The effect of lavender on mood disorders associated with the use of combined oral contraceptives (COCs): a triple-blinded randomized controlled trial

BACKGROUND

The use of contraceptive methods is influenced by their effectiveness, availability, and minimal side effects. OCPs are one of the most effective and widely used methods of pregnancy prevention worldwide. This method not only prevents pregnancy but also helps prevent and treat other diseases. One of the main reasons for discontinuing this method is the emotional disturbances associated with its use. Lavender is an evergreen, fragrant plant that has gained significant attention for its anti-anxiety effects. This study was conducted to investigate the effect of lavender essential oil capsules on mood disorders during the use of COCs.

METHODS

This triple-blinded clinical trial was conducted on 60 married women (aged 15-49 years old) who were consumers of COCs, referring to 26 health centers in Tabriz, Iran. The participants were randomly assigned to either the intervention (consuming one gelatin capsule containing 80 mg LEO daily) or control (consuming one placebo capsule daily) group. The intervention continued for 56 days. Scores for positive and negative were determined using the Positive and Negative Affect Schedule (PANAS) questionnaire; and for stress, depression, and anxiety were measured using the DASS-21 questionnaire on day's 28th and 56th post-intervention. Data analysis was conducted using the t-test and ANOVA with repeated measures, and a p-value of < 0.05 was considered significant for all analyses.

RESULTS

A statistically significant difference was observed in mood disorders, stress, and depression between women receiving LEO or placebo. The consumption of LEO increased the positive mood on day 28 [MD (95% CI): 4.5 (2.1 to 7.0), p = 0.001] and day 56 [5.9 (3.4 to 8.3), p < 0.001] while decreased the negative mood on day 28 [MD (95% CI): -3.5 (-5.3 to -1.3), p < 0.001] and day 56 [-4.3 (-6.3 to -2.2), p < 0.001], stress on day 28 [MD (95% CI): -4.9 (-7.1 to -2.8), p = 0.001] and day 56 [-5.3 (-7.6 to -3.1), p < 0. 001], and depression on day 28 [MD (95% CI): -3.0 (-4.9 to 1.1), p = 0.003] and day 56 [-3.1 (-5.0 to 1.2), p = 0.002]. There was no statistically significant difference between the two groups in terms of anxiety.

CONCLUSIONS

The consumption of LEO with COCs improved mood disorders and reduced stress and depression. The use of hormonal contraceptives and mood changes should be considered by providers. Therefore, regarding the possibility of mood changes, it is expected that appropriate counseling and education will be provided to women who consume COC., providing appropriate solutions, including the simultaneous use of LEO.

Hormonal status effects on the electrophysiological correlates of performance monitoring in women

Fluctuations in ovarian hormones are thought to play a role in the increased prevalence of mood and anxiety disorders in women. Error-related negativity (ERN) and error positivity (Pe) are two putative electrophysiological biomarkers for these internalizing disorders. We investigated whether female hormonal status, specifically menstrual cycle phase and oral contraceptive (OC) use, impact ERN and Pe. Additionally, we examined whether the relationship between the ERN and negative affect (NA) was moderated by hormonal status and tested whether the ERN mediated the relation between ovarian hormones and NA. Participants were healthy, pre-menopausal women who were naturally cycling (NC) or using OCs. Using a counterbalanced within-subject design, all participants performed a speeded-choice reaction-time task twice while undergoing electroencephalography measurements. NC women (N = 42) performed this task during the early follicular and midluteal phase (when estrogen and progesterone are both low and both high, respectively), while OC users (N = 42) performed the task during active OC use and during their pill-free week. Estradiol and progesterone levels were assessed in saliva. Comparing the two cycle phases within NC women revealed no differences in the (Δ)ERN, (Δ)Pe or NA. We did observe a negative relation between phase-related changes in the ΔERN and changes in NA. Mediation analysis additionally showed that phase-related changes in estradiol were indirectly and negatively related to NA through a reduction of ΔERN amplitudes. When comparing active OC users with NC women, we observed increased ΔPe- but not (Δ)ERN amplitudes in the former group. No evidence was found for moderating effects of menstrual cycle phase or OC use on the relation between the ERN and NA. These findings suggest that hormonal status may impact the neural correlates of performance monitoring and error sensitivity, and that this could be a potential mechanism through which ovarian hormones influence mood.

