Timing and sequence of resuming ovulation and menstruation after childbirth

Abstract This report presents results from a prospective study of post-partum physiology conducted by the Obstetric Department of the Catholic University of Chile during 1965-68. The study was undertaken to gain more detailed knowledge than is currently available about the relationship between a woman's lactation experience and the return of her post-partum reproductive function. 200 mothers were successfully followed and information collected about their intervals from childbirth to first ovulation and to first bleeding day, together with a detailed history of breast feeding. In these histories, days of 'full breast feeding' (infant exclusively breast-fed) are distinguished from days of 'partial breast feeding' (infant given supplementary nutrition besides breast milk). Elaborate pains were taken to establish the date of first ovulation, four different techniques being used concurrently during a series of weekly contacts with each patient.     

Frequency and timing of intercourse: Its relation to the probability of conception

Abstract This paper describes a simple study of the chance of conception assuming a fixed-length menstrual cycle, a specific probability distribution for the day of ovulation, and a broad and a narrow fertile period. Eight different patterns of intercourse throughout the cycle are considered with frequency of intercourse ranging between 5 and 12 times per cycle. Results are given in terms of chance of conception and in terms of waiting times until conception.     

Projecting future utilization of medically assisted fertility treatments

This study estimates the future utilization of medically assisted fertility treatments in Australia, focusing on assisted reproductive technologies (ARTs), intrauterine insemination (IUI), and ovulation induction. A multistate cohort component population projection model is used to determine future fertility rates from 2016 to 2026 by age and education level. These are combined with information on recent trends in use and success rates to indirectly estimate future age-specific probabilities of fertility treatment utilization. The number of ART cycles is expected to increase by 61 per cent between 2016 and 2026 if treatment success rates remain at 2015 levels, or by 34 per cent if recent improvements in ART success rates continue. The model also predicts that numbers of IUI cycles and ovulation induction cycles will decrease by 17 and 3 per cent, respectively. This research confirms the importance of including both technological improvements and socio-demographic changes when predicting future fertility treatment utilization.     

Tonga: family planning survey

A survey was carried out in 1975 in Tonga to determine how many families are practicing family planning. Public health nurses visited every household except the Niuas and remote islands. 4253 women out of the total of 9307 married women aged 15-44 years were using a contraceptive (45.7%). The percentage of users ranged from 4.5% in Ha'afeva District to 63.6% in the district of Kolonga. 60% of the users practice effective methods such as the pill, Depo-Provera, IUD, or sterilization; 23% use the condom, and 17% rely on withdrawal, calendar ovulation, or rhythm.     

The Contraceptive Role of Breastfeeding

We review (1) neuro-hormonal mechanisms by which breastfeeding postpones the return of ovulation and menstruation after birth, and (2) various statistical procedures used to analyse this effect in human populations. This review reveals that the biology and the statistical procedures are incompatible. We propose a statistical approach, compatible with present knowledge of physiology, that differentiates between ovulation-inhibiting mechanisms at birth and the weakening of these inhibitions thereafter, so that it is possible to investigate the effects on these mechanisms due to breastfeeding and to other determinants such as mother's age. An empirical test with typical recall data indicates that full breastfeeding postpones ovulation longer than does supplemented breastfeeding, and that both have stronger contraceptive effects than has previously been thought.     

The Catholic response to the population problem

A survey of efforts led or sponsored by the Catholic church in response to the population problem in the Philippines. These efforts stem from the Church's belief that population growth is related to the overall picture of development, and that priority must go to social and economic justice. The Catholic Church of the Philippines (to which 85% of the population belong) views it as a problem basically involving care of people, and directs its efforts primarily at internal human sexual control rather than external contraceptive control. Family Life Education began as a program in the church in the 1960s. Efforts by priests, nuns, and lay leaders in Mindanao eventually resulted in counseling in husband-wife relations, marriage commitment, human sexuality, parent-child relations, and responsible parenthood, and to the creation of college courses to prepare teachers in tackling sex education. A program offering natural family planning was also started, initially for employees of a packing firm and later expanding throughout the province. In 1975, the program was launched in Manila, and a year later had 3 family life centers. The ovulation (or Billings) method is offered -- an advantage to low income people because it does not require purchase of a thermometer. Success of this method requires a sense of responsibility on the part of both husband and wife. Widespread international interest in the ovulation method has led to formation of an International Federation for Family Life Promotion, to which the Philippine Federation for Natural Family Planning has applied for membership. The IFFLP is working with the WHO Human Reproduction Unit on 2 projects, part of one of them (a field trial for evaluation) being conducted in Iligan City, Iloilo City, and Manila. Among the concerns of the IFFLP-WHO collaboration is developing a standardized Natural Family Planning curriculum or educational package.     

