Hormonal Contraception Use and Sexual Frequency across Young Women's Intimate Relationships.

We examined whether hormonal contraception (HC) use predicts sexual frequency throughout and across young women's intimate relationships. From 2008-2012, the Relationships Dynamics and Social Life Study collected weekly surveys over 2.5 years, and included 893 women (aged 18-19 at baseline) who reported 2,547 intimate relationships across 32,736 weeks. Three-level logistic multilevel models assessed the weekly probability of sexual intercourse based on 1) weekly HC use (vs. nonuse) and 2) duration of HC use, both accounting for several relational and individual characteristics, including relationship duration. Women had more frequent sexual intercourse when they were using HC than when they were not (predicted probabilities .65 vs .41). The weekly probability of sexual intercourse increased sharply within the first month of HC initiation (by about 27 percentage points), remained high for several months, then began to slowly decline (yet remained above that of nonuse). When separated by method type, similar trajectories were found for the pill, ring, and IUD/implant; following the initial increase, steeper declines in intercourse frequency were found for the contraceptive injectable, eventually dropping below pre-initiation levels. Findings signify the immediate influence of reduced pregnancy fears in facilitating sexual intercourse among young women, which may decline as HC use continues long-term.

The Dynamics of Intimate Relationships and Violent Victimization Among Young Women.

Despite the fact that intimate partner violence (IPV) occurs within intimate relationships, we know relatively little about the characteristics of those intimate relationships, and even less about how IPV changes across time within different relationships. We use the Relationship Dynamics and Social Life (RDSL) study, based on a random sample of 1003 18-19-year-old women residing in a Michigan county. Women were interviewed weekly for 2.5 years, resulting in an age range of 18 through 22. We estimate hybrid "within-between" regression models, which allows us to directly compare the same woman's risk of experiencing IPV across her different relationships, varied in terms of resources, balance of power, conflict, childbearing, relationship type, and duration. Our analyses demonstrate that power imbalance in intimate relationships, non-monogamous and unstable relationships, relationships with men who are not the father of a woman's existing children, and serious relationships (especially stayover and cohabiting) place young women in their late teens and early twenties at particularly high risk of multiple dimensions of IPV. Our fixed-effects modeling strategy isolated the increase in IPV risk that is due to these characteristics and experiences within intimate relationships from the risk due to young women being at high risk of IPV for other reasons who might tend to choose these types of relationships. The elevated risk of IPV in relationships with these characteristics and experiences supports a causal link between them. Our research supports the potential efficacy of interventions that reduce conflict, equalize power within relationships, and encourage women-especially young mothers-to delay serious relationships.

Mechanisms Linking High Residential Mobility to Decreased Contraceptive Use: The Importance of Method Availability.

While research has demonstrated that high residential mobility has negative consequences for an array of outcomes, particularly among women and young adults, the mechanisms underlying these associations are unclear. The consequences of high residential mobility may be comprised solely of a series of short-term disruptions surrounding individual moves, or there may also be long-term, cumulative effects from repeated moves. High residential mobility may diminish access to resources as individuals move to different neighborhoods, impose a cognitive burden that impairs their ability to plan ahead, or decrease the relative power they have in their relationships to limit exposure to risk behaviors. We adjudicate between these possibilities by predicting the effects of high residential mobility on sexual intercourse and contraceptive use, the proximate determinants of pregnancy, during women's transition to adulthood. Using 2.5 years of monthly address data for 882 respondents in the Relationship Dynamics and Social Life study-a random sample of young women in Genesee County, Michigan-we find that high residential mobility is associated with long-term decreases in contraceptive use. These long-term consequences are independent of the short-term effects of individual moves and attributable to diminished contraceptive access. We disentangle the effects of home-leaving, which is distinct from subsequent moves.

Sexual Intercourse Frequency During Pregnancy: Weekly Surveys Among 237 Young Women From A Random Population-Based Sample.

