PubMed Health⌕ Search

Biomedical subjects

C M Visness

Publications and source records attributed to C M Visness.

17 recordsLinked to original sources
PubMed1999

Estimates of the risk of cardiovascular death attributable to low-dose oral contraceptives in the United States.

OBJECTIVE: Our purpose was to estimate the annual risk of death in the United States from cardiovascular disease attributable to low-dose combination oral contraceptives. STUDY DESIGN: Estimates of the risk of death from cardiovascular disease attributable to low-dose oral contraceptives were modeled on data from studies published through 1997 and from age-specific mortality rates in the United States for 1993 and 1994. RESULTS: Attributable risk of death from cardiovascular disease resulting from oral contraceptive use is 0.06 and 3.0 per 100,000 nonsmokers 15 to 34 years of age and 35 to 44 years of age, respectively. In smokers this risk increases, respectively, to 1.73 and 19.4 per 100,000 users in these 2 age groups; however, 97% and 85% of this risk is due to the combined effects of smoking and using oral contraceptives. The attributable risk of death from cardiovascular disease in nonsmoking oral contraceptive users is lower than the risk of death from pregnancy in nonusers of oral contraceptives at all ages; however, among smoking oral contraceptive users more than 35 years of age, the excess risk of death from oral contraceptives is higher than the risk of death from pregnancy. CONCLUSION: There is virtually no excess attributable risk of death from cardiovascular disease related to oral contraceptive use in young women. However, smokers more than 35 years of age should use a nonestrogen contraceptive.

Adolescent↗
PubMed1998

Users' understanding of the lactational amenorrhea method and the occurrence of pregnancy.

It is unknown whether a user's understanding of the Lactational Amenorrhea Method (LAM) is related to its successful use. A study of 876 LAM users in Pakistan and the Philippines collected information about women's understanding of LAM. The present analysis aims to determine: (1) the proportion of LAM users who understand the method, (2) whether any known factors can distinguish those who understand LAM from those who do not, and (3) whether an understanding of LAM is related to subsequent pregnancy. Over 75% of LAM users could consistently recite the LAM guidelines correctly for a full year postpartum. However, 38% of users failed to display, at least once, an understanding of LAM during the first year postpartum mainly by failing to abstain, to use another method or to explain their nonuse of another method when their LAM protection expired. LAM understanding generally could not be predicted by sociodemographic factors. The occurrence of pregnancy during the first year postpartum was not related to LAM understanding, regardless of how LAM understanding was defined, nor could it be predicted by any other measured characteristic of the users.

Adult↗
PubMed1998

Views of Cameroonian sex workers on a woman-controlled method of contraception and disease protection.

Five hundred and twenty female Cameroonian sex workers participating in a clinical trial of the effectiveness of nonoxynol-9 (N-9) contraceptive film to prevent HIV infection were interviewed to determine their experience with this woman-controlled method. The sex workers liked the film, with over 80% stating they would continue to use it if it were shown to be effective against HIV and were to become widely available. However, they were much more likely to use condoms and films simultaneously with their clients (40%) than with their regular partners (16%). The advantages ascribed to the film were that its use was under the woman's control; it could be used without the partner's knowledge; it allowed direct contact between partners; and it provided back-up protection in case of condom breakage. Data from this small study suggest that development of an effective, woman-controlled method of pregnancy and disease protection would be welcomed by these women.

Acquired Immunodeficiency Syndrome↗
PubMed1997

The duration and character of postpartum bleeding among breast-feeding women.

OBJECTIVE: To examine the postpartum bleeding experience of a cohort of breast-feeding women and to compare it with the conventional definition of lochia. METHODS: Four hundred seventy-seven experienced breast-feeding women in Manila, the Philippines, were followed prospectively from delivery and recorded vaginal bleeding in a menstrual diary. The median duration of lochia was calculated using survival analysis. In addition, all bleeding separate from lochia within the first 8 weeks postpartum was noted. RESULTS: The median duration of lochia was 27 days and did not vary by age, parity, sex or weight of the infant, breast-feeding frequency, or level of supplementation. More than one-fourth of the women experienced a bleeding episode separated from the original lochial flow by at least 4 bleeding-free days and beginning no later than postpartum day 56. Ten breast-feeding women may have had their first menstrual bleed before day 56. CONCLUSIONS: Lochia lasted substantially longer than the conventional assumption of 2 weeks. It was common for postpartum bleeding to stop and start again or to be characterized by intermittent spotting or bleeding. Return of menses is rare among fully breast-feeding women in the first 8 weeks postpartum.

Adult↗
PubMed1997

Fertility of fully breast-feeding women in the early postpartum period.