Effects of the Combined Contraceptive Vaginal Ring on Female Sexual Function: A Systematic Review and Meta-analysis

There are controversial debates regarding the effects of contraceptive vaginal ring devices on females' sexual function. Therefore, the meta-analysis of before-after was conducted on the intervention studies published in the past years to clarify these contradictions. The existing literature on the subject was reviewed by searching through such databases as PubMed, Scopus, ISI Web of Sciences, Embase, Cochrane Library and Google Scholar up to July 2021. Before-after intervention studies that had examined the effect of vaginal rings on females' sexual function were collected as well. In total, five studies with 369 participants were included in quantitative syntheses. Pooled results from the random-effect model showed that NuvaRing had a positive effect on females' sexual function three months after insertion (WMD: 2.48; 95% CI: 0.30, 4.67; P = 0.026); however, this effect was not significant after 6 months (WMD: 4.38; 95% CI: -4.95, 13.72; P = 0.357). Meta-regression analysis suggested that the effect of this device is associated with users' age and body mass index 3 months after insertion. No publication bias was found by Egger's test or funnel plots. Overall, the results of this meta-analysis support the view that vaginal ring use is associated with a positive effect on the sexual function of women 3 months after insertion, while the effect of this device on the sexual function of women was insignificant after 6 months. However, given the dearth of available data, it is not possible to reach a definite conclusion on the effect of vaginal rings on females' sexual function.

Analysis of Adverse Events and Medical Errors in Long-Term Hormone Treatments for Endometriosis: A Study Based on the US Food and Drug Administration Event Reporting System

Purpose

To investigate adverse events and medical errors, as well as their possible risk factors, of combined oral contraceptives and progestins used in patients with endometriosis.

Patients and Methods

Reports between January 1, 2014 and September 30, 2021 about patients with endometriosis in US Food and Drug Administration Adverse Event Reporting System were analyzed. Disproportional analysis was performed with the Gamma-Poisson Shrinker model to detect overreported drug-event pairs. Logistic regression analysis was utilized to explore potential risk factors.

Results

There were 823 reports on long-term hormone treatments and 6247 reports on other drugs after removing duplicates, most of which were reported by consumers and were from the United States. Procedural complications and product issues were common among long-term hormone treatment users, while some other new adverse events emerged in subgroup analysis of different dosage forms of progestin. Polytherapy was negatively associated with off label use (adjusted OR = 0.47, 95% CI 0.22–0.94) and product use in unapproved indication (adjusted OR = 0.36, 95% CI 0.15–0.76) for combined oral contraceptive users. Combined oral contraceptive users aged greater than or equal to 30 were less likely to have product use issue (adjusted OR = 0.33, 95% CI 0.12–0.82) but were at higher risk of pulmonary embolism (adjusted OR = 4.04, 95% CI 1.35–17.43).

Conclusion

Long-term hormone treatment products in this study are generally safe for endometriosis, while newly detected signals need to be validated by further exploration. Patients’ tolerance and fertility desire should be considered when preparing treatment plans.

Hormonal contraceptives as disruptors of competitive behavior: Theoretical framing and review

Emerging evidence suggests that hormonal contraceptives (HCs) impact psychological outcomes through alterations in neurophysiology. In this review, we first introduce a theoretical framework for HCs as disruptors of steroid hormone modulation of socially competitive attitudes and behaviors. Then, we comprehensively examine prior research comparing HC users and non-users in outcomes related to competition for reproductive, social, and financial resources. Synthesis of 46 studies (n = 16,290) led to several key conclusions: HC users do not show the same menstrual cycle-related fluctuations in self-perceived attractiveness and some intrasexual competition seen in naturally-cycling women and, further, may show relatively reduced status- or achievement-oriented competitive motivation. However, there a lack of consistent or compelling evidence that HC users and non-users differ in competitive behavior or attitudes for mates or financial resources. These conclusions are tentative given the notable methodological limitations of the studies reviewed. Implications and recommendations for future research are discussed.

