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PubMed1993

Factors influencing infant mortality in Vietnam.

Selected determinants of overall infant mortality in Vietnam were examined using data from the 1988 Vietnam Demographic and Health Survey, and factors underlying neonatal and post-neonatal mortality were also compared. Effects of community development characteristics, including health care, were studied by logistic regression analysis in a subsample of rural children from the 1990 Vietnam Accessibility of Contraceptives Survey. Infant neonatal and post-neonatal mortality rates showed comparable distributions by birth order, maternal age, pregnancy intervals, mother's education and urban-rural residence. Rates were highest among first order births, births after an interval of less than 12 months, births to illiterate mothers and to those aged under 21 or over 35 years of age. Logistic regression analysis showed that the most significant predictor of infant mortality was residence in a province where overall infant mortality was over 40 per 1000 live births. In the rural subsample, availability of public transport was the most persistent community development predictor of infant mortality. Reasons for the low infant mortality rates in Vietnam compared to countries with similar levels of economic development are discussed.

Adolescent↗
PubMed2004

Breeding season in female cats acclimated under a natural photoperiod and interval until puberty.

The breeding season was investigated in 174 female cats that were acclimated under a natural photoperiod, and determined the interval between birth and initial estrus (puberty) was determined in 125 cats. Although the breeding season differed noticeably among individual animals, the mean was 180.4 +/- 3.0 (SE) days between the end of January and the end of July. The interval between birth and first estrus ranged from 181 to 560 days, with a mean of 345.0 +/- 0.9 days. With respect to month of birth, the mean interval was 343.0 +/- 9.5 days in cats born between March and June. Among cats that were born between July and October, the mean intervals were 242.0 +/- 6.3 days in cats that exhibited estrus the year after birth and 519.2 +/- 5.8 days in those that exhibited estrus 2 years after birth.

Animals↗
PubMed1991

Risk factors for female breast cancer. A hospital-based case-control study in Madras, India.

Five hundred and thirty-one histologically confirmed breast carcinoma cases examined from 1983 to 1986 inclusive at the Cancer Institute (WIA), Madras, India, were matched for age, socioeconomic class and menopausal status with an equal number of controls. Cancer patients without diseases in breast, gynaecological organs or endocrine glands were used as controls. Risk factors for breast cancer were analyzed separately in the premenopausal and the postmenopausal groups. In neither group was there significant association between age at menarche and breast cancer risk. Single women had higher risk than married women. Nulliparity was found to be a risk factor in premenopausal women only. The relative risk increased with age at marriage and age at first birth. A three-fold risk was noted in both pre- and postmenopausal groups when the interval between age at first birth and menarche was more than 12 years and also in women who attained menopause between the age of 44-49.

Age Factors↗
PubMed1982

Secular change in birthweight of Asian babies born in Birmingham.

We have studied changes in the birthweight of Asian babies born alive at this hospital between 1968 and 1978. In 1978 Pakistani babies were 139 g heavier but Indian babies only 25 g heavier than 10 years earlier. Contributing to these changes were significantly fewer short mothers and primiparae among Pakistanis, and non-significant increases in gestational age and intrauterine growth (that is, weight centile after allowing for gestational age, parity, and maternal height). Among Indians there were significant increases in maternal height and gestational age, but parity was reduced and intrauterine growth did not increase. In both groups there were fewer teenage mothers, but whereas among Pakinstanis birth intervals of less than one year were less common, there was no such reduction among Indian mothers. The secular change suggests that genetic factors are unlikely to be the major reason why Pakistani babies born in Birmingham are lighter than European babies, and that environmental factors play an important role. Efforts to increase birthweight need to consider both the mothers' physical environment during pregnancy and prepregnancy factors influencing growth in childhood, age at first pregnancy, and birth interval. The study shows a need to describe an 'Asian' population with details of their sub-ethnic structure. The sub-ethnic and secular differences further suggest that a single 'Asian' standard for birthweight and intrauterine growth may be inappropriate; the use of international reference data with which all infants may be compared is preferable.

