Tapping for love: courtship, mating, and behavioral asymmetry in two aphid parasitoids, Aphidius ervi and Aphidius matricariae (Hymenoptera: Braconidae: Aphidinae).

Understanding the biology and ecology of parasitoids can have direct implications for their evaluation as biological control agents, as well as for the development and implementation of mass-rearing techniques. Nonetheless, our current knowledge of the possible influence of lateralized displays (i.e., the asymmetric expression of cognitive functions) on their reproductive behavior is scarce. Herein, we characterized the behavioral elements involved in courtship, and quantified the durations of 2 important aphid parasitoids, Aphidius ervi Haliday and Aphidius matricariae Haliday (Hymenoptera: Braconidae: Aphidiinae). We quantified the main indicators of copulation and examined the occurrence of lateralized traits at population level. Results indicated that A. matricariae exhibited longer durations of wing fanning, antennal tapping, pre-copula and copula phases compared to A. ervi. Postcopulatory behavior was observed only in A. matricariae. Unlike other parasitoid species, the duration of wing fanning, chasing, and antennal tapping did not affect the success of the mating of male A. ervi and A. matricariae. Both species exhibited a right-biased female kicking behavior at the population level during the pre-copula. Our study provides insights into the fundamental biology of aphidiine parasitoids and reports the presence of population-level lateralized mating displays, which can serve as useful benchmarks to evaluate the quality of mass-rearing systems.

A simple method for repeated in vivo sperm collection from laboratory mice.

PURPOSE: Mouse spermatozoa for archiving laboratory mice or for in vitro fertilization (IVF) are routinely obtained from the cauda epididymis of adult males sacrificed for this purpose. To avoid the death of the donor, we tested whether a precisely timed interruption of the mating act could be used for repeated sperm collection from laboratory mice. METHODS: Sperm donors (B6D2F1) were mated with a receptive female, and mating behavior was observed. The stud was separated from the female 1-2 s after the onset of the ejaculatory shudder. The ejected copulatory plug with the yellowish viscous ejaculate was carefully removed from the penile cup. RESULTS: A total of 80 ejaculates were successfully obtained from 100 ejaculations. The latency to first mount was 1.1 ± 1.1 min (mean ± SD) and to ejaculation 8.1 ± 4.7 min. The average number of mounts to ejaculation was 10.5 ± 5.8, and the mean number of spermatozoa per collected ejaculate was 1.86 ± 1.05 × 106. An average fertilization rate of 76% was observed after IVF. CONCLUSIONS: Separating the stud from the female just before ejaculation is feasible, easy to learn, and requires no special equipment. The sperm count of collected ejaculates is lower than natural ejaculations, but higher than previous in vivo sperm collection methods achieved. We recommend this simple sperm collection method in mice, especially when the donor cannot be sacrificed and/or repeated sperm collection from the same animal is required for experimental purposes.

Influence of the COVID-19 pandemic on births and induced abortions in Southern Sweden: a register-based study.

BACKGROUND: Pandemics are linked with declining birth rates, but little is known about how the COVID-19 pandemic has influenced childbearing decisions. We aimed to investigate the associations between the COVID-19 pandemic and reproductive decisions, specifically to identify potential changes in the frequency of deliveries and induced abortions in Skåne, Sweden. METHODS: Using the Skåne Healthcare Register, we identified women aged 15-45 years who had at least one pregnancy-related care visit registered between 1 January 2013 and 11 November 11 2021. Deliveries and induced abortions were identified, and changes in weekly delivery and abortion counts were assessed using an interrupted time series design. Relative risks (RRs) and 95% confidence intervals (CIs) were estimated from a Poisson regression model. RESULTS: During the study period we identified 129 131 deliveries and 38 591 abortions. Compared with the counterfactual (exposed interval assuming COVID-19 had not occurred), pandemic exposure was associated with fewer deliveries (RR 0.93; 95% CI 0.89 to 0.98). For abortions, pandemic exposure appeared to be associated with fewer abortions (RR 0.95; 95% CI 0.90 to 1.00); however, age-related differences were found. Among women aged 25 years and over, pandemic exposure was more strongly associated with fewer abortions. Contrastingly, among women aged under 25 years, abortions appeared to increase. CONCLUSIONS: The COVID-19 pandemic seemed to have contributed to a decline in births in Southern Sweden. During the same period, abortions declined in women in the older age range, but contrastingly increased among younger women.

Relationship between reproductive health literacy and components of healthy fertility in women of the reproductive age.