Prospective study of birth interval dynamics in rural Bangladesh

Abstract A group of 209 married, fecund women in rural Bangladesh were studied prospectively for 24 months from 1969 to 1971 to define some of the biological and sociological factors relating to fertility performance. These women were selected from a larger study population of 112,000 that had been followed with a daily house-to-house vital registration programme since 1966. The selected women were interviewed bi-weekly and were asked questions about menstruation, pregnancy, lactation, husband's occupational absences, and monthly urine tests for pregnancy were taken. The results for 193 non-contracepting women revealed that the seasonal pattern of births previously observed in this population could be associated with a corresponding seasonal pattern of conceptions and that this was due to a seasonal trend in fecundability. The highest conception rates were in the coolest months of the year. Post-partum lactational amenorrhoea was very prolonged, averaging 17 months for women with a surviving child. The appearance of the first post-partum menstrual flow (onset of ovulation) also had a seasonal trend which could not be adequately explained. The median waiting time to conception, once menstruation had resumed was eight months. This interval was influenced by seasonal fluctuations, as well as by the age of women and by husbands' absences. The foetal wastage rate was 15·0 per 100 conceptions, with 62 per cent of the foetal losses occurring during the second month of gestation. Overall, the average birth interval was 33 months, with the prolonged lactational amenorrhoea accounting for almost 45 per cent of this interval. From the Department of Population Dynamics, Johns Hopkins University, School of Hygiene and Public Health, Baltimore, Maryland 21205.     

The seasonality of conception

Individual data on menstrual cycles of noncontracepting women living in Western countries were used in order to verify whether the biological seasonality of conception persists after sexual behavior is controlled for. Episodes of intercourse were recorded daily, and the time of ovulation was detected by a marker We find that the seasonality of conception changes with woman's age and frequency of episodes of sexual intercourse. In particular; for women aged 27-31 having only one act of intercourse during the six most fertile days of the menstrual cycle, the seasonality of fecundability is stronger In this age group in the Northern Hemisphere, if seasonality of acts of sexual intercourse is controlled, the monthly distribution of probability of conception is bimodal, with two maxima (September and January) and two minima (December and March). When unobserved characteristics of the couples are considered, this seasonal pattern of conception persists.     

Prospective study of birth interval dynamics in rural Bangladesh

A group of 209 married, fecund women in rural Bangladesh were studied prospectively for 24 months from 1969 to 1971 to define some of the biological and sociological factors relating to fertility performance. These women were selected from a larger study population of 112,000 that had been followed with a daily house-to-house vital registration programme since 1966. The selected women were interviewed bi-weekly and were asked questions about menstruation, pregnancy, lactation, husband's occupational absences, and monthly urine tests for pregnancy were taken. The results for 193 non-contracepting women revealed that the seasonal pattern of births previously observed in this population could be associated with a corresponding seasonal pattern of conceptions and that this was due to a seasonal trend in fecundability. The highest conception rates were in the coolest months of the year. Post-partum lactational amenorrhoea was very prolonged, averaging 17 months for women with a surviving child. The appearance of the first post-partum menstrual flow (onset of ovulation) also had a seasonal trend which could not be adequately explained. The median waiting time to conception, once menstruation had resumed was eight months. This interval was influenced by seasonal fluctuations, as well as by the age of women and by husbands' absences. The foetal wastage rate was 15·0 per 100 conceptions, with 62 per cent of the foetal losses occurring during the second month of gestation. Overall, the average birth interval was 33 months, with the prolonged lactational amenorrhoea accounting for almost 45 per cent of this interval.      