Adolescent↗
PubMed1975

Effects of electrical stimulation of the neurohypophysis on labour in the rat.

Labour was studied in 69 primiparous and multiparous rats by continuous observation and by the recording of intra-uterine activity. The effect of electrical stimulation of the neurohypophysis with stimulation parameters selected to create a pulsatile release of oxytocin was investigated. Stimulation was applied to the neurohypophysis through chronically implanted electrodes every 5 min, in 45 min sessions, from noon on Day 21 of gestation and at 3 h intervals thereafter. Electrical stimulation successfully promoted (or induced) the onset and facilitated the course of labour. Stimulation at 12.00 h on Day 21, or at a subsequent stimulation session 3, 6, 9 or more hours later, promoted an immediate increase in the frequency and amplitude of uterine contractions. Overt signs of abdominal straining followed within 5-30 min and the first pup was delivered shortly thereafter. These 'induced' deliveries were almost identical to those displayed by control rats; labour continued to completion despite the termination of the stimulation session after 45 min. By contrast, one third of the stimulated animals displayed an interrupted pattern of labour in which events virtually ceased for 30-60 min when stimulation was terminated. Stimulation, however, only advanced labour by 1-2 h in relation to control animals; this was not statistically significant. Stimulation accelerated the delivery of the first 5 pups in each litter. In both stimulated and control animals, the birth intervals declined over these first few deliveries to reach the lowest values of 5-6 min throughout the remainder of labour. The most common litter size was 12 pups. The distribution of labour on Day 21 and 22 was bimodal. Seventy per cent of the animals gave birth between 12.00 and 18.00 h on Day 21, a few gave birth during the following night and the remainder formed a second peak on Day 22. All litters of less than 6 pups were born during this later period. The implications of these results in the context of spontaneous labour are discussed. We conclude that endogenous oxytocin (with perhaps other neurohypophysial hormones) released in pulses of 1-3 mu. every 5 min can promote a pattern of labour on Day 21 of gestation that is almost indistinguishable from that which occurs naturally.

Animals↗
PubMed1979

Labor supply behavior of prospective and new mothers.

Utilizing unique data generated from the National Longitudinal Surveys of Young Women, this paper examines the labor force participation of young mothers in the months immediately preceding and following the birth of the first child. Labor supply behavior at this point in the life cycle is described in greater detail than has hitherto been available. In addition, we analyze the independent effect of several factors of interest on the probability that a young woman will be in the labor force during various intervals surrounding the first birth.

Adolescent↗
PubMed2003

Fertility of mice following receipt of ovaries slow cooled in dimethyl sulphoxide or ethylene glycol is largely independent of cryopreservation equilibration time and temperature.

Cryopreservation procedures generally depend on both the cryoprotectant used and the equilibration conditions to which the material is exposed. The aim of the present study was to examine the effect of cryoprotectants (dimethyl sulphoxide (DMSO) and ethylene glycol (EG)) and equilibration conditions (0, 30 or 120 min at 0 degrees C or 120 min at room temperature) on the fertility of mice receiving cryopreserved mouse ovaries. The study compared the fertility of cryopreserved Day 14 mouse pup ovaries following grafting to adult recipient mice for 4 months. There was no effect of the cryoprotectant or equilibration condition used on the interval to the first plugging/mating or on the interval to the birth of the first litter, the size of litters, the number of litters produced or the total number of offspring produced. Despite this, when compared with control females (untreated, sham and fresh transplant) the cryopreservation and transplantation procedures delayed fertility. However, the size of litters was equivalent for all cryopreserved and control groups (P > 0.05). The results show that, for the equilibration conditions examined, DMSO and EG are equally efficient cryoprotective agents for mouse ovarian tissue.

Animals↗
PubMed1983

Auditory brainstem response in neonates during the first 48 hours after birth.