BACKGROUND: Significant differences in sexual frequency during pregnancy have been documented in cross-sectional and once-per-trimester longitudinal studies, with the highest sexual frequency in the first trimester and the lowest in the third trimester. However, changes in sexual frequency may be more complex than these comparisons suggest; patterns of sexual frequency have not been assessed using frequent (e.g., weekly) assessments throughout a woman's pregnancy. AIM: To assess changes in the frequency of sexual intercourse across all weeks of pregnancy. METHODS: We used data from 237 women (54% White; 43% Black) who reported a pregnancy during the Relationship Dynamics and Social Life (RDSL) study. RDSL was based on a random population-based sample of 992 women in the United States, aged 18 or 19, who completed a baseline interview and brief weekly follow-up surveys for 2.5 years. We used generalized multilevel modeling to fit and compare linear, quadratic, and piecewise (via b-splines) models. OUTCOME: Weekly probability of sexual intercourse. RESULTS: Sexual intercourse frequency clearly declined across pregnancy, yet the pattern followed the course of common pregnancy symptomology (i.e., nausea, fatigue) more closely than trimester cutoffs. The best fitting model demonstrated that the probability of sexual intercourse declined sharply (∼18% each week) between conception and 11 weeks, subsequently increased by ∼3% each week between weeks 11 and 21, and then declined steadily (∼6% each week) through the end of pregnancy. CLINICAL TRANSLATION: Documenting more precise patterns of change in sexual frequency during pregnancy provides important information to many who wish to maintain sexual intimacy while pregnant, or to those who would otherwise find the sexual disruptions particularly challenging. STRENGTHS & LIMITATIONS: This study is the first to document changes in sexual intercourse frequency throughout all weeks of pregnancy as they naturally occurred among a representative sample of young women. The focus on sexual intercourse limits the findings to only one aspect of human sexuality. The narrow age range of the sample precludes generalization to all pregnant women. CONCLUSION: Changes in sexual frequency are more complex than the general declines suggested by other studies; within-trimester patterns reveal the shortcomings in understanding sexual behavior changes when aggregated by trimester, such as severely underestimating the degree of fluctuation in the first trimester. Pregnancy symptomology may be most favorable to intercourse towards the end of the first and beginning of second trimesters, and least favorable near the end of the pregnancy. Shari M. Blumenstock, Jennifer S. Barber. Sexual Intercourse Frequency During Pregnancy: Weekly Surveys Among 237 Young Women From A Random Population-Based Sample. J Sex Med 2022;19:1524-1535.

Effects of caffeinated energy drinks on cardiovascular responses during exercise in healthy adults: a systematic review and meta-analysis of randomized controlled trials.

The impact of caffeinated energy drinks (CEDs) on the cardiovascular (CV) response to exercise has not been well described. A systematic review and meta-analysis was conducted on the acute effects of CEDs on CV responses during dynamic, aerobic exercise in 296 healthy adult males (224) and females (72) in 21 randomized controlled trials. During exercise, there was an increase in heart rate (HR) (mean difference (MD), 2.86 bpm, 95% CI, 2.39-3.34 bpm, I2 = 0%, p < 0.00001), and systolic blood pressure (SBP) (MD, 9.02 mm Hg, 95% CI, 4.25-13.79 mm Hg, I2 = 0%, p = 0.0002) with consumption of CEDs, compared with controls, but diastolic blood pressure was similar. Insufficient data were available to evaluate rate pressure product (HR × SBP) and exercise-induced arrhythmia. Though changes to HR during exercise were modest, the significant increase in exercise SBP highlights the importance of directly assessing CV effects of CEDs with exercise, especially in individuals prone to hypertension. Novelty: Exercise SBP in healthy adults is significantly increased during exercise with the consumption of CEDs compared with controls, despite limited data. The direct assessment of CV effects of CEDs with exercise highlights the particular relevance to individuals prone to hypertension.

Changes in pregnancy desire after a pregnancy scare in a random sample of young adult women in a Michigan county.