Breastfeeding as a means of contraception

The University of the Philippines Institute of Public Health (UPIPH) and the Family Health International (FHI) brought together health professionals, nutritionists, and family planning experts from different parts of the world to share and gain insights into the issue of breastfeeding and contraception. The participants met in Manila in 1983 and analyzed research findings on breastfeeding and discussed their implications relevant to nutrition and family planning policies and programs. Studies conducted in several countries show a general decline of breastfeeding practice in both urban and rural areas. The issue appears to be not whether women in developing countries breastfeed their infants but for how long. Popkin cites a study in Thailand, which showed very little change in the proportion of babies ever breastfed but large declines in the duration of breastfeeding from 1969-79. In the Philippines, national surveys since 1973 indicate that mothers throughout the country practice breastfeeding but do so for a relatively short period. Scientific data supporting the folk belief that breastfeeding delays the return of fertility after childbirth is growing. The phenomenon is believed to be governed by a sophisticated control mechanism in the female reproductive system. Some researchers suggest that prolactin may be responsible for the delay of fertility in breastfeeding mothers. In a series of studies done in the Philippines and Australia, researchers Barbara Gross and C.J. Eastman found that high prolactin levels were almost always associated with proloned amenorrhea during lactation. A decline in prolactin concentrations accompanied the resumption of menstruation. Gross and Eastman found evidence of ovulation before the 1st menses in only 1 out of 54 fully breastfeeding mothers, or less than 2%. This implies that at least the first few menses of most fully breastfeeding mothers are not accompanied by ovulation, suggesting that breastfeeding continues to affect fertility even after the resumption of breastfeeding. Zablan's study in the Philippine analyzed the various factors contributing to fertility reduction. Breastfeeding appeared to have the greatest impact on the Filipino woman's level of fertility. Zablan points out that, while breastfeeding is a major factor influencing fertility in the Philippines, it "can be relied upon only to postpone childbearing (and then only at the aggregate level), but not to prevent childbearing altogether." Much work needs to be done to help people realize the value of breastfeeding, to encourage mothers to practice it, and to do so for as long as possible.     

Phenological studies on the wing dimorphism of a semi-aquatic bug,Microvelia douglasi (Heteroptera: Veliidae)

Summary Seasonal changes in the percentage of macropterous individuals in natural population ofMicrovelia douglasi in permanent habitats were investigated in Shimane, western part of Japan. Macropterous forms of 5th instar nymphs occurred most frequently from late June to early July. However, the seasonal appearance of macropterous adults differed between habitats and years. There were significant effects of density, temperature, photoperiod and food availability on the percentage of macropters under laboratory conditions. The percentage of macropterous forms generally increased with density, but the mode of the response was modified by temperature, photoperiod and food availability. When insects were reared under long day photperiod (16L8D) with abundant food (0.5–1.0 g/container/day), the percentage of macroptery varied most among the different density treatments at the intermediate temperature (24°C) and the difference was reduced at higher temperature (28° and 32°C). Effects of temperature were small under the short day photoperiod (12L12D). Under 12L12D photoperiod sensitivity of density responses were higher at 32°C and lower at 24°C than those under 15L8D photoperiod. When the insects were supplied with food every other day, the density response became obscure. Ecological significance of environmental responses in the wing morph determination was discussed in relation to the heterogeneous environment of water surface.     

A Comparison of Affect Ratings Obtained with Ecological Momentary Assessment and the Day Reconstruction Method

Measurement of affective states in everyday life is of fundamental importance in many types of quality of life, health, and psychological research. Ecological momentary assessment (EMA) is the recognized method of choice, but the respondent burden can be high. The day reconstruction method (DRM) was developed by Kahneman and colleagues (Science, 2004, 306, 1776–1780) to assess affect, activities and time use in everyday life. We sought to validate DRM affect ratings by comparison with contemporaneous EMA ratings in a sample of 94 working women monitored over work and leisure days. Six EMA ratings of happiness, tiredness, stress, and anger/frustration were obtained over each 24 h period, and were compared with DRM ratings for the same hour, recorded retrospectively at the end of the day. Similar profiles of affect intensity were recorded with the two techniques. The between-person correlations adjusted for attenuation ranged from 0.58 (stress, working day) to 0.90 (happiness, leisure day). The strength of associations was not related to age, educational attainment, or depressed mood. We conclude that the DRM provides reasonably reliable estimates both of the intensity of affect and variations in affect over the day, so is a valuable instrument for the measurement of everyday experience in health and social research.     