OBJECTIVE: To examine bleeding between 6 and 8 weeks postpartum in fully breast-feeding women and its association with fertility as assessed by hormone analysis. METHODS: Seventy-two fully breast-feeding women were followed prospectively from 42 days postpartum. Vaginal bleeding was recorded daily. Women who experienced bleeding were compared with women who did not with respect to time of ovulation and time of first menses. RESULTS: Nearly half of the women experienced some vaginal bleeding or spotting between 6 and 8 weeks postpartum. These women eventually menstruated and ovulated earlier than the women who did not bleed, but the differences were not significant. The study had 34% and 45% power to detect a 20% difference in the proportion menstruating and ovulating, respectively, at 6 months postpartum, and 10% and 16% power to detect the same differences at 1 year. Seven women experienced ovarian follicular development before day 56, but neither bleeding nor follicular development was associated with ovulation in any woman in the first 8 weeks postpartum. CONCLUSIONS: It is unlikely that vaginal bleeding in fully breast-feeding women in the first 8 weeks postpartum represents a return to fertility.

Female↗
PubMed1997

The frequency of coitus during breastfeeding.

BACKGROUND: New mothers and clinicians would benefit from an understanding of typical sexual behavior during breastfeeding. Unfortunately, little information is available about both the typical length of time to resumption of coitus and the frequency of sexual relations during breastfeeding. This paper describes the commencement and frequency of coitus among breastfeeding women in a variety of settings. METHODS: The analysis draws on data from two separate research studies. The first was undertaken in three sites (Birmingham, United Kingdom; Montreal, Canada; Sydney, Australia), the purpose of which was to correlate natural observations of fertility with the underlying hormonal profile among breastfeeding women using the symptom-thermal method of natural family planning. The second was a clinical trial of the lactational amenorrhea method of family planning conducted in Manila, the Philippines. RESULTS: Coital frequency reported by these populations of breastfeeding women appears to be lower than that reported in other studies for married women in general. As other research demonstrated, we found coital frequency and postpartum resumption of coitus to be associated with age, but not with the number of children in the household. CONCLUSIONS: A better understanding of the level of sexual activity among breastfeeding women could inform and improve programs that offer postpartum support and counseling about family planning.

Adult↗
PubMed1997

A comparison of two U.S. surveys of infant feeding.

This study compares the 1988 National Maternal and Infant Health Survey (NMIHS) and the 1989 Ross Laboratories Mothers Survey with respect to sample characteristics and proportions of women who breastfed. Weighted proportions of women included in the two surveys were compared according to various characteristics to see how well they represented U.S. childbearing women. A z-statistic was produced to test for significant differences in the proportions who breastfed. In 1988-89, 52.2% of American women breastfed according to the Ross survey and 53.4% according to the NMIHS. Despite differences in sample size, sampling technique and the application of sample weights, the difference between the surveys was only 1 percentage point, and most levels of most variables examined were comparable. The Ross survey is a valuable source of data because it is ongoing, and it is generally corroborated by the NMIHS. The NMIHS is probably more representative of the U.S. population of childbearing women, and is a reliable source of data for setting U.S. objectives concerning infant feeding, and for the study of other issues vis-à-vis breastfeeding.

Breast Feeding↗
PubMed1997

Maternal employment and breast-feeding: findings from the 1988 National Maternal and Infant Health Survey.

OBJECTIVES: This analysis uses nationally representative data from the 1988 National Maternal and Infant Health Survey to explore the factors, including employment, associated with breast-feeding initiation and duration. METHODS: Multiple logistic regression was used to model the determinants of breast-feeding initiation among 9087 US women. Multiple linear regression was used to model the duration of breast-feeding among women who breast-fed. RESULTS: Fifty-three percent of mothers initiated breast-feeding in 1988, and the decision to breast-feed was not associated with maternal employment. However, among breast-feeders, returning to work within a year of delivery was associated with a shorter duration of breast-feeding when other factors were controlled. Among employed mothers, the duration of maternity leave was positively associated with the duration of breast-feeding. CONCLUSIONS: The low rates of breast-feeding initiation in the United States are not attributable to maternal participation in the labor force. However, returning to work is associated with earlier weaning among women who breast-feed.

Adult↗
PubMed1996

Effectiveness of lactational amenorrhoea in prevention of pregnancy in Manila, the Philippines: non-comparative prospective trail.

OBJECTIVE: To determine the contraceptive efficacy of the lactational amenorrhoea method. DESIGN: Non-comparative prospective trial. SETTING: Urban Manila, the Philippines. SUBJECTS: 485 lower income, educated women with extensive experience of breast feeding. INTERVENTION: Women were offered all available contraceptives for use after birth. Those who chose the lactational amenorrhoea method were taught the method, screened for the study, and followed for 12 months to determine the risk of pregnancy when the method was used. MAIN OUTCOME MEASURES: Life table pregnancy rates during correct and incorrect use of the method, censored monthly in the event of sexual abstinence or the use of another contraceptive method. RESULTS: The lactational amenorrhoea method was 99% effective when used correctly (that is, during lactational amenorrhoea and full or nearly full breast feeding for up to six months). At 12 months the effectiveness during amenorrhoea dropped to 97%. CONCLUSIONS: The lactational amenorrhoea method provided as much protection from pregnancy as non-breast feeding women experience with non-medicated intrauterine devices and barrier methods. The contraceptive effect of lactation cannot be attributed to lactational or postpartum abstinence.

