Browsing by Author "PEREZ, A"

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    CLINICAL-STUDY OF THE LACTATIONAL AMENORRHEA METHOD FOR FAMILY-PLANNING
    (1992) PEREZ, A; LABBOK, MH; QUEENAN, JT
    The effect of breastfeeding on fertility is well known; however, its use as a method of family planning was, until recently, untested. In 1988, the Bellagio Consensus Conference proposed guidelines that became the basis for a method of family planning called the lactational amenorrhoea method (LAM). The principle of LAM is that a woman who continues to fully or nearly fully breastfeed her infant and who remains amenorrhoeic during the first 6 months postpartum is protected from pregnancy during that time. We have assessed this method in the context of a breastfeeding support intervention study of 422 middle-class women in urban Santiago, Chile. The cumulative 6-month life-table pregnancy rate was 0.45% among women who relied on LAM as their only family planning method (1 woman pregnant in month 6). The findings indicate that LAM, with its high acceptance and efficacy, is a viable method of family planning and can safely serve as an introductory method for breastfeeding women.
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    HUMAN LACTATIONAL RESPONSE TO ORAL THYROTROPIN RELEASING HORMONE
    (1976) TYSON, JE; PEREZ, A; ZANARTU, J
    Several studies were designed to evaluate the effect of oral TRH [thyrotropin releasing hormone] on prolactin (PRL) secretion and mammary function in nursing women. Initially efficacy was studied in nursing women following 5 mg TRH. PRL levels rose to a mean maximum of 46.3 ng/ml above baseline at 60 min. Plasma TSH also increased from a mean baseline of 2.6 to 17.6 .mu.U/ml at 180 min. No changes were observed following placebo. In order to observe the long term effects of oral TRH, 2 groups of women in full nursing were studied. Beginning on day 29 postpartum, either 5 mg TRH or placebo were taken twice daily for 4 wk. No chronic elevations were observed in maternal PRL and TSH or in infant TSH before or after 1 mo. of either regimen. Milk composition expressed in terms of per cent protein and per cent fat did not differ between the groups. Weekly gonadotropin levels were also similar as were infant weight gain and growth. In a group of women with lactational insufficiency receiving 5-20 mg TRH twice daily for 5 days, basal PRL concentrations markedly increased. While changes in milk composition were not significant, fat percentages increased slightly and protein percentages declined. Breast engorgement and milk letdown increased and full nursing was restored. While the oral TRH used in fully nursing women had no demonstrable effect on mammary function, it may prove useful in those women with lactational insufficiency. Because 2 women developed iatrogenic hyperthyroidism following 40 mg oral TRH twice daily, care must be exercised in determining the dosage to be employed.
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    KAPPA-OPIATE-INDUCED DIURESIS AND CHANGES IN BLOOD-PRESSURE - DEMONSTRATION OF RECEPTOR STEREOSELECTIVITY USING (+)-TIFLUADOM AND (-)-TIFLUADOM
    (1987) URETA, H; LOPEZ, LF; PEREZ, A; HUIDOBROTORO, JP
    (+)-Tifluadom injected i.p. produced a biphasic response of urine output: within the first hour of its administration the drug produced antidiuresis followed by a diuretic phase. In contrast, the (-) isomer produced a modest reduction in urine output as compared to the output of the saline-treated rats. In addition, (+)-tifluadom markedly reduced the output of urinary Na+ and K+. The effects of (+)-tifluadom were blocked by 7.5 mg/kg naloxone but not by 10 mg/kg of the benzodiazepine antagonist Ro 15-1788. Parallel experiments demonstrated that the i.v. administration of (+)-tifluadom to non-anesthetized rats caused a dose-related pressor response that lasted for at least 15 min. This effect of (+)-tifluadom wa blocked and antagonized by naloxone. In contrast, (-)-tifluadom was either inactive on the cardiovascular system or produced short-lasting hypotension. In pentobarbital-anesthetized rats, 100 .mu.g/kg (+)-tifluadom caused a precipitous hypotension that was reversed by naloxone but not by Ro 15-1788.
