Maternity histories from residents of a Pacific Island society, Tokelau, and migrants to New Zealand, are analysed using life table techniques. Inter-cohort differentials in patterns of family formation were found in the total Tokelau-origin population. The process of accelerated timing and spacing of pregnancies was more pronounced among migrants who tended to marry later, be pregnant at marriage, have shorter inter-pregnancy intervals at lower parities and to show evidence of family limitation occurring at higher parities. These results point to the significance of changing patterns of social control on strategies of family building.

Using routinely collected data for 184,000 Scottish singleton live births in 1980–82, nine maternal factors were related to changes in the distribution of birthweight for given gestational age. Maternal height and marital status were associated with overall shifts in the distribution. In contrast, social class, a previous perinatal death or two or more previous spontaneous abortions in multiparae were primarily associated with increased risk of a small-for-gestational-age infant. A history of caesarean section or three or more previous live births was associated with increased risk of a large-for-gestational-age infant. The results of this population study were generally consistent with reported hospital-based findings.

Many physiological functions of the human body as well as human behaviour are regulated by endogenous rhythms. While circadian rhythms with periods of about 24 hr serve to adjust body functions and patterns of behaviour to the geophysical day/night cycle, intrinsic rhythms with shorter periods, called ultradian cycles, subdivide the 24-hr interval. For example, motor activity, perception and cognitive style are influenced by an intrinsic cycle of about 1½ hr. Despite numerous laboratory studies, the functions of ultradian rhythms are as yet unknown. In this field study, endogenous short-term cycles were observed in the daily behavioural patterns of illiterate individuals living without artificial time-cues in a small East Indian village community. Time series analysis of the result provides additional evidence that behavioural patterns of adults as well as infants and children living under natural conditions may be regulated by intrinsic rhythms with period intervals of 1–3 hr. Furthermore ultradian behaviour cycles in single subjects can be synchronized within a common time-frame. This suggests that intrinsic ultradian cycles may serve to organize daily behaviour patterns for optimal co-ordination and satisfaction of individual and common demands.

This paper discusses polygynous marriages in rural Bangladesh, using marital status and birth registration data from the Demographic Surveillance System of the International Centre for Diarrhoeal Disease Research, for the period 1975–79. Of all the marriages recorded during this period about 5% were polygynous. To identify the women polygynously married, 1974 census data of the DSS area were used. The difference in age at marriage between the polygynous groom and his subsequent wife was 15 years on average. The socioeconomic indicators studied were education, occupation and area of dwelling space. In general, these indicators differentially influence polygynous marriage. The fertility differentials between women in monogamous marriages were significantly higher than between the women in polygynous unions.

This paper examines the question of whether there are consistent regional variations in the level and shape of the age-specific natural fertility curve using data for 45 less-developed countries drawn from a recent US Census Bureau compilation. In general there do not appear to be such variations. A remarkably consistent age pattern of natural fertility emerges, once the rates have been normalized and an adjustment made for age at first exposure to the risk of pregnancy. The results strongly support Coale's original natural fertility paradigm.

In data from the Sri Lanka Fertility Survey, 1975, the cessation of childbearing is examined among women who have never used contraception. They tend to cease childbearing relatively early, and therefore are infertile for longer periods during their marriages. It is probably age of the first child that influences decisions on future fertility.

Growth and psychological data for 74 participants in the Fels Longitudinal Study are analysed to determine the influence of the relative timing of maturation upon psychological attributes related to interests, abilities, self-confidence, peer relationships, and future goals. It is suggested that neither age at peak height velocity for either sex, nor age of menarche for girls, represents an adequate measurement of relative maturity status. A new variable that can be used for both sexes, relative maturity, is suggested and computed using peak height velocity as well as the additional information gained from the percentage of adult stature achieved at that time.

Results of separate significance tests using peak height velocity and relative maturity as independent variables reveal early maturers to be more self-confident in specific abilities and also more gregarious during adolescence with higher educational and vocational expectations for the future, while the later maturer is less likely to be influenced by his peers and to have less ambitious long-range goals.

Contraceptive choice in the first 1075 acceptors at an urban clinic in Lagos has been studied. An IUD was the most popular choice followed by the injectable contraceptive and the pill. Interval tubal ligation was chosen by some patients. Acceptors of injectables were older women of high parity and lower educational standard while pill acceptors were of lower parity and higher educational level. The IUD was acceptable to all ages and parities except those with only one child or none.

Loss to follow-up and the wish to plan another pregnancy were the commonest reasons for discontinuing contraception. Medical reasons for discontinuing the IUD were pain, menstrual disorder, accidental pregnancy and expulsion/perforation, and for discontinuing injectables the reasons were menstrual disorder, accidental pregnancy and raised blood pressure.

A survey of consanguineous marriages in Japan was conducted in September 1983 using questionnaires. The number of couples studied was 9225, chosen from six widely different areas of Japan. Recommendation by parents or relatives was the most frequent reason for consanguineous marriage, for both husbands and wives, followed by knowledge of the partner by relatives.

The rate of consanguineous marriage on the recommendation of parents or relatives was higher in endogamy, arranged marriages, childhood friends, and groups in which there is external pressure for marriage. It was lower in love match marriages, school, workplace and social gatherings that give opportunities for meeting, and where there was personal marital motivation.

Many studies have suggested that following the experience of ‘stressful’ life events the risks of accidents, myocardial infarctions and other diseases are elevated. In the OPCS Longitudinal Study, routinely collected data on deaths, and deaths of a spouse occurring in a 1% sample of the population of England and Wales in the period 1971–81 are linked together, and with 1971 Census records of sample members. The timing and patterns of death following the very stressful event of conjugal bereavement may thus be analysed.

Overall the mortality of widowers was about 10% in excess of that in all males in the sample whereas that of widows was only slightly raised. Some increases in death rates shortly after widow(er)hood are observed. Unusually, these increases in all-cause mortality rates are more marked in widows than in widowers, with a two-fold increase in mortality from all causes in the first month after widowhood. Marked peaks of post-bereavement mortality from accidents and violent causes are clear in both sexes. Possible explanations for the increased mortality rates are examined.