Adult↗
PubMed1995

Progestin-only pill use and pill switching during breastfeeding.

The opinions of 20 international experts in reproductive endocrinology and family planning service delivery were solicited concerning contraceptive pill use during breastfeeding and, in particular, to determine whether the experts felt that breastfeeding women who use progestin-only pills (POPs) should be advised to switch to combined estrogen-progestin pills (COCs) during lactation. The experts agreed that POPs can be used safely and effectively throughout the period of lactation and there is no need to switch to another contraceptive method or another type of pill. If, however, a woman wishes to switch to COCs while she is still breastfeeding, it is acceptable for her to do so after six months postpartum.

Contraceptives, Oral, Hormonal↗
PubMed1995

Effectiveness of the lactational amenorrhea method in Pakistan.

OBJECTIVE: To determine the efficacy of the lactational amenorrhea method of family planning (amenorrhea during full or nearly full breastfeeding for 6 months postpartum). DESIGN: Prospective noncomparative study. SETTING: Normal breastfeeding women in Karachi and Multan, Pakistan, most delivered at home by a midwife. PATIENTS: Three hundred ninety-nine newly delivered mothers who successfully had breastfed a previous child and chose the lactational amenorrhea method to prevent a subsequent pregnancy, 391 of whom were followed for a full year. INTERVENTIONS: Mothers were taught, before or shortly after delivery, to use the method and were interviewed in their homes each month by a Lady Health Visitor. MAIN OUTCOME MEASURE: Life-table pregnancy rates. Periods of postpartum or lactational abstinence were excluded in the calculation of the pregnancy rates. RESULTS: During full or nearly full breastfeeding, while the women were amenorrheic and not otherwise contracepting, the rate of pregnancy was 0.6%. The pregnancy rate during lactational amenorrhea alone was 1.1% at 1 year postpartum. CONCLUSION: The lactational amenorrhea method was found to be highly effective for 6 months. A high degree of contraceptive protection endures for a full year during lactational amenorrhea, but not after the return of menses during breastfeeding.

Adolescent↗
PubMed1992

Contraceptive efficacy of lactational amenorrhoea.

Pregnancy is rare among breastfeeding women with lactational amenorrhoea. The lactational amenorrhoea method (LAM) is the informed use of breastfeeding as a contraceptive method by a woman who is still amenorrhoeic, and who is not feeding her baby with supplements, for up to 6 months after delivery. Under these three conditions, LAM users are thought to have 98% protection from pregnancy. It can be difficult, however, to determine when supplementation of the baby's diet begins. We have analysed data from nine studies of the recovery of fertility in breastfeeding women to assess the effectiveness of lactational amenorrhoea alone, irrespective of whether supplements have been introduced, as a fertility regulation method post partum. Cumulative probabilities of ovulation during lactational amenorrhoea were 30.9 and 67.3 per 100 women at 6 and 12 months, respectively, compared with 27.2 at 6 months when all three criteria of the LAM were met. Cumulative pregnancy rates during lactational amenorrhoea were 2.9 and 5.9 per 100 women at 6 and 12 months, compared with 0.7 at 6 months for the LAM. The probability of pregnancy during lactational amenorrhoea calculated from these studies is similar to that of other modern contraceptive methods, and it seems reasonable for a woman to rely on lactational amenorrhoea without regard to whether she is fully or partly breastfeeding. So that amenorrhoea and fertility suppression can be maintained, counselling about good breastfeeding and weaning practices remains important.

Actuarial Analysis↗
PubMedDate not supplied

Breastfeeding and the symptothermal method.

This prospective study was conducted among experienced users of periodic abstinence methods in Sydney, Montreal, and Birmingham (England) in order to describe the relationship between a laboratory measurement of ovulation and the natural symptoms of fertility during breastfeeding. Daily urinary estrogen and pregnanediol glucuronide assays were used to estimate the date of ovulation and to determine potentially fertile days. A standard set of Symptothermal Method (STM) rules was applied to daily STM records to assess the correspondence of the natural symptoms of fertility to the underlying hormonal profile. The STM symptoms and rules accurately identified 77-94 percent of the women's potentially fertile days, but abstinence was also recommended on about half of the days when the women were not fertile. An integrated set of common rules for STM use during breastfeeding is highly sensitive but not specific in its ability to screen for ovulation.

Adult↗