OBJECTIVES: We examined whether and how long young women became more or less likely to desire a pregnancy after experiencing a "pregnancy scare." STUDY DESIGN: We used data from the Relationship Dynamics and Social Life (RDSL) study, based on a random, population-based sample of 992 young women from a county in Michigan. They were interviewed weekly for 2.5 years. We used fixed-effects logistic regression models to predict pregnancy desire after a pregnancy scare. RESULTS: Of the 759 sexually experienced women we analyzed, 103 (14%) experienced 128 pregnancy scares. A woman's (adjusted) odds of desiring a pregnancy were 3.70 (95% CI 2.27-6.02) times higher during the week after, 3.04 (95% CI 2.30-4.10) times higher during the month after a pregnancy scare, and 2.31 (95% CI 1.71-3.11) times higher during all weeks after the pregnancy scare, compared to her other weeks during the study period. In a final model directly comparing each period to all weeks before the pregnancy scare, the odds of pregnancy desire were highest (aOR 5.08, 95% CI 3.06-8.42) during the first week, slightly smaller (aOR 3.01, 95% CI 2.11 - 4.30) during the subsequent three weeks, and remained elevated (aOR 1.58, 95% CI 1.19-2.09) throughout the remainder of the study period. CONCLUSIONS: Our analyses suggest that the experience of a pregnancy "scare" does not scare young women away from wanting pregnancies. On the contrary, the state of possibly being pregnant actually made young women in our study more likely to want to be pregnant, on average. IMPLICATIONS: Very few young women desire a pregnancy during the transition to adulthood; however, a salient life event like a pregnancy scare can abruptly generate a desire for pregnancy. Our study contributes to efforts to help women implement their pregnancy desires by furthering our understanding of those desires and the contexts in which they are formed.

Caffeinated energy drinks in the Canadian context: health risk assessment with a focus on cardiovascular effects.

In Canada, caffeinated energy drinks (CEDs) currently sold under Temporary Marketing Authorizations must meet strict eligibility criteria. These criteria, which include compositional and labelling requirements, were developed based on the outcome of a health risk assessment conducted by Health Canada (HC) in 2013. HC updated its assessment by reviewing new information with the focus on potential cardiovascular effects associated with the consumption of CEDs available for sale in Canada. Due to limited data on CED consumption among Canadians to derive accurate exposure information, the composition of a typical CED was characterized to assess the potential effects of single ingredients and synergistic interactions between ingredients on the cardiovascular system. Surveillance data on potential adverse effects related to CED consumption was also analyzed. After extensive review, HC's updated assessment confirms the current risk management approach for CEDs is health protective for Canadian consumers, including the potential for cardiovascular effects. The available evidence supports that moderate consumption (up to 500 mL per day) of a typical CED authorized for sale in Canada is safe for the general population of healthy adults and adolescents. It also re-confirms that vulnerable sub-populations (i.e., children, pregnant and/or breastfeeding women, and caffeine-sensitive individuals) should not consume CEDs. Novelty: Consumption up to 500 mL per day of a typical CED is not associated with an increased risk of cardiovascular effects. Children, pregnant and/or breastfeeding women, and caffeine-sensitive individuals should not consume CEDs.

How Nearby Homicides Affect Young Women's Pregnancy Desires: Evidence From a Quasi-Experiment.

Leveraging spatiotemporal variation in homicides that occurred during a 2.5-year weekly panel survey of 387 women ages 18-22 in Flint, Michigan, we investigate how young women's desires to become pregnant and to avoid pregnancy evolve in response to local homicides during the transition to adulthood. To address the endogeneity of exposure, we explore how the same woman's pregnancy desires (1) differed, on average, across weeks before and after the first homicide occurred within a quarter mile of her home; (2) evolved in the aftermath of this initial homicide exposure; and (3) changed in response to additional nearby homicides. One-fifth (22%) of women were exposed to a nearby homicide at least once during the study, and one-third of these women were exposed multiple times. Overall, the effects of nearby homicides were gradual: although average desires to become pregnant and to avoid pregnancy differed after initial exposure, these differences emerged approximately three to five months post-exposure. Repeated exposure to nearby homicides had nonlinear effects on how much women wanted to become pregnant and how much they wanted to avoid pregnancy. Together, our analyses provide a new explanation for why some young women-especially those who are socially disadvantaged-desire pregnancy at an early age.