Sexual Functioning, Satisfaction, and Well-Being Among Contraceptive Users: A Three-Month Assessment From the HER Salt Lake Contraceptive Initiative

Few large, longitudinal studies document multiple contraceptive methods' effects on sexual functioning, satisfaction, and well-being. We leveraged data from the HER Salt Lake Contraceptive Initiative, a prospective cohort study with patient surveys at baseline, one month, and three months. Surveys assessed bleeding changes, contraceptive-related side effects, sexual functioning and satisfaction, and perceptions of methods' impact on sexual well-being. Individuals in the final sample (N = 2,157) initiated either combined oral contraceptives, levonorgestrel intrauterine devices (IUDs), copper IUDs, implants, injectables, or vaginal rings. Across methods, participants exhibited minimal changes in sexual function (Female Sexual Function Index-6 scores) or satisfaction (New Scale of Sexual Satisfaction scores) over three months. However, many perceived contraception-related changes to sexual well-being. Half (51%) reported their new method had made their sex life better; 15% reported it had made their sex life worse. Sexual improvements were associated with decreased vaginal bleeding, fewer side effects, and IUD use. Negative sexual impacts were associated with physical side effects (e.g., bloating and breast tenderness), increased bleeding, and vaginal ring use. In conclusion, contraceptive users did not experience major changes in sexual functioning or satisfaction over three months, but they did report subjective sexual changes, mostly positive, due to their method.

Blood testosterone levels in sickness and in health: Male chimpanzee testosterone levels decrease in face of an immune challenge

As an integral part of the immune response, testosterone secretion is inhibited when an individual is confronted with an immune challenge. Testosterone-mediated physiological, morphological, and behavioral traits are compromised at times of impaired health. Nevertheless, males of some species seem to maintain high levels of testosterone when confronted with an immune challenge, upholding competitive strength but compromising their immune response. It has been argued that this phenomenon will occur only in species living in social systems with high degrees of male-male competition over mating opportunities. Male chimpanzees contest over access to fertile females and dominants sire the majority of offspring. This male mating pattern makes chimpanzees a candidate species where we could expect males to maintain high testosterone levels, compromising their immune response, to ensure immediate reproductive success. We measured blood testosterone levels in male and female chimpanzees, who expressed clinical symptoms (symptomatic) or showed no evidence of clinical disease on assessment (asymptomatic). For females, we expected to find lower testosterone levels in symptomatic individuals than in asymptomatic subjects. In males, we would predict lower testosterone levels in symptomatic individuals than in asymptomatic males, if the immune response leads to a decrease in testosterone secretion. Alternatively, males could have equal levels of testosterone when symptomatic and asymptomatic, upholding competitive strength. Our results show that male chimpanzees exhibit lower levels of testosterone when confronted with an immune challenge than when being asymptomatic. This suggests that male testosterone secretion is suppressed as part of the immune response, which potentially increases survival and lifetime reproductive success. It will, however, negatively impact momentary competitive ability. Also, males may employ different mating strategies, some of which are less testosterone-driven (e.g., affiliative strategies). Consequently, in some individuals, the costs of maintaining high testosterone levels may not outweigh the potential gain in reproductive success.

Hormonal Contraception and Violent Death: The Physiological and Psychological Links

In the past decade, two large prospective cohort studies of British and American women have been conducted which found a statistically significant increase in the risk of violent death in ever-users of hormonal contraceptives. Research on the effects of hormonal contraceptives upon the behaviors of intimate partners and on the physiology of women using hormonal contraceptives has provided insight into the possible basis for the resulting increase in violent death. This review examines the changes that are potential contributors to the reported increase.

