A Web-Based Event History Calendar Approach for Measuring Contraceptive Use Behavior.

Event history calendars (EHCs) are frequently used in social measurement to capture important information about the time ordering of events in people's lives, and enable inference about the relationships of the events with other outcomes of interest. To date, EHCs have primarily been designed for face-to-face or telephone survey interviewing, and few calendar tools have been developed for more private, self-administered modes of data collection. Web surveys offer benefits in terms of both self-administration, which can reduce social desirability bias, and timeliness. We developed and tested a web application enabling the calendar-based measurement of contraceptive method use histories. These measures provide valuable information for researchers studying family planning and fertility behaviors. This study describes the development of the web application, and presents a comparison of data collected from online panels using the application with data from a benchmark face-to-face survey collecting similar measures (the National Survey of Family Growth).

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.

Using life history calendars to improve measurement of lifetime experience with mental disorders.

BACKGROUND: Retrospective reports of lifetime experience with mental disorders greatly underestimate the actual experiences of disorder because recall error biases reporting of earlier life symptoms downward. This fundamental obstacle to accurate reporting has many adverse consequences for the study and treatment of mental disorders. Better tools for accurate retrospective reporting of mental disorder symptoms have the potential for broad scientific benefits. METHODS: We designed a life history calendar (LHC) to support this task, and randomized more than 1000 individuals to each arm of a retrospective diagnostic interview with and without the LHC. We also conducted a careful validation with the Structured Clinical Interview for the Diagnostic and Statistical Manual of Mental Disorders-Fourth Edition. RESULTS: Results demonstrate that-just as with frequent measurement longitudinal studies-use of an LHC in retrospective measurement can more than double reports of lifetime experience of some mental disorders. CONCLUSIONS: The LHC significantly improves retrospective reporting of mental disorders. This tool is practical for application in both large cross-sectional surveys of the general population and clinical intake of new patients.

The utility of a follow-up interview for respondents to a longitudinal survey with frequent measurement.

Social processes that change quickly are difficult to study, because they require frequent survey measurement. Weekly, daily, or even hourly measurement may be needed depending on the topic. With more frequent measurement comes the prospect of more complex patterns of missing data. The mechanisms creating the missing data may be varied, ranging from technical issues such as lack of an Internet connection to refusal to complete a requested survey. We examine one approach to mitigating the damage of these missing data - a follow-up or closeout interview that is completed after the frequent measurement. The Relationship Dynamics and Social Life (RDSL) study used this approach. The study asked women weekly about their attitudes and behaviors related to sexual relationships and pregnancy. The surveys were carried out for 130 weeks and concluded with a closeout interview. We explore the patterns of missing data in the RDSL study and then examine associations between the data collected in the closeout survey and key variables collected in the weekly survey. We then assess the extent to which data from the closeout survey are useful in repairing the damage caused by missing data.

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.

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.

Participation in an Intensive Longitudinal Study with Weekly Web Surveys Over 2.5 Years.

BACKGROUND: Technological advances have made it easier for researchers to collect more frequent longitudinal data from survey respondents via personal computers, smartphones, and other mobile devices. Although technology has led to an increase in data-intensive longitudinal studies, little is known about attrition from such studies or the differences between respondents who complete frequently administered surveys in a timely manner, and respondents who do not. OBJECTIVE: We examined respondent characteristics and behaviors associated with continued and on-time participation in a population-based intensive longitudinal study, using weekly web-based survey interviews over an extended period. METHODS: We analyzed data from the Relationship Dynamics and Social Life study, an intensive longitudinal study that collected weekly web-based survey interviews for 2.5 years from 1003 18- and 19-year-olds to investigate factors shaping the dynamics of their sexual behavior, contraceptive use, and pregnancies. RESULTS: Ordinary least squares and logistic regression analyses showed background respondent characteristics measured at baseline were associated with the number of days respondents remained enrolled in the study, the number of interviews they completed, and the odds that they were late completing interviews. In addition, we found that changes in pregnancy-related behaviors reported in the weekly interviews were associated with late completion of interviews. Specifically, after controlling for sociodemographic, personality, contact information, and prior experience variables, we found that weekly reports such as starting to have sex (odds ratio [OR] 1.17, 95% CI 1.03-1.32, P=.01), getting a new partner (OR 1.76, 95% CI 1.53-2.03, P<.001), stopping the use of contraception (OR 1.28, 95% CI 1.10-1.49, P=.001), and having a new pregnancy (OR 5.57, 95% CI 4.26-7.29, P<.001) were significantly associated with late survey completion. However, young women who reported changes in pregnancy-related behaviors also had lower levels of study attrition, and completed more interviews overall, than did their counterparts. CONCLUSIONS: We found that measures of participation in a longitudinal study with weekly web surveys varied not only by respondent characteristics, but also by behaviors measured across the surveys. Our analyses suggest that respondents who experience the behaviors measured by the study may maintain higher participation levels than respondents who do not experience those behaviors.

