The relationship between breast-feeding and subsequent pregnancy in East Bhutan is examined, against the background of local attitudes to family planning. Ninety-eight mothers who had given birth 30–36 months earlier were interviewed. Semisolid supplementary feeding was introduced at a median age of 3 months. Median total duration of breast-feeding was 28 months, and day and night breast-feeding on demand was continued throughout. Median duration of postpartum amenorrhoea was 12 months, and was associated with the timing of the introduction of supplementary foods.

There was a significant association between the occurrence of a subsequent pregnancy and early termination of breast-feeding. The relationships between breast-feeding pattern and pregnancy interval are complex, and their relative influence changes with time. During the first year postpartum, infertility during lactational amenorrhoea is important. During the second year there is a strong negative effect on lactation from the next pregnancy. The only important reason for ceasing to breast-feed within 2 years seems to be a new pregnancy.

Menopause (cessation of menstruction) and the period surrounding it (climacterium) are often defined retrospectively by asking a woman the date of her last menstrual period (LMP). Based on a survey of 2000 women aged 45–64 in 1989 in Finland, this study examines (1) the relation between these definitions and women's own definitions of their climacteric status and of the cessation of menstruction and (2) the effect of menopausal and postmeno pausal hormone therapy and hysterectomy on the definition of menopause and climacterium. Agreement of the woman's own definition of her climacteric status and interval since LMP was 25% among current hormone users, 41% among hysterectomised women and 64% among those who were neither currently using hormones nor had been hysterectomised. Current hormone users defined the climacteric phase as longer than their LMP suggested. Current hormone use and hysterectomy had little effect on reported final cessation of menstrual periods. It is concluded that hysterectomy and hormone therapy shape women's thinking about the end of reproductive life, blur the concepts of menopause and postmenopause and confuse the measurement of age at menopause.

Contraceptive failure was an important determinant of fertility in China in the 1980s. Based on the data from the China Two-per-Thousand Fertility Survey, this study shows that about 7% of the general fertility rate of currently married women aged 15–49 for a 12-month period is attributed to contraceptive failure, mainly due to the high failure rate associated with IUD use. A number of demographic characteristics are associated with contraceptive use, and with contraceptive failure and its outcome. Relevant socioeconomic differentials are also identified.

Daily behaviour patterns in a hunter–gatherer community of Colombian Indians show that individual activities are regulated by ultradian behaviour cycles of about 2 hr and that these cycles can be synchronised by social interaction. A computer model was developed which simulated an artificial community and generated dynamic portraits of locomotor activity and social aggregation similar to those of the observed community of Colombian Indians. Social phase-locking of ultradian behaviour cycles occurred, contributing to the safety of group members and their economy of effort in gathering and related activities. Social synchronisation of ultradian behaviour cycles may also have occurred in early hominid groups.

A comparative study of 1100 women aged 25–45 years, users and non-users of modern methods of contraception, in the urban centres of Lahore and Faisalabad was conducted in 1991. The objective of the study was to investigate reproductive behaviour and the extent to which social, cultural and attitudinal variables, such as beliefs and values about family life, religiosity and fatalism, influence the fertility decision-making process. Preferences for smaller families were found to be consistently associated with modern attitudes and behaviour towards family and religious values and obligations. Family income, husband's occupation and religiosity offered no explanation of reproductive behaviour. It is concluded that cultural setting and tradition exert an important influence on reproductive behaviour, independent of economic development.

This study updates and extends estimates for unmet need and total demand for family planning for Jamaican women in the reproductive age group, 15–49. The findings suggest that, as yet unmet need for family planning was 22·7%, compared to 16% previously estimated.

Data on 2972 marriages in rural areas and 1180 marriages in urban areas of North Arcot Ambedkar district of South India, during 1982–88, were analysed. The mean age at marriage of females was 18·6 in the rural and 19·6 in the urban area. The proportion of females married before attaining the legal age of 18 years was higher among the rural community (36·8%) than in the urban community (28·9%). Univariate analysis revealed an association between early age at marriage and the socioeconomic variables religion, caste, consanguinity, marital distance, spousal age difference, education and occupation of both bride and bridegroom, and socioeconomic status of the family. Multivariate analysis showed an independent relationship of marital distance and bridegroom's occupation with early age at marriage of females in the rural area alone and the bridegroom's education in the urban area alone. Consanguinity, spousal age difference and bride's education were found to be independently related with early age at marriage of females in both rural and urban areas.

This study examines the relationships between consanguineous marriages and marriage payment, using data from two Muslim qaums living in urban and rural areas in Aligarh District, Uttar Pradesh, North India. Qaum and locality were found to have no significant association with the dowry system. Marriage payment is less common in consanguineous than in non-consanguineous marriages. However, the association between marriage payment and the type of marriage is significant at p<0·001. The dowry system is more prevalent among the higher socioeconomic groups, while the bride-wealth system is more common among the lower socioeconomic groups.

Despite the absence of a family planning programme, the prevalence of sterilisation in Brazil has increased substantially, such that it is used by relatively young women in poor areas of the country. Sterilisation is influenced more by the characteristics of the health service than by socioeconomic characteristics of the population.

This study uses data from thirteen Demographic and Health Surveys to examine effects of female migration on fertility in African cities. Contrary to expectations, migration from villages and towns in the 1980s and 1990s reduced total fertility rates in African cities by about one birth, from an estimated average of 5·55 in the absence of migration to 4·59. New arrivals experience much lower fertility in their first few years in cities than long term residents of similar age and parity. This results from the initial unmarried status of most migrants, high levels of spousal separation among new arrivals who are married, dramatic increases in use of modern methods of contraception after 2 years in cities, and continuation of traditionally long durations of postpartum abstinence. Accomodation of additional migrants thus appears consistent with efforts to reduce fertility in cities. Moreover, prospects for increased contraceptive prevalencein Africa may depend heavily on changes in population distribution that influence the demand for children, specifically movement to cities.

Test of the applicability of the hormonal theory of sex-dimorphic behaviour to adult women is achieved in this study by assembling measures of prenatal and adult androgen exposure, and a broad measure of gendered behaviour on a sample of white women aged 27–30. Androgen exposure in the second (and no other) trimester of fetal life, combined with and in interaction with adult androgens, masculinises women's behaviour and explains a substantial proportion of the within-sex variance in women's adult gendered behaviour.