BACKGROUND AND AIM: One of the key factors affecting women's behavior with fertility issues is their health literacy, but this topic has been less addressed in the existing studies. We aimed to determine the relationship between reproductive health literacy and components of healthy fertility in women of reproductive age. MATERIALS AND METHODS: This cross-sectional study was conducted from March 2019 to September 2014 on 230 married women who were referred to comprehensive health centers in Lordegan city. Data were collected using a reproductive health literacy questionnaire, demographic and fertility information checklist, and components of healthy fertility. Data analysis was done using SPSS software, version 20. Pearson, Spearman, and independent t-tests were used as appropriate. RESULTS: The mean ± SD reproductive health literacy score in the participants was 43.80 ± 18.99 depicting an average literacy level in more than half of the women. Also, the reproductive health literacy score had a statistically significant relationship with the use of low-failure contraceptive methods (P < 0.001) and planned pregnancy (P = 0.03). However, this relationship was not significant regarding pre-pregnancy care (P = 0.88) and observing the interval between pregnancies (P = 0.57). CONCLUSION: We found a relationship between the level of reproductive health literacy and the use of family planning methods with low failure and planned pregnancy. Hence, it seems that interventions to improve reproductive health literacy are effective in reducing the occurrence of high-risk pregnancies and unwanted and unplanned pregnancies. Therefore, it is suggested that the health system consider and provide education related to reproductive health literacy as a part of healthy reproductive services.

Exceptional Early Jurassic fossils with leathery eggs shed light on dinosaur reproductive biology.

Our understanding of pre-Cretaceous dinosaur reproduction is hindered by a scarcity of evidence within fossil records. Here we report three adult skeletons and five clutches of embryo-containing eggs of a new sauropodomorph from the Lower Jurassic of southwestern China, displaying several significant reproductive features that are either unknown or unlike other early-diverging sauropodomorphs, such as relatively large eggs with a relatively thick calcareous shell formed by prominent mammillary cones, synchronous hatching and a transitional prehatching posture between the crocodilians and living birds. Most significantly, these Early Jurassic fossils provide strong evidence for the earliest known leathery eggs. Our comprehensive quantitative analyses demonstrate that the first dinosaur eggs were probably leathery, elliptical and relatively small, but with relatively long eggshell units, and that along the line to living birds, the most significant change in reptilian egg morphology occurred early in theropod evolution rather than near the origin of Aves.

Expression patterns and behavioral effects of conopressin and APGWamide in the nudibranch Berghia stephanieae.

The highly conserved oxytocin/vasopressin family of nonapeptides plays many roles across the animal kingdom, from osmoregulation to reproductive physiology. We investigated the expression patterns and pharmacological effects of the gastropod ortholog of this peptide, conopressin, along with another peptide involved in gastropod reproduction, APGWamide, in the nudibranch Berghia stephanieae. A brain transcriptome was used to identify and annotate the gene sequences for the peptides and one conopressin receptor. In-situ hybridization chain reaction showed that many neurons in the brain expressed these peptides. However, the peptide genes were co-expressed by only three neurons, which were in the right cerebral ganglion, the same side on which the reproductive organs are located. A conopressin receptor (BSCPR1) was expressed in a prominent population of APGWamide expressing neurons. Placing animals in a solution containing the APGWamide peptide caused minimal behavioral changes. However, exposure to conopressin reduced locomotion, increased gut contractions, and caused voiding at high concentration. The genes for these peptides and BSCPR1 were expressed in cells in the digestive system. BSCPR1 was also expressed by a line of neurons on the anterior portion of the radula and would be contacted during feeding. APGWamide-expressing neurons were found in the genital ganglion. All three genes expressed in cells on sensory appendages. These results are consistent with the conopressin playing a variety of roles in the brain and the body and being involved in both reproduction and digestion. This study sheds light on the function of this ancient nonapeptide in a new-to-neuroscience invertebrate species.

Japanese honey bees (Apis cerana japonica) have swarmed more often over the last two decades.