Is There an Association Between Contraception and Sexual Dysfunction in Women? A Systematic Review and Meta-analysis Based on Female Sexual Function Index

BACKGROUND

A growing body of research investigates the sexual functioning status in women with contraceptives use; however, the evidence is still inconclusive.

AIM

To examine whether contraceptives use is associated with a higher risk of female sexual dysfunction (FSD).

METHODS

The electronic databases MEDLINE, Embase, Cochrane Library databases, and PsychINFO were systematically screened for eligible studies before December 2019. We only included those studies assessing women's sexual functioning by the Female Sexual Function Index (FSFI). This study was registered on the PROSPERO (ID: CRD42020167723, http://www.crd.york.ac.uk/PROSPERO).

OUTCOMES

The strength of the association between contraceptives use and risk of FSD was presented by calculating the standard mean dierences (SMDs) and the relative risk (RR) with a 95% confidence interval (CI). The pooled results were calculated using a random-effects model.

RESULTS

A total of 12 studies (7 cross-sectional studies, 3 cohorts, and 1 case-control study) involving 9,427 participants were included. The mean age in the contraceptive users ranged from 22.5 ± 2.4 years to 38.2 ± 4.6 years, while the mean age in the nonusers was 22.5 ± 2.4 years to 36.0 ± 1.0 years. Pooled results showed that no significant difference in the total FSFI scores was observed between contraceptives use and noncontraception (SMD = -1.03, 95% CI: -2.08 to 0.01, P = .053; heterogeneity: I² = 98.2%, P < .001). In line with this finding, the pooled RR also yielded no association between contraception use and the risk of FSD (RR = 1.29, 95% CI: 0.72-2.28, P = .392; heterogeneity: I² = 76.0%, P = .0015). However, the subscale sexual desire showed a significant reduction in women who received contraceptives than those did not use contraception (SMD = -1.17, 95% CI: -2.09 to -0.24, P = .014; heterogeneity: I² = 97.7%, P < .001), while no significant differences were found in sexual arousal, lubrication, orgasm, satisfaction, and pain domain.

CLINICAL IMPLICATIONS

Though evidence from this meta-analysis did not support an association between contraceptives use and the risk of FSD, the sexual desire could be significantly impaired by contraceptives use.

STRENGTHS & LIMITATIONS

This is the first meta-analysis quantifying the relationship between contraceptives use and the risks of FSD. However, substantial heterogeneities were presented across the included studies.

CONCLUSION

No direct association between contraceptives use and the risk of FSD was found. Nevertheless, declining sexual desire was significantly associated with contraceptives use. Additional double-blind, randomized, placebo-controlled trials are still warranted. Huang M, Li G, Liu J, et al. Is There an Association Between Contraception and Sexual Dysfunction in Women? A Systematic Review and Meta-analysis Based on Female Sexual Function Index. J Sex Med 2020;17:1942-1955.

A brief guide to the menstrual cycle and oral contraceptive use for researchers in behavioral endocrinology

There is increasing evidence that reproductive hormones exert regulatory effects in the central nervous system that can influence behavioral, cognitive, perceptual, affective, and motivational processes. These effects occur in adults and post-pubertal individuals, and can be demonstrated in humans as well as laboratory animals. Large changes in 17β-estradiol and progesterone occur over the ovarian cycle (i.e., the menstrual cycle) and afford a way for researchers to explore the central nervous system (CNS) effects of these hormones under natural physiological conditions. Increasingly, oral contraceptives are also being studied, both as another route to understanding the CNS effects of reproductive hormones and also as pharmacological agents in their own right. This mini-review will summarize the basic physiology of the menstrual cycle and essential facts about oral contraceptives to help novice researchers to use both paradigms effectively.