Effects of intensive longitudinal data collection on pregnancy and contraceptive use.

We use an experiment based on the Relationship Dynamics and Social Life (RDSL) study of sexual behavior, pregnancy, and contraceptive use to investigate whether participation in weekly self-reports over one year result in differential effects on related behaviors and attitudes, compared to participation in a one-time follow-up interview requiring retrospective self-reporting for the prior year. We randomly assigned 200 subjects to either a control group or a journal group. All subjects were interviewed at the beginning of the study (baseline interview) and 12 months later (closeout interview). Subjects in the journal group also completed a five-minute web- or phone-based survey every week during the 12-month study period. We found no statistically significant difference in pregnancy rates across the two groups at closeout. Contrary to our expectation, the control group experienced a slightly larger increase in having ever used a contraceptive method, although this was mainly due to increases in the least effective methods, such as condoms and withdrawal. Respondents in the weekly interview group became slightly more positive toward childbearing in terms of one specific attitude measure, but not for the vast majority of measures. We conclude that intensive longitudinal data collection does not appear to have a large or consistent impact on respondents' pregnancy, contraceptive use, or related attitudes, relative to the more standard longitudinal approach.

Black-White Differences in Attitudes Related to Pregnancy Among Young Women.

In this article, we use newly available data from the Relationship Dynamics and Social Life (RDSL) study to compare a wide range of attitudes related to pregnancy for 961 black and white young women. We also investigate the extent to which race differences are mediated by, or net of, family background, childhood socioeconomic status (SES), adolescent experiences related to pregnancy, and current SES. Compared with white women, black women generally have less positive attitudes toward young nonmarital sex, contraception, and childbearing, and have less desire for sex in the upcoming year. This is largely because black women are more religious than white women and partly because they are more socioeconomically disadvantaged in young adulthood. However, in spite of these less positive attitudes, black women are more likely to expect sex without contraception in the next year and to expect more positive consequences if they were to become pregnant, relative to white women. This is largely because, relative to white women, black women had higher rates of sex without contraception in adolescence and partly because they are more likely to have grown up with a single parent. It is unclear whether attitudes toward contraception and pregnancy preceded or are a consequence of adolescent sex without contraception. Some race differences remain unexplained; net of all potential mediators in our models, black women have less desire for sex in the upcoming year, but they are less willing to refuse to have sex with a partner if they think it would make him angry and they expect more positive personal consequences of a pregnancy, relative to white women. In spite of these differences, black women's desires to achieve and to prevent pregnancy are very similar to white women's desires.

Young women's perceptions and experiences with contraception supply in community pharmacies.

BACKGROUND: Unintended pregnancy is a major public health problem in the United States.Correct contraceptive use can reduce the rate of unintended pregnancy. Community pharmacies are well positioned to provide contraceptives and advice about contraception. OBJECTIVES: To determine young women's perceptions and experiences with contraception supply in community pharmacies and to identify whether pharmacy characteristics predicted very positive experiences. DESIGN: This study comprised two cross-sectional surveys including an online women's pharmacy perceptions and experiences (PPE) survey and a faxed/observed survey of community pharmacies. SETTING: One county in Michigan. PARTICIPANTS: Young women and community pharmacies. MAIN OUTCOME MEASURE: The two surveys were merged to explore pharmacy characteristics that may impact women's perceptions and experiences with community pharmacies. Multiple logistic regression analysis was used to explore relationships between pharmacy characteristics and positive outcomes. RESULTS: The response rate for the PPE survey was 54% (n = 343/637). Data from all community pharmacies in the county was retrieved via fax (n = 41/94, 43.6%) or observation (n = 53/94, 56.4%). Women were included in this analysis if they indicated a regular pharmacy (one they go to most often) in the county of interest (n = 210). More than 50% of women (n = 125/210) visited a pharmacy more than once per month. Sixty percent of women were currently using something to prevent pregnancy (n = 124/210, 60.8%). Thirty-five percent of women had a positive experience (n = 73/210, 34.8%). In the multiple logistic regression, women who visited a chain pharmacy had almost 65% lower odds of an overall positive experience with their regular pharmacy compared with women who visited a grocery or mass merchandise pharmacy (odds ratio 0.35 [95% CI 0.16], P = 0.75). CONCLUSION: Young women visit community pharmacies and use contraceptives frequently. Interventions need to be developed and implemented to improve young women's perceptions and experiences with contraception at community pharmacies.