Black-White Differences in Pregnancy Desire During the Transition to Adulthood.

This article explores race differences in the desire to avoid pregnancy or become pregnant using survey data from a random sample of 914 young women (ages 18-22) living in a Michigan county and semi-structured interviews with a subsample of 60 of the women. In the survey data, desire for pregnancy, indifference, and ambivalence are very rare but are more prevalent among Black women than White women. In the semi-structured interviews, although few women described fatalistic beliefs or lack of planning for future pregnancies, Black and White women did so equally often. Women more often described fatalistic beliefs and lack of planning when retrospectively describing their past than when prospectively describing their future. Using the survey data to compare prospective desires for a future pregnancy with women's recollections of those desires after they conceived, more Black women shifted positive than shifted negative, and Black women were more likely to shift positive than White women-that is, Black women do not differentially retrospectively overreport prospectively desired pregnancies as having been undesired before conception. Young women's consistent (over repeated interviews) prospective expression of strong desire to avoid pregnancy and correspondingly weak desire for pregnancy, along with the similarity of Black and White women's pregnancy plans, lead us to conclude that a "planning paradigm"-in which young women are encouraged and supported in implementing their pregnancy desires-is probably appropriate for the vast majority of young women and, most importantly, is similarly appropriate for Black and White young women.

The Dynamics of Intimate Relationships and Contraceptive Use During Early Emerging Adulthood.

We investigate the immediate social context of contraceptive behaviors: specifically, the intimate relationship. We use the Relationship Dynamics and Social Life (RDSL) study (2008-2012), based on a random sample of 1,003 women ages 18-19 residing in a Michigan county. Women were interviewed weekly for 2.5 years, resulting in an age range of 18-22. We test three sets of hypotheses about change over time within a relationship, using relationship-level within-between models, which compare a couple's contraceptive behaviors across different times in the relationship. First, we find that a couple is less likely to use contraception when the relationship is more intimate and/or committed and that a couple becomes less likely to use contraception over time, regardless of intimacy and commitment. Second, we find that a couple using contraception becomes increasingly likely to choose hormonal over coital methods, but this change occurs as a relationship endures and is unrelated to intimacy and/or commitment. Third, we find that a condom-using couple's consistency does not decline when there is conflict; rather, consistency of condom use declines over time regardless of the relationship's characteristics. We also demonstrate that conflict and power imbalance increase reliance on hormonal methods among those using contraception; conflict decreases consistency among withdrawal (but not condom) users; and nonmonogamy increases reliance on condoms and decreases withdrawal consistency. The strong and consistent link between duration and contraceptive behaviors-regardless of intimacy, commitment, conflict, or power imbalance-suggests that the continual vigilance required for long-term contraceptive use is difficult during early emerging adulthood.

Intimate relationship dynamics and women's expected control over sex and contraception.

OBJECTIVE: We examined whether women's experiences across and within their intimate relationships affect their expected level of control over sex and contraceptive use. STUDY DESIGN: We used data from 648 women ages 18-20 in the Relationship Dynamics and Social Life (RDSL) study, which interviewed a random, population-based sample in a Michigan county. We used ordered logistic regression with fixed-effects to control for individual- and relationship-level characteristics. RESULTS: We found a u-shaped relationship between intimacy/commitment and expected control, with the lowest expected control in the least intimate/committed and the most intimate/committed relationships, and the highest expected control in the intermediate relationships. Women expected more control in their long-term compared to short-term relationships, and expected control increases over time in a specific relationship. Women also expected less control in their conflictual and/or asymmetric relationships - those with older and/or violent partners, and expected control decreases after experiencing violence or a partner's non-monogamy. CONCLUSIONS: Our results are consistent with cross-sectional research suggesting that women in violent relationships experience more reproductive coercion than women in non-violent relationships, but we also found that other aspects of intimate relationships are important determinants of expected control over sex and contraception. IMPLICATIONS: Intervention strategies should consider a wider range of intimate relationship characteristics - beyond violence - to improve women's control of their reproductive behaviors.

