The State of the Science of Natural Family Planning Fifty Years after Humane Vitae: A Report from NFP Scientists’ Meeting Held at the US Conference of Catholic Bishops, April 4, 2018

A one-day meeting of physicians, professional nurses, and scientists actively involved in Natural Family Planning (NFP) research was held to review the state of the science of NFP and consider future priorities. The meeting had four objectives: (i) determine the gaps in research evidence for secure methods of NFP among women of all reproductive categories, (ii) determine the gaps in the research and development of new technology for providing NFP services, (iii) determine the gaps in the research that determine the benefits and challenges with use of NFP among married couples, and (iv) provide prioritized ideas for future research needs from the analysis of evidence gaps from objectives above. This article summarizes the discussion and conclusions drawn from topics reviewed. While much has been accomplished in the fifty years since Humane vitae, there are still many gaps to address. Five areas for future research in NFP were identified as high priority: (1) well-designed method effectiveness studies among various reproductive categories including important subpopulations (postpartum, perimenopause, posthormonal contraceptive), normally cycling women (especially US women), and comparative studies between NFP methods; (2) validation studies to establish the benefit of charting fertility signs (both currently known and potential new indicators) as a screening tool for women’s health issues; (3) ongoing independent evaluation of fertility monitoring apps to provide users perspective on the relative merits of each and to identify those most worthy of further effectiveness testing; (4) studies evaluating the impact of new technologies on NFP adoption, use, and persistence; and (5) creation of a shared database across various NFP methods to collaborate on shared research interests, longitudinal studies, and so on. This summarizes a meeting to review the scientific and medical progress related to natural family planning made in the 50 years since Humane Vitae and to define priorities for future work. Areas reviewed included the evidence for avoiding pregnancy in normally cycling, postpartum, and perimenopausal women, the impact of new technology, including fertility charting apps, on NFP, and the impact on relationships and personal well-being from use of NFP. Five priority focus areas for future research were also identified

Statistical Physics of Evolutionary Trajectories on Fitness Landscapes

Random walks on multidimensional nonlinear landscapes are of interest in many areas of science and engineering. In particular, properties of adaptive trajectories on fitness landscapes determine population fates and thus play a central role in evolutionary theory. The topography of fitness landscapes and its effect on evolutionary dynamics have been extensively studied in the literature. We will survey the current research knowledge in this field, focusing on a recently developed systematic approach to characterizing path lengths, mean first-passage times, and other statistics of the path ensemble. This approach, based on general techniques from statistical physics, is applicable to landscapes of arbitrary complexity and structure. It is especially well-suited to quantifying the diversity of stochastic trajectories and repeatability of evolutionary events. We demonstrate this methodology using a biophysical model of protein evolution that describes how proteins maintain stability while evolving new functions

Biophysical Fitness Landscapes for Transcription Factor Binding Sites

Evolutionary trajectories and phenotypic states available to cell populations are ultimately dictated by intermolecular interactions between DNA, RNA, proteins, and other molecular species. Here we study how evolution of gene regulation in a single-cell eukaryote S. cerevisiae is affected by the interactions between transcription factors (TFs) and their cognate genomic sites. Our study is informed by high-throughput in vitro measurements of TF-DNA binding interactions and by a comprehensive collection of genomic binding sites. Using an evolutionary model for monomorphic populations evolving on a fitness landscape, we infer fitness as a function of TF-DNA binding energy for a collection of 12 yeast TFs, and show that the shape of the predicted fitness functions is in broad agreement with a simple thermodynamic model of two-state TF-DNA binding. However, the effective temperature of the model is not always equal to the physical temperature, indicating selection pressures in addition to biophysical constraints caused by TF-DNA interactions. We find little statistical support for the fitness landscape in which each position in the binding site evolves independently, showing that epistasis is common in evolution of gene regulation. Finally, by correlating TF-DNA binding energies with biological properties of the sites or the genes they regulate, we are able to rule out several scenarios of site-specific selection, under which binding sites of the same TF would experience a spectrum of selection pressures depending on their position in the genome. These findings argue for the existence of universal fitness landscapes which shape evolution of all sites for a given TF, and whose properties are determined in part by the physics of protein-DNA interactions

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Natural Family Planning and Marital Chastity: The Effects of Periodic Abstinence on Marital Relationships

Marital chastity is the practice of periodic abstinence with use of natural family planning (NFP). The purpose of this study was to determine the influence of the most common methods of contraception (female sterilization, oral contraceptive pills, and condoms) and NFP on divorce/separation and cohabitation rates among reproductive age women. The study involved an extensive review of the literature on the effects of practice of NFP on marital dynamics and a statistical analysis of 2,550 ever-married women in the (2015–2017) National Survey of Family Growth data set. Importance of religion and frequency of church attendance were included in the analysis. With ever-use of NFP, 14 percent were divorced or separated, and 27 percent to 39 percent were divorced or separated with ever-use of oral contraceptive pills. Stepwise logistic regression indicated that ever-use of contraception was associated with increased odds of divorce or separation (odds ratio [OR] = 2.05; confidence interval [CI]: 1.96–2.49) and cohabitation (2.95, CI: 2.20–3.95). Ever-use of NFP yielded 58 percent lower odds for divorce or separation. Frequent church attendance was associated with lower odds of divorce or separation and cohabitation. Although there are lower odds of divorce among NFP users, the reason might be due to their religiosity