The impacts of temperature increase are a concern for honey bees, which are major pollinators of crops and wild plants. Swarming is the reproductive behavior of honey bees that increases colony numbers. Honey bee colonies sometimes swarm multiple times, with each swarming termed a "swarming event" and a series of these events called a "swarming cycle." The number of swarming events per swarming cycle varies widely depending on climatic conditions and subspecies, and the recent temperature increase due to global warming might be affecting the number of swarming events per swarming cycle of native honey bees. We clarified long-term changes in the number of swarming events per swarming cycle of Japanese honey bees (Apis cerana japonica) by collecting beekeepers' swarming logbooks. The survey showed that between 2000 and 2022, Japanese honey bees swarmed 1 to 8 times per swarming cycle. Generalized linear model analysis indicated that year had a significant positive effect (coefficient, 0.03; 95% CI, 0.01-0.04); that is, the number of swarming events per swarming cycle showed a moderate increase over time. In addition, we found that colonies swarmed more often in a cycle when the swarming process began in early spring, especially in March. Considering the notably strong trend in Japan of warmer temperatures in March, the number of swarming events per swarming cycle may be increasing because reproduction is beginning earlier in the year. Further analyses are needed to verify the causal relationship of temperature increase on the number of swarming events per swarming cycle.

Independent and synergistic effects of microplastics and endocrine-disrupting chemicals on the reproductive social behavior of fathead minnows (Pimephales promelas).

Microplastics (MPs) have become an environmental concern in recent years, with most research focused on the physiological effects of exposure. Comparatively little consideration has been given to the potential behavioral impacts of exposure, which may also have fitness consequences for individuals. Moreover, MPs can serve as vectors for endocrine-disrupting chemicals and other locally co-occurring contaminants known to impair behavioral responses. This project aimed to determine whether MPs alone or in association with a common environmental EDC (17-alpha ethinyl estradiol; EE2) alter reproductive behavior and decision-making in fish. Male and female fathead minnows (Pimephales promelas) were exposed to MPs associated with either a low (10 ng/L; MPEE2 10) or high (50 ng/L, MPEE2 50) concentration of EE2, or MPs without EE2 (MPvirgin) for 30 days via a dietary feeding protocol. Behavioral trials were conducted on Day 31 to determine the effects of exposure on male-female social interactions. The expression of male sexually selected traits, including courtship, was unaffected by exposure. However, non-exposed females in all treatment groups trended toward discrimination against exposed males, which reached statistical significance for the MPEE2 50 group. Female fish exposed to MPs, alone or in association with EE2, were equally likely to approach and associate with non-exposed and exposed males. The results from this study suggest that MPs may alter social behavior in fishes and that the behavioral impacts of exposure may be more strongly pronounced in females than males. Such individual-level changes in fitness have the potential to impact population size, with downstream effects on the broader aquatic community.

Ritualized ink use during visual courtship display by males of the sexually dimorphic cuttlefish Sepia andreana.

Visual display is a crucial aspect of courtship, and their success relies on both display quality and the surrounding environment, such as the visual background. Cephalopods may release ink when attacked by predators or during aggressive interactions with conspecifics. Here, we report that ink is used as a part of the courtship display by males of the cuttlefish species Sepia andreana. Males of this species engage in a highly ritualized multimodal courtship using a pair of markedly long sexually dimorphic arms. At the climax of the courtship, the male releases a diffuse backdrop of ink near himself and then performs the specific courtship display by extending his sexually dimorphic arms and altering his body pattern to pale in front of this ink backdrop, and then proceeds to mate. This novel use of cephalopod ink could make the surroundings darker and more homogeneous, potentially serving as a temporary modification of the visual environment for courtship display.

Reproductive Seasonality, Estrous Cycle, Pregnancy, and the Recurrence of Postpartum Estrus Based on Long-Term Profiles of Fecal Sex Steroid Hormone Metabolites regarding Zoo-Housed Female Golden Takins (Budorcas taxicolor bedfordi).

This study investigates the non-invasive monitoring of the endocrine ovarian activities of captive female golden takins (Budorcas taxicolor bedfordi) based on long-term fecal sex steroid hormone metabolite dynamics. Fecal progesterone (P4) metabolite dynamics were monitored in nine females for 0.5-15 years between 2004 and 2022. Fecal estradiol-17ß (E2) and estrone (E1) metabolites were measured during certain estrous cycles, and fecal E1 metabolite concentrations were measured during all gestation periods. The breeding season of the captive animals was mainly between May and December, and they were polyestrous animals whose breeding season begins during the long-day period. The onset of the breeding season occurred slightly earlier as age increased. The mean age (±SD) at puberty based on fecal P4 metabolite dynamics was 4.1 ± 2.9 years. The first conception ages ranged from 2.3-10.2 years. The mean estrous cycle period (±SEM) was 25.4 ± 1.1 days, and mounting and mating occurred in periods of low fecal P4 metabolite levels during the breeding season. The mean gestation period (±SD) from the estimated mating date to the calving date was 253.9 ± 5.7 days, and the fecal P4 metabolite distribution during pregnancy was bimodal. Fecal estrone metabolite levels gradually increased 21 weeks before delivery, peaked during the week of delivery, and then markedly decreased in the first week after delivery. Estrus resumed in the first April-August period after delivery (mean ± SD; 103.5 ± 40.9 days) or in May of the year after delivery (421.0 ± 16.5 days). This study revealed that the estrous cycle and pregnancy of female golden takins can be determined by fecal progesterone metabolite dynamics and that fecal estrone metabolite dynamics increases toward parturition and are useful for predicting the date of delivery. This endocrinological information is important for planned breeding efforts for the golden takins.