Intimate Relationship Dynamics and Changing Desire for Pregnancy Among Young Women.

CONTEXT: Although substantial research has focused on unintended pregnancy among young women, less is known about the circumstances under which pregnancy is desired. Whether a young woman's pregnancy desire changes across her different relationships, or over time within a relationship, has not been directly assessed. METHODS: Data on intimate relationships and pregnancy desire were assessed weekly for 895 women aged 18-22 who participated in the Relationship Dynamics and Social Life study in a county in Michigan (2008-2012). Within-between logistic regression models were used to examine within-cluster and between-cluster differences-comparisons of a woman's pregnancy desire within a relationship over time as well as across a woman's different relationships. RESULTS: Young women were more likely to desire pregnancy if they were in any relationship more intimate and committed than a casual relationship (odds ratios, 1.6-9.2); the odds of desiring pregnancy were also higher in long-term relationships rather than in short-term ones (2.1). In general, pregnancy desire increased over time as a relationship endured and became more serious. The odds of desiring pregnancy were lower among women with less educated, rather than equally educated, partners (0.7), while the odds were higher in nonmonogamous or violent relationships than in monogamous or nonviolent relationships (1.6 and 1.9, respectively). CONCLUSIONS: Young women's pregnancy desire changes depending on their intimate relationship context, across the range of relationships they experience during the transition to adulthood.

Contraceptive Desert? Black-White Differences in Characteristics of Nearby Pharmacies.

OBJECTIVES: Race differences in contraceptive use and in geographic access to pharmacies are well established. We explore race differences in characteristics of nearby pharmacies that are likely to facilitate (or not) contraceptive purchase. STUDY DESIGN: We conducted analyses with two geocode-linked datasets: (1) the Relationship Dynamics and Social Life (RDSL) project, a study of a random sample of 1003 women ages 18-19 living in a county in Michigan in 2008-09; and (2) the Community Pharmacy Survey, which collected data on 82 pharmacies in the county in which the RDSL study was conducted. RESULTS: Although young African-American women tend to live closer to pharmacies than their white counterparts (1.2 miles to the nearest pharmacy for African Americans vs. 2.1 miles for whites), those pharmacies tend to be independent pharmacies (59 vs. 16%) that are open fewer hours per week (64.6 vs. 77.8) and have fewer female pharmacists (17 vs. 50%), fewer patient brochures on contraception (2 vs. 5%), more difficult access to condoms (49% vs. 85% on the shelf instead of behind glass, behind the counter, or not available), and fewer self-check-out options (3 vs. 9%). More African-American than white women live near African-American pharmacists (8 vs. 3%). These race differences are regardless of poverty, measured by the receipt of public assistance. CONCLUSIONS: Relative to white women, African-American women may face a "contraception desert," wherein they live nearer to pharmacies, but those pharmacies have characteristics that may impede the purchase of contraception.

Sexual Concurrency and Contraceptive Use Among Young Adult Women.

Leveraging 2.5 years of weekly data from the Relationship Dynamics and Social Life Study, we investigate the relationship between young women's sexual concurrency and their contraceptive behavior. Specifically, we (1) examine whether young women changed their contraceptive use when switching from one to multiple concurrent sexual partners in the same week; (2) explore the uniformity of contraceptive responses to concurrency across relationship context; and (3) compare the contraceptive behaviors of never-concurrent women with those of ever-concurrent women in weeks when they were not concurrent. Nearly one in five sexually active young women had sex with two or more people in the same week. When they were concurrent, these women's odds of using any contraception increased threefold, and their odds of using condoms increased fourfold. This pattern of contraceptive adjustments was the same across relationship characteristics, such as duration and exclusivity. Yet when they were not concurrent, ever-concurrent women were less likely to use any contraception and used condoms less consistently than women who were never concurrent. We discuss these findings in the context of ongoing debates about the role of sexual concurrency in STI transmission dynamics.

