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Biomedical subjects

R T Kambic

Publications and source records attributed to R T Kambic.

7 recordsLinked to original sources
PubMed1991

Fetal outcome among pregnancies in natural family planning acceptors: an international cohort study.

This international, multicenter, prospective cohort study examines the outcome of pregnancies associated with aging gametes. Comparing pregnancies conceived at or near the peak mucus phase with those occurring before or after the peak provides a means of evaluating the effect of aging gametes. The outcome criteria are (1) rates of spontaneous abortion, (2) low birth weight, and (3) congenital malformations. Preliminary analysis shows a trend toward increased spontaneous abortion with aging gametes in certain subsets (women with prior pregnancy losses) but no effect on birth weight. Too few method failures have yet been studied to make a definitive statement on congenital malformations.

Family Planning Services↗
PubMed1991

Natural family planning use-effectiveness and continuation.

Numerous studies have been conducted to assess the use-effectiveness of natural family planning. However, because of imprecise definitions of terms, these studies show noncomparable results. Special effort is required to study natural family planning use-effectiveness by the same criteria as other family planning methods.

Family Planning Services↗
PubMed1991

Factors related to autonomy and discontinuation of use of natural family planning for women in Liberia and Zambia.

From 1983 to 1988, natural family planning programs were conducted in Liberia and Zambia. In Liberia 1055 and in Zambia 2709 women used natural family planning to avoid pregnancy. These users could become pregnant, discontinue use of the method, or become autonomous users. Women who changed intention did not stop use of natural family planning and were not treated as discontinuations. In a multivariate analysis, client's age, breastfeeding status, employment, urban/rural residence, time of registration in the program, and visit intensity were significantly associated with the outcomes. The most consistent association was that women who entered the programs in the later time periods were more likely to become autonomous users and less likely to discontinue use of the method or to experience an accidental pregnancy.

Adolescent↗
PubMed1988

Pregnancy outcome associated with natural family planning (NFP): scientific basis and experimental design for an international cohort study.

Although natural family planning (NFP) is a form of contraception without ostensible maternal risks (other than pregnancy), potential fetal risks could exist if aging gametes are involved in inadvertent fertilization. In the following report, we first review animal studies firmly establishing that aging sperm and aging oocytes (delayed fertilization) cause chromosomal abnormalities in mammals and other species. We next review human studies associating decreased coital frequency with trisomy and studies of NFP populations that generally show no increased frequency of anomalous offspring or spontaneous abortions. Our rationale for initiating an international cohort study is presented, along with the experimental design selected. Preliminary findings indicate that the experimental design chosen will indeed provide information allowing NFP safety to be assessed definitively.

Aging↗
PubMed1988

Evaluating client autonomy in natural family planning.

A critical element for evaluation of natural family planning (NFP) methods is client autonomy. Autonomy in NFP refers to clients who can identify their fertile days and apply this method without teacher assistance. The results of this study show that clients who are autonomous have a 12-month continuation rate of 96.7% and a pregnancy rate of 1.7% after beginning charting. The non-autonomous clients had a 12-month continuation rate of 34.3% and a pregnancy rate of 24.8% after beginning charting, significantly different from the autonomous clients. Using a bivariate analysis, we found that women 30 years and older who had two children or more, and women in the same age group (30 years and older) who wanted to limit rather than space pregnancy were significantly more likely to become autonomous. These findings have implications for NFP programs and future evaluation efforts.

Adult↗
PubMed1988

Epidemiological studies of natural family planning.

The prevalence of the use of natural family planning (NFP) can be estimated from sample surveys of married women in the reproductive ages (MWRA). Surveys in developed and developing countries during the past decade indicate that the prevalence of NFP use varies from 0 to 11%. In addition, if one considers NFP use in relation to other contraceptive methods, the percentage of all current contraceptors who use NFP varies from 1 to 35%. This suggests that NFP is an important method in certain countries. Pregnancy rates for NFP vary widely, but most reliable studies report 1-year life-table pregnancy rates between 10 and 25/100 woman-years. The Billings ovulation method consistently has higher pregnancy rates than the sympto-thermal method and NFP users generally have among the highest pregnancy rates compared to other methods. The major safety issue concerning NFP is the risk of adverse pregnancy outcomes associated with aged gametes. There are suggestions from a number of investigations that conceptions distant from ovulation have a higher risk of spontaneous abortion and a higher proportion of male births. The findings with respect to birth defects or multiple pregnancies are less consistent, although some studies have reported an increased risk of chromosomal anomalies.

Abortion, Spontaneous↗