Social discrimination, stress, and risk of unintended pregnancy among young women.

PURPOSE: Prior research linking young women's mental health to family planning outcomes has often failed to consider their social circumstances and the intersecting biosocial mechanisms that shape stress and depression as well as reproductive outcomes during adolescence and young adulthood. We extend our previous work to investigate relationships between social discrimination, stress and depression symptoms, and unintended pregnancy among adolescent and young adult women. METHODS: Data were drawn from 794 women aged 18-20 years in a longitudinal cohort study. Baseline and weekly surveys assessed psychosocial information including discrimination (Everyday Discrimination Scale), stress (Perceived Stress Scale), depression (Center for Epidemiologic Studies-Depression Scale), and reproductive outcomes. Multilevel, mixed-effects logistic regression and discrete-time hazard models estimated associations between discrimination, mental health, and pregnancy. Baron and Kenny's method was used to test mediation effects of stress and depression on discrimination and pregnancy. RESULTS: The mean discrimination score was 19/45 points; 20% reported moderate/high discrimination. Discrimination scores were higher among women with stress and depression symptoms versus those without symptoms (21 vs. 18 points for both, p < .001). Pregnancy rates (14% overall) were higher among women with moderate/high (23%) versus low (11%) discrimination (p < .001). Discrimination was associated with stress (adjusted relative risk ratio, [aRR], 2.2; 95% confidence interval [CI], 1.4-3.4), depression (aRR, 2.4; CI, 1.5-3.7), and subsequent pregnancy (aRR, 1.8; CI, 1.1-3.0). Stress and depression symptoms did not mediate discrimination's effect on pregnancy. CONCLUSIONS: Discrimination was associated with an increased risk of mental health symptoms and unintended pregnancy among these young women. The interactive social and biological influences on reproductive outcomes during adolescence and young adulthood warrant further study.

Maximizing Data Quality using Mode Switching in Mixed-Device Survey Design: Nonresponse Bias and Models of Demographic Behavior.

Conducting survey interviews on the internet has become an attractive method for lowering data collection costs and increasing the frequency of interviewing, especially in longitudinal studies. However, the advantages of the web mode for studies with frequent re-interviews can be offset by the serious disadvantage of low response rates and the potential for nonresponse bias to mislead investigators. Important life events, such as changes in employment status, relationship changes, or moving can cause attrition from longitudinal studies, producing the possibility of attrition bias. The potential extent of such bias in longitudinal web surveys is not well understood. We use data from the Relationship Dynamics and Social Life (RDSL) study to examine the potential for a mixed-device approach with active mode switching to reduce attrition bias. The RDSL design allows panel members to switch modes by integrating telephone interviewing into a longitudinal web survey with the objective of collecting weekly reports. We found that in this design allowing panel members to switch modes kept more participants in the study compared to a web only approach. The characteristics of persons who ever switched modes are different than those who did not - including not only demographic characteristics, but also baseline characteristics related to pregnancy and time-varying characteristics that were collected after the baseline interview. This was true in multivariate models that control for multiple of these dimensions simultaneously. We conclude that mode options and mode switching is important for the success of longitudinal web surveys to maximize participation and minimize attrition.

Stress symptoms and frequency of sexual intercourse among young women.

INTRODUCTION: We have previously documented the relationships between stress and depression symptoms and adolescent women's nonuse and misuse of condoms and other contraceptive methods and on their unintended pregnancy rates. AIM: Here, we examine relationships between mental health symptoms and another understudied adolescent reproductive health behavior-frequency of sexual intercourse. MAIN OUTCOME MEASURE: Our outcome was weekly sexual intercourse activity. METHODS: We used panel data from a longitudinal, population-based cohort study of 992 women ages 18-20. Weekly journals measured sociodemographic, relationship, reproductive, and mental health characteristics, sexual and contraceptive behaviors, and pregnancy history. We examined 27,130 surveys from 952 women during the first study year. Predictors of weekly sexual intercourse were moderate to severe stress (Perceived Stress Scale-4) and depression (Center for Epidemiologic Studies Depression Scale-5) symptoms measured at baseline. Multilevel, mixed-effects logistic regression models estimated the relationships between stress and depression symptoms and the weekly odds of sexual intercourse while adjusting for covariate fixed effects and random woman effects. RESULTS: Nearly a quarter of the sample had moderate to severe stress (23%) and depression (24%) symptoms at baseline. Women reported sexual intercourse in 36% of weeks. Proportions of sexually active weeks were higher among women with stress (43%) and depression (40%) compared with those without symptoms (35% and 35%, respectively; P values<0.001). Controlling for covariates, women with baseline stress symptoms had 1.6 times higher weekly odds of sexual intercourse compared with women without stress (adjusted odds ratio 1.6, confidence interval [1.1, 2.5]; P=0.04). Depression symptoms were not associated with sexual intercourse frequency in adjusted models. CONCLUSIONS: Stress symptoms were positively associated with sexual intercourse frequency among these young women. Research and practice efforts are needed to identify effective sexual health promotion and risk-reduction strategies, including contraceptive education and counseling, in the context of mental health symptoms and unintended pregnancy.