Dimensions of Reproductive Attitudes and Knowledge Related to Unintended Childbearing Among U.S. Adolescents and Young Adults.

Measures of attitudes and knowledge predict reproductive behavior, such as unintended fertility among adolescents and young adults. However, there is little consensus as to the underlying dimensions these measures represent, how to compare findings across surveys using different measures, or how to interpret the concepts captured by existing measures. To guide future research on reproductive behavior, we propose an organizing framework for existing measures. We suggest that two overarching multidimensional concepts-reproductive attitudes and reproductive knowledge-can be applied to understand existing research using various measures. We adapt psychometric analytic techniques to analyze two data sets: the National Longitudinal Survey of Adolescent to Adult Health (Add Health) and the Relationship Dynamics and Social Life study (RDSL). Although the specific survey measures and sample composition of the two data sets are different, the dimensionality of the concepts and the content of the items used to measure their latent factors are remarkably consistent across the two data sets, and the factors are predictive of subsequent contraceptive behavior. However, some survey items do not seem strongly related to any dimension of either construct, and some dimensions of the two concepts appear to be poorly measured with existing survey questions. Nonetheless, we argue that the concepts of reproductive attitudes and reproductive knowledge are useful for categorizing and analyzing social psychological measures related to unintended fertility. The results can be used to guide secondary data analyses to predict reproductive behavior, compare results across data sets, and structure future data collection efforts.

No one to turn to: low social support and the incidence of undesired pregnancy in the United States.

OBJECTIVE: Young women may experience social barriers to achieving their reproductive goals. This analysis explored whether low social support may contribute to the high incidence of undesired pregnancy in young women in the United States. STUDY DESIGN: Using 6 months of data from a prospective cohort of 970 women ages 18-22 years in the United States, we described contraceptive use and applied multivariable logistic regression and standardization to estimate adjusted odds and absolute risk of undesired pregnancy among women reporting low social support versus higher social support. We investigated several measures of contraceptive use as possible explanations for this pathway. RESULTS: Sixty-five pregnancies were reported in the 6 months of the study, of which 30 (46%) were classified as undesired prior to conception. Among young women who reported low social support, 8% reported an undesired pregnancy during the study period as compared to 3% of the young women who reported higher levels of social support. Among non-black women, those who reported low social support had nearly seven times the odds of an undesired pregnancy as compared to women who reported higher social support (aOR: 6.8, 95%CI: 1.7, 27.1). We found no association between social support and undesired pregnancy among young black women. Contraceptive method use differed by social support at baseline, and throughout follow-up. CONCLUSIONS: Low social support - defined as the feeling of not having anyone to turn to - may be a risk factor for persistently high levels of undesired pregnancy among young women in the U.S. This association may be driven by differences in contraceptive use by level of social support. IMPLICATIONS: Interventions to increase young women's perceptions of social support may reduce the risk of undesired pregnancy for some individuals.

Pregnancy scares and change in contraceptive use.

OBJECTIVE: We examined whether the experience of a "pregnancy scare" is related to subsequent changes in contraceptive use that increase the risk of unintended pregnancy. METHODS: We used data from the Relationship Dynamics and Social Life (RDSL) study, which interviewed a random, population-based sample of 1003 young women weekly for 2.5 years. We used multivariate regression models to predict the effect of experiencing a pregnancy scare on change in contraceptive use. RESULTS: We found pregnancy scares are associated with changes in contraceptive use that increase the risk of pregnancy. Experiencing a pregnancy scare is related to discontinued contraceptive use, change from consistent to inconsistent use of contraception, and change from a more effective to a less effective method of contraception. We also found pregnancy scares are associated with continued inconsistent use of contraception. CONCLUSIONS: Our findings suggest that the experience of a pregnancy scare does not serve as a "wake-up call" to start using contraception, to start using it consistently, or to switch to a more effective method to reduce the risk of unintended pregnancy. Instead, contraceptive use after a pregnancy scare typically remains the same or worsens. IMPLICATIONS: Clinicians should be aware that young women who have experienced pregnancy scares may be at increased risk of unintended pregnancy, relative to young women who did not experience a pregnancy scare.