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    POSTPARTUM CERVICAL-MUCUS - BIOLOGICAL AND RHEOLOGICAL PROPERTIES
    (1991) VIGIL, P; PEREZ, A; NEIRA, J; MORALES, P
    In this study we have evaluated the score, sperm migration and ultrastructural characteristics of cervical mucus present in amenorrhoeic women under exclusive breastfeeding at 30, 60, 90, 120, 150 and 180 days post-partum. Periovulatory mucus samples from seven normally cycling women were used as a control. The average scores of post-partum and periovulatory mucus were 4.6 +/- 0.4 and 14.1 +/- 0.5 respectively. Twenty-one (39%) of the 54 post-partum cervical mucus samples and all (100%) periovulatory mucus samples allowed sperm migration. Positive sperm migration into post-partum mucus was observed at all time intervals studied. The only parameter that correlated with sperm migration into post-partum mucus was ferning formation. Sperm migration was obtained in all post-partum mucus samples with a score > 8, but samples with scores between 2 and 7 also showed sperm penetration. Scanning electron microscopic studies showed the characteristic spongy appearance of periovulatory mucus. Post-partum mucus was formed by a dense mesh (rocky appearance), when samples were generally unable to sustain sperm migration, but samples where sperm migration occurred showed small areas of spongy mucus mixed with areas in which a dense mesh and high cellularity was observed.
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    THE IMPACT OF A HOSPITAL AND CLINIC-BASED BREAST-FEEDING PROMOTION PROGRAM IN A MIDDLE-CLASS URBAN-ENVIRONMENT
    (1993) VALDES, V; PEREZ, A; LABBOK, M; PUGIN, E; ZAMBRANO, I; CATALAN, S
    Hospital interventions in support of breastfeeding have been highly successful in areas where the indigenous population has a well established environment of breastfeeding. However, programmes designed to improve breastfeeding patterns in urban populations have met with mixed success. This paper presents a prospective intervention study with a control group in which a health system-based breastfeeding promotion programme was initiated to support optimal breastfeeding for both child health and child spacing. Following collection of control data, a four-step intervention programme (Breastfeeding Promotion Program) was instituted. This paper reports the process of the development of the intervention programme as well as the comparison of the control and study populations. Major findings include significant increases in duration of full breastfeeding from 31.6 per cent at 6 months in the control group to 66.8 per cent in the intervention group. The duration of lactational amenorrhea was similarly increased: 22 per cent of the control mothers and 56 per cent of the intervention group women were in amenorrhoea at 180 days. The cost-effectiveness of the hospital changes is illustrated.
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    TIMING OF CONCEPTION AND THE RISK OF SPONTANEOUS-ABORTION AMONG PREGNANCIES OCCURRING DURING THE USE OF NATURAL FAMILY-PLANNING
    (1995) GRAY, RH; SIMPSON, JL; KAMBIC, RT; QUEENAN, JT; MENA, P; PEREZ, A; BARBATO, M
    OBJECTIVE: Our purpose was to ascertain the effects of timing of conception on the risk of spontaneous abortion.
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    USE-EFFECTIVENESS OF THE OVULATION METHOD INITIATED DURING POSTPARTUM BREASTFEEDING
    (1988) PEREZ, A; LABBOK, M; BARKER, D; GRAY, R
    Between April 1981 to March 1984, 419 urban middle class postpartum women entered the Natural Family Planning (NFP) program of the Pontificia Universidad Catolica de Chile. This NFP program teaches the Ovulation Method (Billings). Only 1.9% of the women did not learn how to recognize the mucus pattern of fertility awareness. The sample of 378 women who were practicing the method to avoid a pregnancy completed 4,935 months of use of the OM. The cumulative life table unplanned pregnancy rate at the 12th postpartum month was 11.1 .+-. 1.9 and the Pearl Rate was 12.1 per 100 woman-years. The Pearl Rate calculation of method-related failure was only 2.1 pregnancies per 100 woman-years. The breastfeeding group showed a significantly lower rate of unplanned pregnancies than the nonbreastfeeding group and there was no significant increase in unplanned pregnancy at the time of menstruation among previously amenorrheic women as compared to later intervals. The protection against unplanned pregnancy shown in this study should be viewed as the combination of two factors: breastfeeding and the Ovulation Method (OM) of NFP.