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At least 19 recordsLinked to original sources
PubMed1978

Birth interval study in a culturally stable urban population.

Five hundred women were interviewed within 2 days of delivery to examine indigenous birth spacing among the urban and rural population of Ife township. The crude birth interval was between 30 and 40 months due mainly to cultural attitudes towards lactation and sexual abstinence. The women studied possessed considerable knowledge of Western contraceptive methods, but they rejected them. The possible cause of this rejection is examined and solutions to the problem are suggested.

Birth Rate↗
PubMed1979

Gestation and inter-birth intervals in the owl monkey (Aotus trivirgatus griseimembra).

A single, timed mating indicated a gestation period of 133 days for Aotus trivirgatus griseimembra. This figure is confirmed by approximate correspondence with minimum inter-birth intervals, results from radioimmunoassay of urinary oestrogens during pregnancy, and general agreement with a logarithmic plot of gestation period against body weight for simian primates. Birth data indicate that owl monkey females in present colonies in captivity breed throughout the year and will, on average, produce 3 infants every 2 years. There is no evidence of a characteristic post-partum oestrus.

Animals↗
PubMed1979

Seasonal migration and seasonal variation in fecundability: effects on birth rates and birth intervals.

Seasonal patterns in conception rates have been documented in several recent studies. In this paper, a mathematical model of the reproductive process is developed through which the impact of such variation in conception rates is assessed. It is found that the effect on fertility can be quite substantial, but that the birth rate when seasonal variation is occurring is approximated well by the birth rate calculated when conception rates are constant at their mean. These results indicate that further documentation of seasonality in conception rates and exploration of the causes of these patterns and their change is an important area for demographic research.

Birth Rate↗
PubMed1976

Lactation--the central control of reproduction.

We are used to thinking of lactation as a consequence of reproduction but we tend to forget that, in many marsupials and placental mammals, lactation serves the equally important function of spacing-out the interval between successive births. In primitive human communities, the duration of the birth interval was all-important for the survival of the young, and lactational amenorrhoea lasting up to two years was nature's most effective form of contraception. Today, particularly in urban areas, lactational amenorrhoea is short, even in those women who still breast-feed their babies, and this has been one of the major factors responsible for the recent rapid growth of the human population. There is still much speculation about the way in which lactation and nutritional status may act in concert to suppress reproductive activity. Afferent stimuli from the nipple are an essential component of the reflex and it is possible that, in addition to a generalized central inhibition, they may initiate secretory surges of prolactin that have a direct inhibitory action on the ovary itself. The evidence for these various mechanisms of action is discussed.

Amenorrhea↗
PubMed1976

Results of the Inter-American Investigations of Mortality relating to reproduction.

Maternal age and parity, according to the findings of the Inter-American Investigation of Mortality in Childhood, have a direct relationship to the health and survival of the infant. Among the results of this broad undertaking are data suggesting that babies born close in succession, especially within large families and as birth order ascends, are at greater risk of dying. Also, the offspring's future is increasingly threatened as the mother's age tends toward the extremes of the childbearing years. Compromise of the mother's health, in turn, was indicated in the earlier Investigation, a study of deaths in adults, which revealed unexpectedly high maternal mortality in the Latin American cities that it covered. Immaturity, or low birthweight, and malnutrition emerged as the two major underlying or associated causes of death in the Latin American projects of the Inter-American Investigation of Mortality in Childhood. Despite the marked variations in the data available from the different areas, there appeared to be some correlation between these two indicators of deficits in growth and development. Mortality due to immaturity was especially high for babies of young mothers, with increases occurring as the birth order rose. Not only are the risks greater for mothers having low-weight babies when they are young (under 20), but they increase even more with the second, third, and fourth products when the birth intervals become shorter. Maternal age, birth order, and birthweight are factors that must be considered in combination in the programming of protective health measures.

Adolescent↗
PubMed1978

Interpregnancy interval. Association with birth weight, stillbirth, and neonatal death.

Pairs of first and second births and pairs of second and third births to the same Norwegian mothers were studied to determine the association between interpregnancy interval and birth weight, stillbirth, and neonatal death. Use of the pair approach provides one birth which could possibly have been affected by the length of the interval and one birth which could not. The association of interval and birth weight for births which precede an interval is found to be equivalent to that for births which follow an interval. The data on stillbirth are compatible with higher rates at long intervals while the data on neonatal death are consistent with higher rates at short intervals. However, we conclude that manipulation of the interval between pregnancies is unlikely to have any marked, direct, beneficial effect on outcome of pregnancy.