A systematic review of the childbearing needs of single-child couples.

BACKGROUND: Nowadays, the challenge of having single child is spreading in many countries. Only- child family is prevalent in 26% of families in Canada, 21% in the United States, 47.5% in Europe and 20% in Iran, which can lead to fertility below replacement level. Therefore, the current review was conducted to identify the needs of single-child couples. METHODS: The PRISMA checklist was used to prepare this systematic review report. English and Persian articles published between 2000 and April 2023 were searched in the English databases of ISI, PubMed, Cochrane library and Google Scholar search engine as well as Persian databases of SID and Magiran using keywords of only child, needs assessment and Reproductive behavior. All cross-sectional and correlational studies that addressed the needs of single-child couples were included in the study. The quality assessment of the articles was done by the STROBE checklist. Data extraction was done by two independent researchers using a self-structured checklist. To analyze the data, following tabulating the extracted data, the process of qualitative synthesis was done for systematic review taking into account ethical considerations. RESULTS: Out of 1,581 articles found, 17 articles were included in the systematic review. The needs of single-child couples were divided into four general areas included 1) Financial needs, 2) Cultural needs, 3) Educational needs, and 4) Supportive needs. The support needs included two kinds of social and family support. CONCLUSION: Solving financial needs, creating a culture of positive values of childbearing and men's participation in household affairs, considering women's preferences in order to increase education and employment, childbearing training and counseling and creating social and family support in line with work and family harmony and quality care of children, as the most important needs of single-child couples, should be incorporated in the formulation of childbearing incentive programs.

[The social hygienic aspects of reproductive behavior of women aged 40-45 years].

In the context of forecasted decreasing of natality, actuality of studying its causes for organizational decision-making increases. The purpose of the study was to determine factors affecting reproductive behavior of women aged 40-45 years residing in areas with different natality levels in 2020-2021. The cohort, analytical, sociological methods were applied. The results of study demonstrated that in areas with high natality level most of urban women with higher education and high income resides in conditions of dormitory or mortgage flat and working in profile of their specialty. They are characterized by belated marriage that results in postponed child-bearing. The areas with low natality are characterized by dwelling of rural women with secondary or secondary specialized education. They reside in their own homes and work in other occupations than their specialty. The analysis of social status of women of different age groups will permit more selective approach in developing measures of increasing natality in modern conditions.

Neural control of reproduction in reptiles.

Reptiles display considerable diversity in reproductive behavior, making them great models to study the neuroendocrine control of reproductive behavior. Many reptile species are seasonally breeding, such that they become reproductively active during their breeding season and regress to a nonreproductive state during their nonbreeding season, with this transition often prompted by environmental cues. In this review, we will focus on summarizing the neural and neuroendocrine mechanisms controlling reproductive behavior. Three major areas of the brain are involved in reproductive behavior: the preoptic area (POA), amygdala, and ventromedial hypothalamus (VMH). The POA and VMH are sexually dimorphic areas, regulating behaviors in males and females respectively, and all three areas display seasonal plasticity. Lesions to these areas disrupt the onset and maintenance of reproductive behaviors, but the exact roles of these regions vary between sexes and species. Different hormones influence these regions to elicit seasonal transitions. Circulating testosterone (T) and estradiol (E2) peak during the breeding season and their influence on reproduction is well-documented across vertebrates. The conversion of T into E2 and 5α-dihydrotestosterone can also affect behavior. Melatonin and corticosterone have generally inhibitory effects on reproductive behavior, while serotonin and other neurohormones seem to stimulate it. In general, there is relatively little information on the neuroendocrine control of reproduction in reptiles compared to other vertebrate groups. This review highlights areas that should be considered for future areas of research.