Time Use Patterns Between Maintenance,Subsistence and Leisure Activities: A Case Study in China

The Chinese government conducted its first time use survey of the activities of Chinese individuals in 2008. Activities were classified into three broad types, maintenance activities, subsistence activities and leisure activities. Time use patterns were defined by an individuals’ time spent on maintenance, subsistence and leisure activities each day. We analyzed the time use patterns of different population segments, such as gender, region, age, employment status, and income. Rural residents spend 2 h per day more on SA than urban residents. Five of the employment status categories; migrant workers, full-time students, retirees, the unemployed, and Home-makers, each have unique time schedules. Moreover, time use patterns vary greatly between the different age groups and different income levels. The relationships between the time spent on maintenance, subsistence, and leisure activities were analyzed. Time spent on subsistence activities each day were negatively correlated with time spent on maintenance and leisure activities. The time spent on maintenance activities was positively correlated with the time spent on leisure activities. The ratio of time spent on maintenance, subsistence and leisure activities in China is compared with that in Japan, America and New Zealand. A new term, Time Structure, was coined to describe the ratio of individual time spent on maintenance, subsistence and leisure activities. The time structure in China is 60:24:16 and differs from the structures found in the other countries examined.     

The Effects of Breastfeeding and Nutrition on Fecundability in Rural Bangladesh: A Hazards-Model Analysis

Data taken from the ‘Determinants of Natural Fertility’ study, Bangladesh, are used with multivariate hazard models to study variations in fecundability between women, especially the relationship between nutritional status, breastfeeding practices, and the monthly probability of conceiving. It is found that fecundability varies both between women of a given age and, for a particular woman, by age. The variation is related to four variables: separation, which affects coital frequency; age, which represents biological changes; lactation practices; and the duration of amenorrhoea. Nutrition above famine or starvation levels is not a significant determinant of fecundability. The most surprising finding is the effect of the pattern of breastfeeding on fecundability: as a menstruating woman begins to wean her child, her probability of conceiving increases as her serum prolactin, which inhibits ovulation, decreases. Thus, those menstruating women who are most likely to conceive are those who have completely weaned their infants in the very recent past.     

Modeling Quality-Adjusted Life Expectancy Loss Resulting from Tobacco use in the United States

Purpose  To describe the development of a model for estimating the effects of tobacco use upon Quality Adjusted Life Years (QALYs) and to estimate the impact of tobacco use on health outcomes for the United States (US) population using the model. Method  We obtained estimates of tobacco consumption from 6 years of the National Health Interview Survey (NHIS). In addition, NHIS data were used to impute the Quality of Well-Being (QWB) Scale using a new methodology known as QWBX1. The QWB places health status on a continuum ranging from death (0.0) to full functioning without symptoms (1.0). The method allows the adjustment of life expectancy for reduced quality of life associated with health conditions. NHIS data were matched to the National Death Index for 14,464 deaths occurring by December 31, 1997. The analysis is limited to adults between the ages of 18 and 70 years. Results  Quality of Well-Being scores were broken down by age and for six smoking categories: (1) non-smokers, (2) those who smoke 1–10 cigarettes per day, (3) 11–20 cigarettes per day, (4) 21–30 cigarettes per day, and (5) 31–40 cigarettes per day, and (6) 40 or greater cigarettes per day. There was a systematic relationship between current tobacco use and health-related quality of life at each point along the age spectrum and there was a clear and systematic separation of quality-adjusted life expectancy by number of cigarettes smoked per day. Teenagers who continue to smoke loose 3.5 QALYs between ages 18 and 70 in comparison to non-smokers. A greater portion in the loss in QALE is attributable to quality of life than to shorten life expectancy. Conclusions  The overall goal of Healthy People 2010 is to increase Years of Healthy Life (or QALE) in the United States. Each year, tobacco use results in hundreds of thousands of quality-adjusted life years lost. Combined models of morbidity and mortality incorporating a range of tobacco consumption levels are required to best represent the impact of tobacco use. Supported by a Grant 11RT-0243 from the Californian Tobacco Related Disease Research Program (TRDRP)     

An old balancing act: resources v. population

Population concern is found not only among modern man, but among primitive peoples and animal groups. Although some researchers object to extrapolating from animal behavior to human behavior, it is still an oft-observed fact that crowding produces fighting, territorial aggression, or other behaviors which disperse the population and relieve the pressures on food and other resources. Female chimpanzees bear offspring at 5-year intervals although they come into estrus yearly. This may be due to the ovulation suppression effects of lactation, which is lengthy among chimps. A similar repression gives humans respite from childbearing. Among primitive peoples similar population control mechanisms are at work. The Rendille camel herders in Kenya tried to limit population by insisting on monogamy and late marriage and killing boys born on Wednesday or younger ones after circumcision of the eldest brother. Among 96 births observed to the Netsilik Eskimos, an anthropologist noted that 38 female babies were left to die from exposure before becoming "people" in a naming ceremony. Cheyenne Indians limited population by insisting a woman should not have another child until her 1st is 10-years old. This required rigorous abstinence. Anthropologist Mary Douglas suggests a group will often define optimal population by perceived scarcity of things that are important to their society. The Pacific islanders of Tikopia strongly disapprove of families with more than 2 or 3 children. This limitation seems due to the limitation of cocoanuts. The Rendille limit population because of their desire to assure enough camels to go around. Researchers have followed with interest the 1st demographic transition of the Kung tribe of Africa. When they were hunter-gathers, women had high status because they provided at least half the food and births were 4-5 years apart because the nourishment level was so low pregnancy did not occur during lactation. Now that they have become farmers women's status has dropped and birthrates have increased. It will be interesting to see if this group undergoes a 2nd transition and starts to limit its population.     

