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PubMed1995

A study of breastfeeding and the return of menses in Hoima District, Uganda.

The effect of breastfeeding on reestablishment of ovulation and fertility and on birth spacing are now well known. A study was conducted on lactational amenorrhoea (LAM) at 180 days in Hoima District, Uganda in order to understand whether and how LAM could be applied in fertility control and birth spacing. Since the introduction of supplementary food by Ugandan women does not replace or substitute for breastfeeding, a study was designed to determine if LAM was effective irrespective of supplementation of infant's diet. One hundred and fifty four mother/child pairs were entered into the study and 134 women completed the sixth month of the study. At the end of the period, eighty four women (62.7%) were amenorrhoeic of whom only 33 (39.3%) were exclusively breastfeeding and no woman had dropped out of the study because of pregnancy or the use of other family planning methods other than LAM. The study confirmed that LAM could be applicable in Uganda to the majority of the breastfeeding women (62.7%). It is expected that if health workers increase the intensity of breastfeeding support as well as the women's knowledge and motivation to use LAM for family planning, this would contribute to children's health as well as to birth spacing that is one of the major factors related to infant deaths. According to data from this study, the return of menses is irrespective of whether supplements have been introduced and their frequency.

Adolescent↗
PubMed1994

Drinking-water quality, sanitation, and breast-feeding: their interactive effects on infant health.

The promotion of proper infant feeding practices and the improvement of environmental sanitation have been two important strategies in the effort to reduce diarrhoeal morbidity among infants. Breast-feeding protects infants by decreasing their exposure to water- and foodborne pathogens and by improving their resistance to infection; good sanitation isolates faecal material from the human environment, reducing exposures to enteric pathogens. Taken together, breast-feeding and good sanitation form a set of sequential barriers that protect infants from diarrhoeal pathogens. As a result, breast-feeding may be most important if the sanitation barrier is not in place. This issue is explored using data from a prospective study of 2355 urban Filipino infants during the first 6 months of life. Longitudinal multivariate analyses are used to estimate the effects of full breast-feeding and mixed feeding on diarrhoeal disease at different levels of sanitation. Breast-feeding provides significant protection against diarrhoeal disease for infants in all environments. Administration of even small portions of contaminated water supplements to fully breast-fed infants nearly doubles their risk of diarrhoea. Mixed-fed and weaned infants consume much greater quantities of supplemental liquids, and as a result, the protective effect of full breast-feeding is greatest when drinking-water is contaminated. Similarly, full breast-feeding has stronger protective effects among infants living in crowded, highly contaminated settings.

Adult↗
PubMedDate not supplied

Breast-feeding and natural family planning.

The record of 50 postpartum women who intended to breast-feed for longer than 6 month were analyzed. Fifty percent of the women breast-feed longer than 12 month, and 50% resumed menses by 40 weeks after childbirth. Fifty-two women record of mucus and basal body temperature (BBT) fort at least 4 week before resumption of menses. Ovulation before menses while fully breast-feeding was probable in only one woman. Fifty percent of the first postpartum cycles had a short luteal phase Thirty-five women chose NFP to avoid pregnancy during the study period. Mucus and BBT proved to be a good marker of ovulation during postpartum cycles. Confidence in NFP during lactational amenorrhoea and first postpartum cycles in analyzed. Finally, research aimed at improving the teaching and use of NP for postpartum breast-feeding women is described.

Adult↗
PubMed1996

A study of the lactational amenorrhoea method of family planning in New Zealand women.

AIM: To evaluate the acceptance and efficacy of the lactational amenorrhoea method of family planning in breastfeeding clients attending clinics of the NZ Association of Natural Family Planning. METHODS: Mothers who were fully breastfeeding their babies, were amenorrhoeic and were early postpartum were offered for the purpose of family planning either lactational amenorrhoea method or the usual fertility awareness charting method. The clients who chose lactational amenorrhoea method were contacted at monthly intervals to check if they continued to meet the lactational amenorrhoea method criteria of fully breastfeeding and amenorrhoea. The fertility awareness group followed the normal practice of clinic visits for instruction until they became autonomous users. The status of both groups were assessed at 6 months postpartum when lactational amenorrhoea method users were advised to adopt another family planning method. RESULTS: Of 149 breastfeeding clients, 110 met the lactational amenorrhoea method criteria. Seventy chose lactational amenorrhoea method, the majority (56.7%) because of its simplicity. Thirty (48.6%) of initial lactational amenorrhoea method users were able to use the method for the full 6 months postpartum period. None of the women conceived while using lactational amenorrhoea method. CONCLUSION: For mothers who choose to fully breastfeed and who maintain a state of amenorrhoea lactational amenorrhoea method is an effective means of avoiding pregnancy during the first 6 months postpartum.