Hormonal contraceptive use predicts decreased perseverance and therefore performance on some simple and challenging cognitive tasks

A growing body of research suggests that hormonal contraceptive (HC) use may be associated with lower self-control, as well as structural and functional differences in women's brains that could contribute to differences in perseverance on tasks requiring cognitive control. Here, we sought to extend this research by examining the relationship between HC use and college-aged women's perseverance (i.e., time spent) and performance on tasks requiring cognitive control. Across two studies, we find that, compared to naturally-cycling women, women using HCs display less perseverance on both simple (i.e., a spot-the-difference game) and challenging (i.e., Graduate Record Examination quantitative problems) tasks. Moreover, these differences in perseverance were found to predict performance decrements across tasks, with women taking HCs performing worse because they spent less time on the tasks. By demonstrating how HC use may influence perseverance and thereby performance, these results contribute to a growing body of research examining the unintended implications of HC use on cognition, learning, and memory.

The Relationship Between Observers' Self-Attractiveness and Preference for Physical Dimorphism: A Meta-Analysis

Background: Many studies have reported an association between observers' self-attractiveness and their preference for sexual dimorphism across different physical domains, including the face, voice, and body. However, the results of these studies are inconsistent. Here, a meta-analysis was conducted to estimate the association between observers' own attractiveness and their dimorphic preference.

Methods: Major electronic databases including PsycINFO, Web of Science, PubMed, ProQuest, and Google Scholar were searched during April 2017 (the first time) and April 2018 (the second time). The effect size computation and moderating effect analyses were conducted separately for masculine and feminine preferences.

Results: We identified 5,359 references, of which we included 25 studies (x = 55, x = number of the effect size) with 6,853 participants in the meta-analysis. Across these studies, the correlation between observers' own attractiveness and their sexual dimorphic preference was 0.095 (x = 55) and that for preference for masculinity (x = 39) and femininity (x = 16) were 0.102 and 0.076, respectively. The results of the funnel plot, Egger's regression method, and fail-safe number suggested that there was no obvious publication bias. The relationship depended on the relationship context (short or long-term), opposite or same sex (the gender of the observer and host), measures of observers' self-attractiveness (subject or objective), and preference task (e.g., attractiveness rating, forced-choice, and face sequence test). Furthermore, for female participants, using a hormonal contraceptive also influenced their masculinity preference. The effect size for the preference for a masculine body and voice was larger than that for facial masculinity.

Conclusion: We found a small but significant correlation between self-attractiveness and physical dimorphic preference, the relationship was moderated by the relationship context, same/opposite-sex, and contraceptive using. These three moderating effects represented the observer's trade-off on good genes, good provider and good father (3Gs) consistent with the life history strategies. Besides, measurement of observers' attractiveness, type of preference task and stimuli may also involve the relationship.

In situ-forming and pH-responsive hydrogel based on chitosan for vaginal delivery of therapeutic agents

One of the important routes of drug administration for localized delivery of contraceptives and cervical cancer treatment agents is vaginal canal. Due to the low pH of vagina, a pH-responsive drug delivery system was developed. This hydrogel was synthesized based on a mucoadhesive biopolymer, chitosan (CS), that promotes the interaction between the hydrogel and mucosal surface of the vagina, potentially increasing the residence time of the system. This injectable hydrogel was formed via acid-labile Schiff-base linkages between free amine groups and aldehyde functionalities on modified chitosan. A novel approach was taken to add aldehyde functionalities to chitosan using a two-step reaction. Two types of slow and fast degrading hydrogels were prepared and loaded with iron (II) gluconate dihydrate, a non-hormonal spermicide, and doxorubicin hydrochloride, an anti-cancer drug. The release profiles of these drugs at different pH environments were assessed to determine the pH-dependent release mechanism. Mechanical properties, swell-ability and degradation rate of these matrices were studied. The cross-linking density of the hydrogel as well as pH changes played an important role in the characteristic of these hydrogels. The hydrogels degraded faster in lower pH, while the hydrogel with lower cross-linking density showed longer gelation time and faster degradation rate compared to the gel with higher cross-linking density. In vitro cytotoxicity assessment of these hydrogels in 48 h indicated the non-toxic effect of these hydrogels toward mesenchymal stem cells (MSCs) in the test period.