Birth Order↗
PubMed1979

Machakos Project Studies: agents affecting health of mother and child in a rural area of Kenya. XVI. The outcome of pregnancy.

The outcome of pregnancy of all women belonging to the study population of the Machakos project studies who delivered during 1975 and 1976 is presented. The birth-rate was 43.0 per 1,000 population per year, the fertility rate was 235 per 1,000 women 15--44 years of age per year. Unexpected low mortality rates were found; stillbirths, neonatal and infant death rates were respectively 29.8 per 1,000 total births and 22.5 and 50.0 per 1,000 live births. One maternal death occurred among the 2,223 deliveries. Maternal age of less than 25 and over 34 years, a history of previous perinatal death and breech delivery were associated with higher perinatal mortality. Parity, marital status, birth-interval and maternal height were not associated with a difference in outcome of pregnancy. The stillbirth rate among the children born in hospital (26.4%) was 4.4% compared with 2.4% among the children born at home, neonatal and infant death rates were the same. Half of all perinatal deaths were caused by either prematurity or birth trauma, 75% of all infant deaths after the first week of life were caused by infections.

Adolescent↗
PubMed1979

Nutritional status of light-for-date infants at birth and its influence on early postnatal growth.

The ponderal index (PI) (g/cm3 X 100) was used to define the state of nutrition at birth of 47 light-for-date (LFD) term infants and to determine how intrauterine undernutrition influences growth during the first 6 months of postnatal life, at four age intervals: birth--4, 5--8, 9--12, 13--26 weeks. With the exception of one baby, each PI was less than 50th centile on the Miller and Hassanein standards: in 24 (51%) babies the PI was less than 3rd centile. This suggests that, generally, LFD infants are underweight for length, and by inference, are likely to have experienced intrauterine undernutrition. In the first month the 24 'wasted' infants (PI less than 3rd centile) gained more rapidly in weight, and grew more quickly in head circumference and length than the 16 'nonwasted' infants (PI greater than 10th centile). Thereafter growth rates were similar. With the exception of weight in the 'nonwasted' infants during the first month, rates of growth (weight, length, and head circumference) in both groups of babies in each of the 3 months after birth were greater than in normal infants. The first 3 months after birth can therefore be defined as the period of 'catch-up' growth in LFD term infants.

Body Height↗
PubMed1977

Birth order and intellectual development: the confluence model in the light of cross-cultural evidence.

For Israeli eighth-grade students of Asian-African origin, achievement decreases as a function of birth order in small families and increases as a function of birth order in large families. This finding cannot be accounted for by differences in developmental rate or size of birth intervals. It can be accounted for by considering the effect of external influences, such as schooling, on intellectual development.

Achievement↗
PubMedDate not supplied

The nutritionally at risk child. Part 2 : study of factors pertinent to the child, siblings or mother.

Several high risk factors were evaluated in an attempt to determine the Egyptian children who are more prone to become malnourished. The study included 110 children with energy protein malnutrition and 98 normal children. Their ages were between 4 months and 3 years. Among the factors investigated, the 2nd 6 months of life was found to be the most critical for nutritional deficiency. Presence of previous siblings with malnutrition, presence of more than 2 sibling deaths and presence of history of severe diarrhoea with dehydration were significantly related to the nutritional status of children. Twinning, birth order and birth interval showed some relation to malnutrition but were not statistically significant. The sex of the child and maternal weight did not influence the nutritional state of children. However, these low-socialclass children were found to be mostly (92.8%) breast fed.

Age Factors↗
PubMed1977

Age at puberty in relation to age at marriage and parenthood: a national longitudinal study.

A longitudinal study of a British cohort has collected information on puberty, judged by menarcheal age for the girls and the pubertal stage of the boys at age 14 3/4. This information has now been related to the ages at which these young people married and became parents. For the young men there was evidence of a direct relationship between degree of sexual maturity at age 14 3/4 and their ages at entry into marriage and fatherhood. For the young women, if pregnancy did not intervene between menarche and marriage, there was evidence of a direct relationship between menarcheal age and marriage age. But there was no evidence that these earlier-maturing young women became mothers at earlier ages than later maturers. This arose through the later-maturing young women having shorter first birth intervals than the earlier maturers. Premarital conceptions were also more prevalent amongst the later maturers.

Aging↗