Adult↗
PubMed1998

[Advice on contraception for new mothers in Finland].

The abortion rates have increased slightly. In the statistics, the proportion of women having already given birth has become greater. New mothers should be informed of contraception. It should be emphasized that nursing is an effective method of contraception only if the mother has not had her menstruation yet and if the baby is totally breast-fed. Condom, pessary and copper coil are good contraceptives during nursing. New methods are being developed constantly, such as Nesteroni.

Adult↗
PubMed1998

[Lactation-induced amenorrhea as birth control method].

Improving access to quality care in family planning, a recent document of the World Health Organization, reviews the epidemiological and clinical evidence relevant to medical eligibility of well established contraceptive methods. Breastfeeding is widely regarded as unreliable for individual contraception. The document, however, argues that the lactational amenorrhoea method (LAM) is a safe and effective family planning method. Worldwide, LAM is the most important way of fertility regulation and its efficacy is confirmed in many studies, with a 2% risk of pregnancy in the first six months after birth. Taking into account certain well defined conditions (frequent feedings, no supplementary feeding before 4-6 months, method only to be used in the absence of menstruation), LAM can be relied on for contraceptive protection for up to 1 year post partum.

Amenorrhea↗
PubMed1987

Substrate and O2 fluxes during rest and exercise in a high-altitude-adapted animal, the llama.

Llamas were trained to exercise on a treadmill at graded speeds. O2 uptake values at rest, at modest exercise (ME, 0.58 m/s), and at heavy exercise (HE, 1.84 m/s) were 0.069, 0.297, and 0.594 ml O2 X kg-1 X s-1. Corresponding values for cardiac output were 1.64, 4.39, and 6.85 ml X kg-1 X s-1. Palmitate, glucose, and lactate replacement rates (Ra values) were determined at these varying work rates using a single-bolus injection of 14C- or 3H-labeled metabolites, two at a time. Ra values for palmitate, glucose, and lactate at rest were 6.2, 61.4, and 36.1 mumol X kg-1 X min-1, respectively. During ME, the Ra values for glucose and palmitate increased about twofold but showed no further increase when exercise intensity was increased about twofold. In contrast to these results, Ra values for lactate increased much more with increasing work rate. A combination of increased perfusion (increased cardiac output) and increased lactate availability (increased plasma concentration) could account for the lactate Ra data. During prolonged ME, the Ra for lactate decreased because lactate availability decreased; concurrently, both the plasma free fatty acid availability and the Ra values for palmitate greatly increased. Because O2 carrying capacity is low in the llama (as in all high-altitude-adapted mammals), a given level of exercise required exaggerated increases in cardiac output (and hence in perfusion rates of working muscles). As a result, the flux rates of palmitate, glucose, and lactate through the plasma compartment could readily account for O2 flux rates even at relatively high sustainable rates of exercise.

Acclimatization↗
PubMed1996

Lactate distribution and metabolism during and after anoxia in the turtle, Chrysemys picta bellii.

To determine the fate of lactate during and after prolonged anoxia, 14C-labeled lactate was injected into turtles after 2 h of a 6-h submergence at 20 degrees C. 14C activities of plasma and chamber water were tested at intervals during anoxia and also in expired air during 39 h of recovery. Partitioning of label in major body compartments [extracellular fluid (ECF), intracellular fluid (ICF), and shell] and 14C activity and glycogen in selected tissues (heart, liver, and muscle) were measured after anoxia (n = 7) and after recovery (n = 6). Shell 14C and [lactate] were extensively measured on six anoxic turtles. During anoxia all 14C remained in the animal indicating no urine production. At 6 h of anoxia 47% of recovered 14C, presumably still as lactate, was in the ECF, 27% in the ICF, and 30% in the shell. During recovery, plasma [lactate] fell from 35 to 5 meq, but surrounding water and expired air accounted for only 9 and 8%, respectively, of recovered label. The ICF portion grew to 41%, associated with a recovery in tissue glycogen. The shell still had 22% of total label. We conclude that, during recovery from anoxia, lactate is predominantly resynthesized to glycogen, and only a small fraction is directly oxidized. During anoxia, however, lactate is widely distributed in the body, and a surprisingly large and functionally significant fraction resides in the shell.

Animals↗
PubMed1987

Oxygen consumption, lactate accumulation, and sympathetic response during prolonged exercise under hypoxia.