A Study of the Impact of the Commonly Used Female Contraceptive Methods in Egypt on Female Sexual Function

Temporary methods of female contraception are commonly practiced in Egypt, but an increased total fertility rate was recently reported. Impaired female sexual function (FSF) due to contraceptive use can be a reason for irregular use/discontinuation. This study aimed at identifying the type(s) of the commonly used contraceptive method(s) in Egypt that can impair FSF. The sexual function of women on some form of temporary contraceptive was compared to that of women not using contraceptives. All participants answered the Arabic translation of the 19-item Female Sexual Function Index questionnaire. Furthermore, participants on contraceptives answered a global question: Did the use of the contraceptive impact your sexual function? Participants on contraceptives were subgrouped into Copper-T intrauterine devices (IUDs), progestin injectable (medroxyprogesterone 400 mg), combined oral pills (COP; 30 µg ethinylestradiol and 150 µg levonorgestrel), and progestin-only pills (POP; 750 µg levonorgestrel). According to this study, neither the IUDs nor the COP impaired FSF. However, the progestin-only contraceptives were associated with impairment of FSF; the injectable was worse than the POP. Accordingly, counseling about the potential sexual risks of the available contraceptive methods is recommended. Impaired FSF due to contraceptive use can be addressed by a trial of an alternative method to avoid discontinuation.

Percepciones de las Mujeres Mexicanas Sobre el Uso de Métodos Anticonceptivos

Introducción:

Más del 50% de los embarazos a nivel mundial son no planeados. El 99% de los embarazos no planeados se presentan en países en desarrollo, el 38% de estos en América Latina y el Caribe.

Métodos:

Se realizó un estudio cualitativo, a través un análisis de contenido congruente con la descripción cualitativa. Se realizaron entrevistas semiestructuradas a mujeres de 18 a 24 años de edad.

Resultados:

La angustia por un cambio de vida, el tener planes para el futuro y una relación formal mayor a un año son los principales motivos para usar un método anticonceptivo de forma correcta y consistente. Las barreras reportadas para el uso de métodos anticonceptivos fueron los efectos secundarios, las creencias de los padres acerca de la sexualidad y la reproducción y el estigma hacia las mujeres que usan métodos anticonceptivos.

Conclusiones:

Las principales barreras en las mujeres son las de tipo cultural. Los hallazgos muestran que la influencia de la red social es más importante que las creencias individuales. Por lo que se debe de incluir al personal de salud y la comunidad en las intervenciones de salud.

Prenatal levonorgestrel exposure induces autism-like behavior in offspring through ERβ suppression in the amygdala

BACKGROUND

Autism spectrum disorder (ASD) is characterized by impairments in social communication and restricted or repetitive behaviors or interests. ASD is now diagnosed in more than one out of 100 children and is biased towards males by a ratio of at least 4:1. Many possible explanations and potential causative factors have been reported, such as genetics, sex, and environmental factors, although the detailed mechanisms of ASD remain unclear.

METHODS

The dams were exposed through oral contraceptives to either vehicle control (VEH) alone, levonorgestrel (LNG) alone, ethinyl estradiol (EE) alone, or a combination of LNG/EE for 21 days during their pregnancy. The subsequent 10-week-old offspring were used for autism-like behavior testing, and the limbic tissues were isolated for analysis. In another experimental group, 8-week-old male offspring were treated by infusion of ERβ overexpression/knockdown lentivirus in the amygdala, and the offspring were analyzed after 2 weeks.