Associations between the COVID-19 pandemic and women's fertility intentions: a multi-country, cross-sectional (I-SHARE) study.

INTRODUCTION: The COVID-19 pandemic, together with the subsequent social distancing measures, could lead to shifts in family and fertility planning. This study aimed to explore the associations between the COVID-19 pandemic and changes in fertility intentions among an international sample of reproductive-aged women. METHODS: A multi-country, cross-sectional study based on data from 10 672 women aged 18-49 years who participated in the International Sexual Health And REproductive Health (I-SHARE) study, which organised an international online survey between July 2020 and February 2021. Factors associated with changes in fertility intentions were explored using multinomial probit regression models. Cluster-robust standard errors were used to calculate model parameters. RESULTS: Of 10 672 included reproductive-aged women, 14.4% reported changing their fertility intentions due to the pandemic, with 10.2% postponement and 4.2% acceleration. Women who had ever been isolated/quarantined were more likely to postpone their fertility intentions (adjusted odds ratio (AOR)=1.41; 95% CI 1.18 to 1.69) compared with those who had not; women who lived with a steady partner were more likely to want children sooner (AOR=1.57; 95% CI 1.10 to 2.23) compared with those who did not; and those who reported a higher frequency of getting angry, feeling frustrated, or worrying about their finances were more likely to postpone their fertility intentions. The main findings were robust in the sensitivity analyses. CONCLUSIONS: Most women who changed fertility intentions because of the pandemic have postponed intentions to expand their families. The pandemic-induced exposures were associated with these postponements.

Selected Aspects of Reproductive Behavior of American Mink (Neovison vison) under Artificial Conditions.

Observation and behavioral analysis of animals can be one of the factors taken into consideration when assessing the welfare of animals kept in artificially created breeding conditions. Disturbed welfare and prolonged exposure to stress can lead to the emergence of abnormal behaviors, including reproductive issues. The aim of this study was to examine the mating behavior of male American mink, with regard to the duration of mating and any potential differences with regard to time of day, mating period, number of mating attempts, and time spent with the female. The study material consisted of 12 one-year-old male American minks with pearl coloring and 60 two-year-old females. Observations were conducted using images captured using externally mounted cameras. The video material capturing the activity of males and females during the mating period was analyzed using the Behawior program. The obtained results indicate the presence of individual differences in copulation duration. It was observed that the copulation time increases with successive days of the breeding season and with number of copulations. It was also observed that a longer time spent with the female to initiate copulation, and behaviors such as rubbing or sniffing the female, were associated with a shorter copulation time. The above-mentioned studies provide specific guidelines regarding the management of matings on the farm, demonstrating the feasibility of conducting matings both in the hours before and after noon.

MAIN PROBLEMS AFFECTING THE FORMATION OF THE WELL-BEING OF YOUNG RUSSIAN FAMILIES: ACCORDING TO THE RESULTS OF THE ALL-RUSSIAN SOCIOLOGICAL RESEARCH.

The paper presents the findings of a study conducted using a mass questionnaire survey of members of young families (n = 893). The purpose of the study is to identify what problems affecting well-being are faced by members of young families. In the sample, young families are represented by two groups - families with children and families without children. It was revealed that the assessment of the significance of problems in family life is different in families with children and childless families, including the number of children in the family that affects the situation. Ratings of family problems were built according to the following criteria - self-assessment of men and women and parenting experience. It is concluded that, according to a number of criteria (both material and non-material), well-being is formed.

Contrasting Effects of Leaf Litter Quality and Diversity on Oviposition of Mosquitoes.

The quality and diversity of leaf litter are important variables in determining the availability of energy in detritus-based food webs. These factors can be represented by the stoichiometric proportion between carbon and multiple nutrients, and the mixture of litter from different taxonomic and/or functional origins. In aquatic ecosystems, factors that accelerate litter decomposition can influence the secondary productivity of planktonic microbiota, which act as a link between litter and higher trophic levels. This study aimed to analyze the influence of litter quality and diversity on the oviposition behavior of medically important mosquitoes. We hypothesized that both factors would have a positive effect on the attraction of female mosquitoes and would stimulate a greater amount of oviposition. To test this hypothesis, microcosms containing isolated leaf litter leachates from four plant species were used to manipulate gradients of litter quality, and microcosms with all leachates combined were used to test the effects of litter diversity. The results showed a positive effect of litter quality (p < 0.05) on mosquito oviposition rate, with lower C:P ratio litter species (high-quality litter) presenting higher oviposition rates than litter species with high C:P ratios (low-quality litter). However, contrary to our expectations, litter diversity had a negative effect (p = 0.002) on the magnitude of egg-laying by mosquitoes. Our results highlight the importance of litter quality and diversity for insect reproductive behavior. Our data shows that litter quality can serve as a crucial indicator of a suitable environment utilized by female mosquitoes for oviposition. This finding can enhance our ability to understand and develop effective methods for mitigating the reproduction of medically significant mosquitoes, whether by allowing us to predict, based on the composition of vegetation species, areas more prone to mosquito infestation, or by using high-quality litter in oviposition traps. Furthermore, maintaining vegetation diversity can help control mosquito reproduction.