Structural Change in Life Cycle Fertility During the Fertility Transition: France Before and After the Revolution of 1789

This paper explores the hypothesis that the fertility transition in France entailed a structural change in behaviour from natural to controlled fertility. We define the hypothesis in terms of an empirically estimable model of lifetime fertility. The model produces separate estimates of the three main proximate determinants: the hazard rate of conception for ovulating women, the timing of ovulation resumption after a birth, and permanent sterility. Fertility control is defined as responsiveness of the conception hazard to number of surviving children. We demonstrate key features of the model by simulated family histories. The historical application provides support for the transition hypothesis in the south of France, and mixed results for the north. We also find strong evidence of persistent couple-specific heterogeneity even after controlling for unobserved heterogeneity in fecundability. We suggest how future research might improve the model.     

Time use and leisure: Subjective and objective aspects

This paper utilizes data from the 1981 Canadian Time Use Pilot Study and from a small Halifax time-budget study to look at subjective and contextual dimensions of leisure for women and men. The Canadian study (n=2685) had information on the time spent in daily activities as well as on the settings and social contexts of those activities. The Halifax study included similar time-budget information on 60 married couples, but also incorporated subjective ratings of all diary events in terms of perceived work or leisure. Using subjective weightings from the Halifax study, estimates of subjective leisure were made for different categories of daily activity and for different Canadian population subgroups. Hypercodes were used to look at the effect of social roles on leisure time, and the AID procedure was used to analyze the contextual dimensions of leisure for men and women. The results show that objective activity and well as subjective leisure vary by population subgroup. Constraints to leisure include being female, being employed, having children, and, to some degree, being married. Of the contextual dimensions, subjective leisure was shown to be influenced primarily by type of objective activity. Location, time of day and day of the week also influenced leisure designations, but to a lesser extent. This study suggests the potential usefulness of subjective weightings of activities in order to gain a greater understanding of leisure patterns and participation.     

A field study of the effect of prebaiting on censusing by the capture-recapture method in a vole population

Summary Populations of the vole,Clethrionomys rufocanus, in a lowland woodlot of Hokkaido were studied for the presence of effects of prebaiting on censusing by the capture-recapture method. A grid of 121 live-traps, spaced 5 m apart, was laid out on each of two plots, one of which alone was prebaited three days long. Owing to very high densities and great trap-efficiency, sufficient and favourable samples could be available for statistical analysis, except the trend of delayed catch for young in sampling. The population on either plot, however, proved to be markedly variable in catchability of unmarked animals in the course of trapping; while the probability of recapture was counted as invariable on the average from day to day, the recapture frequency was different between juveniles, subadults and adults. Needless to say, the catchability was distinctly greater for marked voles than for unmarked ones, whether prebaited or not, through the trapping period, except that the first-day catchability for unmarked ones on the prebaited plot seems not to be significantly lower than that for marked ones. Consequently, it turns out that the prebaiting has almost never helped to eliminate the important bias induced by differential trap-response of marked and unmarked animals; its contribution is only that the catchability for unmarked ones is slightly higher on the part of the prebaited plot on earlier days of the period. In accordance with the heterogeneous catchability, the Γ-form distribution analogous to the geometric could be applied with thorough fitness to the capture frequency in order to estimate the whole populations. The fact that the estimates are reliable, being not at any rate underestimates, was further confirmed by the result of a follow-up work conducted by means of the removal method with wider trap-spacing which brought forth distinct underestimation chiefly referable to unexposure to traps of the partial populations. The subject of unexposure was discussed by laying stress on the relation between minimum range length and trap-spacing. Contribution from JIBP-PT No. 88, carried out by the grant from the expenditure of Education Department to the specific study on “Dynamics of Biosphere”.