Issues in Interdisciplinarity 2020-21/Evidence in Hormonal Contraception

Introduction
Hormonal contraception exists in several forms, including oral pills, vaginal rings or skin patches, all sharing the same mechanism: they influence female hormone levels to prevent ovulation, with a wide application in birth control and treating menstrual symptoms.

Due to such broad usage, research considers evidence from multiple disciplines, including biology and psychology, when regarding the development of new or currently available contraception. This range of studies produces a variety of evidence which in itself presents interdisciplinary tensions. Therefore, an insight into such tensions between biology and psychology will better the understanding of hormonal contraception by policy makers and the general public, improving their everyday use and effectiveness.

Evidence in biology
Most of the biological evidence relating to hormonal contraceptives is produced through randomised control trials (RCTs), or large, non-comparative multi-centre registration studies. A problem in the field is that both these designs, although less so in RCTs, run the risk of producing biased evidence as the companies that manufacture the study contraceptive fund and undertake these studies themselves. Furthermore, the sampling frames consist of mostly Europeans or Americans, with research lasting only 365 days evaluating up to 8 menstrual cycles. Hence, long-term health effects of hormonal contraceptives are undocumented.

Within the discipline, evidence for hormonal contraception is varied. This is due to the fact that synthetic hormones affect bodily hormone production, leading to several physiological changes. This forces biological research to use several specialised methodologies to measure each effect.

One problematic assumption in the biological study of hormonal contraceptives is the application of self-reports to generate quantitative measurements. This links to the issue of inconsistently defined terminology such as “continuation,” “compliance”, “adherence,” “misuse”, “nonuse,” and “correct use”. The reliance of self-report studies on these unstandardised definitions produces conflicting evidence and limits the observation of negative outcomes.

Most importantly, biologists fail to capture the full complexity of contraceptives due to the general lack of research towards non-physiological effects of hormonal treatments, or menstruation-associated symptoms, participant satisfaction, and long-term health effects due to continuous contraceptive use. There is a preference within biology to consider only physical conditions in evidence. Many epidemiological case studies suggest increased risks of venous thromboembolism, ischemic stroke, and myocardial infarction, all of which are easily tested and objectively quantifiable conditions.

Evidence in psychology
“Literature testing psychological implications of commencing oral contraceptives has lagged behind research investigating physical risks.” - Kobey and Bunnk, 2012.

Despite this, the field pushes for a greater understanding of long-term consequences in hormonal contraception use. There is a heavier use of meta-analyses as the field takes advantage of previous psychological research. Alongside these meta-analyses the psychological evidence also focuses on the use of in-person interviews and population based studies; these aid in giving a longer-term perspective with a more qualitative approach.

The research conducted to review effects of hormonal contraception, formed over a larger time scale than biological research, not only analyses the impact at both a neurological or hormonal level, but also a behavioural level. This helps to diagnose sources of certain mental illnesses and the hormones used in contraception which serve to aggravate them.

Research methods also include subjective discussions on second wave feminism and the impact of contraception on the workforce due to a relation to women’s health and psychology. There exists further qualitative observation of the impact of hormones on primates, and qualitative studies relating to behavioural patterns in women. These studies carried out on primates and then women show an impact not only upon the physical health of the individual, though it is noted that these specifications fall more in line with biological research, but also upon levels of aggression and depression. However, primates may be considered sufficiently distant to humans that they yield uncertain evidence regarding possible human consequences.

Tensions
Differences in evidence type present one avenue in which tensions arise. Many biological studies are clinical, randomised-control trials, such as Osuga, Hayashi and Kanda’s 2020 study. Effects of hormonal contraception on a large sampling frame are numerically ‘scored’, with results statistically analysed; this produces primary evidence which is largely quantitative and removes any subjective aspect of personal experience. In psychology however, there is a focus on using reports and interviews to generate evidence; the emphasis is on personal experiences with contraception and impacts on mental health and sexual activity. Evidence such as this is gathered from more subjective, situational studies as opposed to the objective and statistical biological experiments.

Another tension arises within the differing uses of self-report based evidence. In biology, this evidence is treated as quantitative and generally not deeply evaluated; in many experiments abnormal personal experiences are excluded from calculations. This same self-reported data in psychological research is treated as qualitative evidence and is analysed to draw new conclusions, suggesting reasons for the abnormalities. The issue of unclear terminology regarding participant conditions in biological research further demonstrates this lack of focus on individual participant action. Alternatively, in psychology, this terminology is standardised as individual experiences are usually the focus of the research.

Furthermore, biological studies considering the safety of contraception may focus more on physical side-effects, such as abnormal bleeding. The mental side-effects considered in psychological studies may take longer to manifest themselves. As such, the evidence gathered in biology considers seemingly more physical or ‘tangible’ side-effects. This could mean that biological evidence is deemed more valid than its psychological counterpart; here another tension becomes apparent as there is a notion of necessity in biological research but not psychological.

Conclusion
In the development of hormonal contraceptives, there is greater focus on biological research when first considering drug viability, with psychological studies carried out following this. While hormonal contraception has been in use for over 50 years, suggesting high levels of biological research, the psychological effect of contraception on stress responses and emotional memory remains unexplored; it is only in recent years that this is being considered. This can be attributed to the fact that production of evidence in psychology is somewhat limited to studying patented products already in use, while biology is not. In order to overcome such limitations, an interdisciplinary study of contraception will be beneficial.

Regarding the study of long-term effects, longer research periods mean that psychological studies ‘lag’ significantly behind biological ones. Policy makers therefore may consider biological evidence a priority, and psychological evidence an afterthought. In light of this, when considering the viability of a contraceptive drug, there are ethical concerns testing for psychological effects in a substance not yet clinically trialled. However, the amount of time required for the long-term psychological study of contraceptives may mean that drug companies prefer to develop drugs after only clinical tests; this is concerning considering mental health is equally as important as physical. With this rising consideration regarding mental health, policy makers may take an interest in an interdisciplinary approach to hormonal contraception development.

Lastly, after considering current tensions, there is also some progress toward an interdisciplinary approach. Currently there is little use of the psychological perspective within biology, however in psychological meta-analyses there are references to biological evidence. This shows a promising interdisciplinary future within the study of hormonal contraception.