RESULTS

We show that prenatal exposure of either LNG alone or a LNG/EE combination, but not EE alone, results in suppression of ERβ (estrogen receptor β) and its target genes in the amygdala with autism-like behavior in male offspring, while there is a much smaller effect on female offspring. However, we find that there is no effect on the hippocampus and hypothalamus. Further investigation shows that ERβ suppression is due to LNG-mediated altered methylation on the ERβ promoter and results in tissue damage with oxidative stress and the dysfunction of mitochondria and fatty acid metabolism, which subsequently triggers autism-like behavior. Overexpression of ERβ in the amygdala completely restores LNG-induced ERβ suppression and autism-like behaviors in offspring, while ERβ knockdown mimics this effect, indicating that ERβ expression in the amygdala plays an important role in autism-like behavior development.

CONCLUSIONS

We conclude that prenatal levonorgestrel exposure induces autism-like behavior in offspring through ERβ suppression in the amygdala. To our knowledge, this is the first time the potential effect of oral contraceptives on the contribution of autism-like behavior in offspring has been discovered.

Decreased allopregnanolone induced by hormonal contraceptives is associated with a reduction in social behavior and sexual motivation in female rats

RATIONALE

Allopregnanolone is a neurosteroid involved in depression, memory, social, and sexual behavior. We have previously demonstrated that treatment with a combination of ethinylestradiol (EE) and levonorgestrel (LNG), two compounds frequently used in hormonal contraception, decreased brain allopregnanolone concentrations. These changes may contribute to some of the emotional and sexual disorders observed in hormonal contraceptive users.

OBJECTIVES

We thus examined whether the reduction in allopregnanolone concentrations induced by long-term EE/LNG administration was associated with altered emotional, learning, social, and sexual behaviors.

METHODS

Rats were orally treated with a combination of EE (0.030 mg) and LNG (0.125 mg) once a day for 4 weeks and were subjected to behavioral tests 24 h after the last administration.

RESULTS

EE/LNG treatment reduced immobility behavior in the forced swim test, without affecting sucrose preference and spatial learning and memory. In the resident-intruder test, EE/LNG-treated rats displayed a decrease in dominant behaviors associated with a reduction in social investigation. In the paced mating test, EE/LNG treated rats showed a reduction in proceptive behaviors, while the lordosis quotient was not affected. Progesterone, but not estradiol, administration to EE/LNG-treated rats increased sexual activity and cerebrocortical allopregnanolone concentrations. Prior administration of finasteride decreased allopregnanolone concentrations and abolished the increase in proceptivity induced by progesterone administration.

CONCLUSIONS

The decrease in brain allopregnanolone concentrations induced by EE/LNG treatment is associated with a reduction in social behavior and sexual motivation in female rats. These results might be relevant to the side effects sometimes exhibited by women taking hormonal contraceptives.

An introduction to comparative evolutionary psychology

Previously we (Vonk and Shackelford, 2012, in press) proposed an integration of comparative psychology and evolutionary psychology into a new field of "comparative evolutionary psychology." This integrative discipline incorporates principles from ethology, ecology, biology, anthropology, and psychology, broadly defined. We present in this special issue a collection of original empirical and theoretical review articles in which leading researchers propose ways to successfully integrate comparative and evolutionary approaches within their particular areas of study. We showcase the key contributions of these articles and highlight several empirical and theoretical challenges, as well as key future directions, for comparative evolutionary psychology.

An Introduction to Comparative Evolutionary Psychology

Previously we ( Vonk and Shackelford, 2012 , in press) proposed an integration of comparative psychology and evolutionary psychology into a new field of “comparative evolutionary psychology.” This integrative discipline incorporates principles from ethology, ecology, biology, anthropology, and psychology, broadly defined. We present in this special issue a collection of original empirical and theoretical review articles in which leading researchers propose ways to successfully integrate comparative and evolutionary approaches within their particular areas of study. We showcase the key contributions of these articles and highlight several empirical and theoretical challenges, as well as key future directions, for comparative evolutionary psychology.