child at the time of a recent delivery or during clinic registration of the current birth. This was 91 per 1000 for the province and corresponds to a risk of death by age 1 of 77/1000 by extrapolation using standard lifetables. This method was validated by comparison with a continuing demographic surveillance system covering 30,000 people in the western part of the province. The new birth certificate has been an incentive to increase supervised delivery rates and to generate a register that can be used to increase vaccination coverage.