Auditory brainstem response (ABR) has been recorded in 20 neonates at three different time intervals during the first 48 hours after birth. The first recording was performed about 15 min after delivery, when the babies were in their first period of postnatal reactivity. During this period, we were unable to obtain reliable ABR data. During the second and third ABR test performed 2 and 48 hours after birth the babies revealed gradually better responses. Data from these recordings suggest no significant change in middle ear function during the time interval between 2 and 48 hours after birth. Observations of amplitude ratio wave V/wave I are presented. Finally, reservations regarding the interpretation of the results are discussed.

Audiometry↗
PubMedDate not supplied

Breast feeding patterns in an urban resettlement colony of Delhi.

Studies on duration and patterns of breast feeding based on recall may lead to a bias about the exact feeding status. The present study was designed to overcome this bias using the 'current status analysis method'. Mothers of 650 infants from 0 to 12 months of age attending a Health Centre were interviewed about the current feeding patterns of the infants and other socioeconomic variables. Month-wise prevalence of feeding patterns was determined. It was observed that breast feeding was maintained at a high level (more than 90%) throughout infancy while exclusive breast feeding showed a rapid decline. At 1 month, 74% and at 4 months, 46% of infants were exclusively breast-fed. The median duration of exclusive breast feeding was 3.83 months. Mothers with lesser education and lower family income were more likely to exclusively breast feed (p < 0.05). The time interval between birth and first breast feed was 24-48 hours in most (48.9%) of the infants. Majority (76.9%) of the infants received pre-lacteal feeds. Hospital-born infants received their first feed earlier and were less likely to receive pre-lacteal feeds as compared to those born at home (p < 0.001). Thus, the practice of exclusive breast feeding has to be promoted amongst pregnant and lactating mothers by health personnel. Also knowledge regarding infant feeding has to be imparted in schools and colleges.

Breast Feeding↗
PubMed2003

Retained second twins in Enugu, Nigeria.

OBJECTIVES: To review our experience with retained second twin in Enugu, Nigeria, over a 10-year period. METHODS: The second twin is retained when a delay of 30 min occurs after the delivery of the first twin. The case notes and records of all twin deliveries at the University of Nigeria Teaching hospital Enugu between January 1991 and December 2000 were retrieved and analyzed. RESULTS: Retained second twin occurred in 1/6 twin deliveries with a resultant perinatal mortality rate of 288.5 per 1000 deliveries which was 1.7 times that of first twin. Malpresentation (54%) and uterine atony (39%) were the principal causes of retained second twins. The place of delivery of the first twin, prolonged birth intervals, oxytocin augmentation of labor and breech extraction affected perinatal outcome. CONCLUSIONS: Early recourse to vacuum extraction and cesarean deliveries of retained second twin, effective health education and adequate supervision of primary health care facilities are advocated to reduce this preventable condition.

Adolescent↗
PubMed1981

Effects of forced exercise during gestation on farrowing and weaning performance of swine.

Forty-three gilts and 24 sows were tethered throughout gestation, and one-half were forced to walk on a treadmill 15 min daily 5 days a week. Exercised and nonexercised dams farrowed 10.0 and 10.2 pigs (P greater than .05) and weaned 8.1 and 7.9 (P greater than .05), respectively. Birth weight of pigs born alive from exercised and nonexercised dams averaged 1.6 and 1.5 kg (P greater than .05); weaning weights were 8.5 and 8.2 kg (P greater than .05), respectively. Sows farrowed 12% more pigs (P less than .05) than gilts and weaned 17% more pigs (P less than .05) that were 12% heavier at birth (P less than .01) than those of gilts. Forced exercise did not improve (P greater than .05) reproductive performance as measured by numbers of pigs farrowed and weaned or by birth and weaning weights. Mean length of gestation was not significantly affected by age of dam or exercise treatment. The interval between birth of first and birth of last pig per litter averaged 154 and 151 min (P greater than .05) for exercised gilts and sows, respectively, and 170 and 161 min (P greater than .05) for those not exercised.

Animals↗
PubMed2006

Breast feeding patterns in a military hospital.