Six men (33 +/- 3 years old) performed 1 h ergocycle exercise (60% VO2 max) at sea level and at a simulated altitude of 3000 m. A similar relative exercise intensity corresponded to a lower absolute work load (139 +/- 4 W) in hypoxic than normoxic (163 +/- 4 W) conditions. Lower oxygen uptake (VO2) with no change in ventilation (VE), respiratory exchange ratio (R), and heart rate (Hr) were observed during exercise under hypoxia compared to normoxia. A slow rise in VO2, after the initial 5 min exercise, was observed in normoxic (+ 230 ml/min) as well as in hypoxic (250 ml/min) conditions that might be, in part, related to oxidative removal of blood lactate. Peak blood lactate concentration reached at 30 min of exercise was similar in normoxia (4.5 +/- 0.4) and in hypoxia (4.7 +/- 0.5). However, while the lactate level decreased during exercise at sea level, it remained elevated throughout exercise in altitude. Blood lactate concentration measured at the end of exercise was significantly (P less than 0.05) higher in hypoxic (4.4 +/- 0.3) than in normoxic (3.2 +/- 0.4) conditions. Catecholamine response to exercise was similar in both conditions. We conclude that during prolonged exercise at a given relative work load, hypoxia does not affect cardiorespiratory and sympathetic responses but tends to increase blood lactate accumulation. Higher blood lactate concentrations during hypoxic exercise seems to reflect alterations in the removal of blood lactate rather than changes in glycolytic flux.

Adult↗
PubMed1981

The effect of lactate on the radiation response of CHO-K1 cells in culture.

The radiobiological effect of lactate is described. Prolonged incubation of CHO-K1 cells over a wide range of lactate concentrations sensitized them to subsequent irradiation. Survival curves indicated that the size of the shoulder was reduced. Short treatment times resulted in a radioprotective effect and an increase in the survival curve slope. Lactate levels used were within physiological limits and are therefore discussed in relation to their possible implications in radiobiology and radiotherapy.

Animals↗
PubMed1997

The maximal lactate steady state in elite endurance athletes.

The upper limit of blood lactate resulting in a lactate steady state during prolonged exercise is called the maximal lactate steady state (MLSS). The purpose of this study was to investigate the lactate response to steady-state exercise during a field test in elite endurance athletes. Plasma lactate levels were assessed in 13 elite triathletes and 13 elite cyclists (mean +/- SD; age 23.7 +/- 5.1 yr; HT 180.2 +/- 6.3 cm; WT 70.3 +/- 5.9 kg; VO2 max 68 +/- 3.7 ml/min/kg) during a 40 km-long time trial on a bicycle (4 km course x 10 laps). The steady state was demonstrated by monitoring the heart rate and timing every course run. The lactate levels were expected to correspond to MLSS. The mean level of lactate during the time trial was 7.4 +/- 2.5 mmol/l. Five athletes maintained plasma lactate levels which exceeded 10 mmol/l or more for almost 1 h. The large value of individual variability was conspicuous (range 3.2-12.2 mmol/l). These values exceeded all previous reported levels for MLSS from other investigators. Our observations are important in sport medical practice since the different lactate responses to exercise are used as parameters in training management.

Adolescent↗
PubMed1998

Psychomotor performance during prolonged exercise above and below the blood lactate threshold.

Previous investigations from this laboratory have demonstrated that during graded exercise with exercise intensities increasing every 3 min until exhaustion the multiple choice reaction time (RT) decreased until the intensity exceeded the lactate threshold (LT) by approximately 25%, and then rapidly increased. The aim of this study was to follow up changes in RT during prolonged exercise at constant intensities above and below LT and to relate these changes to changes in venous blood lactate [La-]b, and plasma catecholamine [CA]pl concentration responses to the exercise. For this purpose eight young soccer players exercised for 20-min on a cycle ergometer at 10% above LT, and nine exercised for 60 min at an intensity 30% below LT. During both tests RT, heart rate (HR), as well as [La-]b, and [CA]pl were measured. Above LT, RT decreased from the 5th min until the end of exercise, whilst HR, [La-]b, and [CA]pl increased progressively. Significant inverse correlations were ascertained between RT and plasma adrenaline (r = -0.651) and noradrenaline concentrations (r = -0.678). During exercise below LT, RT decreased up to approximately 40 min, then it reached a nadir, and stabilized at this level. This was accompanied by only small changes in [La-]b and [CA]pl. The present findings would indicate that young athletes are able to maintain for a relatively long time, or even increase, their psychomotor performance during endurance exercise both below and above the LT.

Adult↗