Unpacking the Impact of Early Adverse Childhood Experiences on Early Onset of Sexual Intercourse Among an Urban Birth Cohort of Early Adolescents.

PURPOSE: Early adverse childhood experiences (ACEs) predict early onset of sexual intercourse. However, patterns of ACEs identified using latent class analysis (LCA) and their links to early sexual intercourse have been less examined. In this study, we apply LCA to identify ACEs profiles at age five and to examine whether these profiles differentially predict adolescents' sexual initiation. METHODS: We analyzed data obtained from the Future of Families and Child Wellbeing Study for 3,185 participants (male = 1,638; female = 1,547). This included parental/caregivers' reports of 10 types of ACEs when participants were on average at age five and youth self-report data on sexual intercourse before or at age 15. We used LCA to classify the participants into subgroups and multinomial logistic regressions to examine differences in early sexual initiation among the ACEs subgroups. RESULTS: LCA showed evidence of four classes for both genders: low adversity (51.8%), socioeconomic adversity (32.0%), family dysfunction (12.0%), and abuse (4.2%). We found class membership differences in early sexual intercourse in all three adversity classes compared to the low adversity group. Pairwise comparison tests further revealed that adolescents in the family dysfunction class had lesser odds of engaging in early sexual intercourse than their counterparts in the socioeconomic adversity and abuse classes. DISCUSSION: Our findings suggest that LCA could help identify meaningful and distinctive child adversity patterns while accounting for the co-occurrence of ACEs. This is particularly helpful in evaluating who might be at greatest health risk which can further inform more effective and targeted interventions.

[Matrimonial behavior of student youth in the context of social health studying (gender aspect)].

The article presents the results of a research work aimed at identifying the features of the matrimonial behavior of students in the aspect of social health studying. Of particular importance is the study of students' value attitudes towards marriage and family in a gender context. The authors conducted an empirical study on the basis of the National Research University «BelSU¼ (n = 267; proportional selection based on gender, age, course, level and form of education). The analysis of the main marital attitudes of this group (attitude towards marriage, readiness for marriage, criteria for choosing a marriage partner, motives for marriage, reproductive behavior, reproductive health) was carried out on the basis of primary data obtained during a survey of students of the Belgorod State National Research University. It was revealed that most of the students of NRU «BelSU¼ have a traditional idea of marriage, have a desire to marry and start a family, students prefer official marriage, which implies traditional family values, which characterizes positive trends in the formation of social health. When choosing a marriage partner, most young people are guided by the personal characteristics of a person and their value orientations. It was revealed that the formation of the students' social health, among other aspects, is due to the orientation towards the established values in relation to the value of marriage and the socio-cultural norms of matrimonial behavior.

Contraceptive Behavior Dynamics and Unintended Pregnancy: A Latent Transition Analysis.

The average U.S. woman wants to have two children; to do so, she will spend about three years pregnant, postpartum, or trying to become pregnant, and three decades trying to avoid pregnancy. However, few studies have examined individual patterns of contraceptive use over time. These trajectories are important to understand given the high rate of unintended pregnancy and how little we know about the complex relationship between contraceptive use, pregnancy intention, and patterns of reproductive behavior. We use data from the 2015-2017 National Survey of Family Growth to examine reproductive behavior and pregnancies across three years of calendar data. We identify seven behavior typologies, their prevalence, how women transition between them, and how pregnancies affect transitions. At any given time, half of women are reliably using contraception. A small proportion belong to a high pregnancy risk profile of transient contraceptive users, but some transition to using condoms or other methods consistently. An unintended pregnancy may initiate a transition into stable contraceptive use for some women, although that is primarily condom use. These findings have important implications for the ways contraception fits into women's lives and how that behavior interacts with relationships, sex, and life stage trajectories.