OBJECTIVE: To determine the status of breast feeding, exclusive breast feeding and other feeding patterns in infants upto 12 months age. DESIGN: Cross- sectional study. PLACE AND DURATION OF STUDY: Paediatrics Department and Immunization Center, Combined Military Hospital, Multan, from October 2004 to March 2005. SUBJECTS AND METHODS: This study was based on "current status analysis method" to eliminate the bias of recall method used in most previous studies. Mothers of 650 infants from 0-12 months of age, attending immunization centre and paediatrics OPD, were interviewed about current feeding patterns and other socioeconomic variables. They were divided in three groups depending upon their monthly income. Living conditions matched with monthly income status in all groups. Month-wise distribution of feeding pattern was determined. Analysis was made about the effect of education of mothers, family income, place and mode of delivery, gender of the baby on exclusive breast feeding, duration of breast feeding and initiation of breast feeding. Statistical analysis of the results was made by application of Parson's Chi-square test. RESULTS: Breast feeding was maintained at high level (more than 88%) throughout infancy. Exclusive breast feeding was also maintained at quite high level (66%) till 4 month age. But later there was a sharp decline to 16% at six months of age. The median duration of exclusive breast feeding was 3 months. Mothers with lesser education and lower family income were more likely to exclusively breast feed (p < 0.001). The time interval between birth and first feed observed was quite desirable (less than 3 hours) in most cases. Only 14% infants received pre-lacteal feeds (ghutti, honey, water etc.), while majority of them (59%) received breast milk. Formula milk was first feed in only 25% cases. Breast milk as first and early feed was observed more in babies born by normal delivery in hospital (p < 0.001). CONCLUSION: Status of breast feeding, exclusive breast feeding and other feeding practices was quite encouraging and desirable in this study. The factors responsible for these results are comprehensive, free and readily available medical facilities including motivational and preventive services provided to women and children in military hospitals. However, there is still need to improve the figures to achieve internationally set goals.

Breast Feeding↗
PubMed1997

Length of delay to birth of a second litter in dwarf hamsters (Phodopus): evidence for post-implantation embryonic diapause.

In Phodopus, all first litters are born after an 18 (or 19) day gestation. Birth of subsequent litters conceived during a postpartum estrus is routinely, but not always, delayed beyond 18 days. With an interval from first mating to birth of a second litter of as little as 36 days, Phodopus have the most compressed reproductive cycle of any eutherian mammal. Although pups of the Siberian hamster P. sungorus gain thermal independence from maternal care faster than pups of the Djungarian hamster P. campbelli, no species difference in the extent of delay to second litters was found. However, poor growth of first litter pups as a result of unintentional limitation of water bottle access increased delays before birth of a second litter in P. sungorus. Weight of pups in the first litter was a good predictor of the length of delay. In P. campbelli, females with large pups early in lactation were the only ones to deliver a second litter without delay, and short delays enhanced weaning weights for pups in the first litter. Patterns in P. sungorus were similar. The timing of the delay in second litters was investigated in P. campbelli. Delayed implantation during second pregnancies was common. Postimplantation embryonic diapause occurred in 43% of females following unilateral ovariohysterectomy on day 8 of a first pregnancy. As pup growth curves also implicated a postimplantation embryonic diapause, Phodopus may be the only known mammalian genus outside the order Chiroptera in which postimplantation diapause can occur.

Animals↗
PubMed2003

Interpregnancy interval and risk of preterm birth and neonatal death: retrospective cohort study.