Physical Intimate Partner Violence and Contraceptive Behaviors Among Young Women.

BACKGROUND: Understanding the link between physical intimate partner violence (IPV) and contraception is key to preventing unintended pregnancy and sexually transmitted infections. MATERIALS AND METHODS: Data from the Relationship Dynamics and Social Life study, a longitudinal study of a racially and socioeconomically diverse population-representative random sample of 18- to 19-year-old women residing in a Michigan county in 2008-2009 and followed weekly through 2011-2012, were used. Logistic regression models of contraceptive behaviors on temporally specific measures of physical violence victimization: recent, history in the current relationship, and history in prior relationships were conducted among 711 women. RESULTS: Women who experienced physical IPV in their current relationship had lower odds of using contraception (odds ratio [OR], 0.47; 95% confidence interval [CI], 0.28, 0.76 for recent; OR, 0.53; 95% CI, 0.33, 0.83 for past). Condom use was lower among women who experienced past physical IPV in their current relationship (OR, 0.44; 95% CI, 0.26, 0.73), while withdrawal use was higher (OR, 1.99; 95% CI, 1.24, 3.19). Women who experienced physical IPV used condoms less consistently (OR, 0.34; 95% CI, 0.13, 0.85 for recent; OR, 0.27; 95% CI, 0.14, 0.52 for prior relationships). CONCLUSIONS: Physical IPV victimization is a dynamic and strong predictor of contraceptive use, method type, and consistency of condom use.

MEDIATION MODELS OF PREGNANCY DESIRES AND UNPLANNED PREGNANCY IN YOUNG, UNMARRIED WOMEN.

This paper examines the proposition that sexual and contraceptive behaviours mediate the relationship between the pregnancy desires of young, unmarried women and their having an unplanned pregnancy. The sample consisted of 854 18- to 19-year-old women living in Michigan, USA. First, the positive and negative pregnancy desires of these women were measured, as were the women's perceptions of the positive and negative desires of their sexual partners. Then the extent to which these four types of desires, as well as several types of interactions between them, prospectively predicted the occurrence of subsequent pregnancies were tested with logistic regression analyses, initially alone and then after the addition of several types of sexual and contraceptive mediator variables. The results demonstrated that four of the ten significant motivational predictors became non-significant following the introduction of the contraceptive mediator variables and that the predictive strength of the other six significant motivational predictors was substantially reduced by their introduction. A number of factors that may account for only a partial mediational effect in some models are discussed.

The Dynamics of Intimate Partner Violence and the Risk of Pregnancy during the Transition to Adulthood.

Using a reproductive coercion framework, we investigate the role of intimate partner violence (IPV) in pregnancy during the transition to adulthood. We use two types of data from a population-based sample of 867 young women in a Michigan county: a 60-minute survey interview with 2.5 years of weekly follow-up surveys, and semi-structured interviews with a subsample of 40 pregnant women. The semi-structured interviews illustrate the violence women experienced. Discrete-time logit hazard models demonstrate that threats and physical assault are associated with higher pregnancy rates during ages 18 to 22. However, this holds only when the violence is recent; violence occurring more than a month earlier is not associated with higher pregnancy rates. These associations are independent of violent experiences with prior partners, which are also associated with higher pregnancy rates. Fixed-effects models show that during violent weeks, women perceive more pregnancy desire from their partners, have more sex, and use less contraception than during nonviolent weeks. Finally, mediation analyses and the semi-structured interviews are consistent with reproductive coercion: violent young men are more likely to want their girlfriends pregnant, and they use threats and physical assault to implement their preferences via sex and contraceptive non-use, which in turn increase pregnancy rates.