OBJECTIVE: To determine whether a short interval between pregnancies is an independent risk factor for adverse obstetric outcome. DESIGN: Retrospective cohort study. SETTING: Scotland. SUBJECTS: 89 143 women having second births in 1992-8 who conceived within five years of their first birth. MAIN OUTCOME MEASURES: Intrauterine growth restriction (birth weight less than the 5th centile for gestational age), extremely preterm birth (24-32 weeks), moderately preterm birth (33-36 weeks), and perinatal death. RESULTS: Women whose subsequent interpregnancy interval was less than six months were more likely than other women to have had a first birth complicated by intrauterine growth restriction (odds ratio 1.3, 95% confidence interval 1.1 to 1.5), extremely preterm birth (4.1, 3.2 to 5.3), moderately preterm birth (1.5, 1.3 to 1.7), or perinatal death (24.4, 18.9 to 31.5). They were also shorter, less likely to be married, and more likely to be aged less than 20 years at the time of the second birth, to smoke, and to live in an area of high socioeconomic deprivation. When the outcome of the second birth was analysed in relation to the preceding interpregnancy interval and the analysis confined to women whose first birth was a term live birth (n = 69 055), no significant association occurred (adjusted for age, marital status, height, socioeconomic deprivation, smoking, previous birth weight vigesimal, and previous caesarean delivery) between interpregnancy interval and intrauterine growth restriction or stillbirth. However, a short interpregnancy interval (< 6 months) was an independent risk factor for extremely preterm birth (adjusted odds ratio 2.2, 1.3 to 3.6), moderately preterm birth (1.6, 1.3 to 2.0), and neonatal death unrelated to congenital abnormality (3.6, 1.2 to 10.7). The adjusted attributable fractions for these associations were 6.1%, 3.9%, and 13.8%. The associations were very similar when the analysis was confined to married non-smokers aged 25 and above. CONCLUSIONS: A short interpregnancy interval is an independent risk factor for preterm delivery and neonatal death in the second birth.

Birth Intervals↗
PubMedDate not supplied

Premarital childbearing in northwest Kenya: challenging the concept of illegitimacy.

A number of African countries, including Kenya, have experienced a marked rise in births among unmarried women. In Western countries, reproduction outside of marriage is assumed to be illegitimate and a social problem. One hypothesis used to explain the increasing incidence of premarital fertility in Africa is a breakdown of traditional social controls by the extended family over the sexual behavior of adolescents. A competing hypothesis suggests that unmarried women use sexual relations to achieve goals such as marriage. Among Turkana pastoralists of northwest Kenya, we find a pattern of premarital birth that fits either hypothesis only loosely. Premarital fertility among the Turkana is both widespread and culturally acceptable, with over 30 per cent of women having at least one child prior to marriage. Although women with premarital births initiate childbearing on average one year earlier than women with only marital births, women's marital status does not influence the length of the interval between first and second births. Marriage among the Turkana is not a social trigger for the onset and continuation of reproduction or a means to legitimate reproduction. Marital status of the parents simply determines the custody of a child. In a premarital birth, the father pays a set fee to the mother's family, and the custody of the child remains permanently with the mother's family. If the parents later marry, the father must purchase custody of the child by another fee at that time. Since the Turkana have experienced few effects of modernization, the existence of such a practice suggests that cultural factors must be taken into account before assessing premarital fertility in Africa as a social problem.

Adolescent↗
PubMed1983

Age at any birth and breast cancer risk.

In an effort to assess the relative importance of age at first birth, age at subsequent births, and total parity to the occurrence of breast cancer, reproductive data from 4,225 women with breast cancer and 12,307 hospitalized women without breast cancer were analyzed by a multiple logistic regression model. Age at first birth was confirmed to be the most important reproductive risk indicator; it was associated with a 3.5% increase of relative risk for every year of increase in age at first birth (the 95% confidence interval of this estimate was 2.3 to 4.7% increase per year). However, age at any birth after the first was also an independent and statistically significant risk indicator; it was associated with a 0.9% increase of relative risk for every year of increase in age at any (and every) birth (the 95% confidence interval of this estimate was 0.4 to 1.5% increase per year). There is evidence that the age of approximately 35 years represents for every birth a critical point; before this age any full-term pregnancy confers some degree of protection; after this age any full-term pregnancy appears to be associated with increase in breast cancer risk. The effect of parity is determined by the age of occurrence of the component pregnancies. While most pregnancies occur under the age of 35, the distribution varies from population to population, and this may account for the differences between populations in whether or not a protective effect is seen for births after the first, and if it is seen, its extent.

Adolescent↗