The risk of unintended pregnancy among young women with mental health symptoms.

Depression and stress have been linked with poor contraceptive behavior, but whether existing mental health symptoms influence women's subsequent risk of unintended pregnancy is unclear. We prospectively examined the effect of depression and stress symptoms on young women's pregnancy risk over one year. We used panel data from a longitudinal study of 992 U.S. women ages 18-20 years who reported a strong desire to avoid pregnancy. Weekly journal surveys measured relationship, contraceptive use and pregnancy outcomes. We examined 27,572 journal surveys from 940 women over the first study year. Our outcome was self-reported pregnancy. At baseline, we assessed moderate/severe depression (CESD-5) and stress (PSS-4) symptoms. We estimated the effect of baseline mental health symptoms on pregnancy risk with discrete-time, mixed-effects, proportional hazard models using logistic regression. At baseline, 24% and 23% of women reported moderate/severe depression and stress symptoms, respectively. Ten percent of young women not intending pregnancy became pregnant during the study. Rates of pregnancy were higher among women with baseline depression (14% versus 9%, p = 0.04) and stress (15% versus 9%, p = 0.03) compared to women without symptoms. In multivariable models, the risk of pregnancy was 1.6 times higher among women with stress symptoms compared to those without stress (aRR 1.6, CI 1.1,2.7). Women with co-occurring stress and depression symptoms had over twice the risk of pregnancy (aRR 2.1, CI 1.1,3.8) compared to those without symptoms. Among women without a prior pregnancy, having co-occurring stress and depression symptoms was the strongest predictor of subsequent pregnancy (aRR 2.3, CI 1.2,4.3), while stress alone was the strongest predictor among women with a prior pregnancy (aRR 3.0, CI 1.1,8.8). Depression symptoms were not independently associated with young women's pregnancy risk. In conclusion, stress, and especially co-occurring stress and depression symptoms, consistently and adversely influenced these young women's risk of unintended pregnancy over one year.

Pregnancy scares and subsequent unintended pregnancy.

BACKGROUND: A substantial number of young women experience pregnancy scares - thinking they might be pregnant, and later discovering that they are not. Although pregnancy scares are distressing events, little is known about who experiences them and whether they are important to our understanding of unintended pregnancy. OBJECTIVE: We describe the young women who experience pregnancy scares, and examine the link between pregnancy scares and subsequent unintended pregnancy. METHODS: We used data from the Relationship Dynamics and Social Life Study. T-tests and regression analyses were conducted using baseline and weekly data to estimate relationships between respondent characteristics and subsequent pregnancy scares. Event history methods were used to assess pregnancy scares as a predictor of unintended pregnancy. RESULTS: Nine percent of the young women experienced a pregnancy scare during the study. African-American race, lack of two-parent family structure, lower GPA, cohabitation, and sex without birth control prior to the study are associated with experiencing a pregnancy scare and with experiencing a greater number of pregnancy scares. Further, experiencing a pregnancy scare is strongly associated with subsequent unintended pregnancy, independent of background factors. Forty percent of the women who experienced a pregnancy scare subsequently had an unintended pregnancy during the study period, relative to only 11% of those who did not experience a pregnancy scare. CONCLUSIONS: Young women from less advantaged backgrounds are more likely to experience a pregnancy scare, and pregnancy scares are often followed by an unintended pregnancy.

New strategies for biosample collection in population-based social research.

This paper aims to increase understanding of the methodological issues involved in adding biomeasures to social research by investigating the potential of an event-triggered, self-collection technique for monitoring biological response to social events. We use data from the Relationship Dynamics and Social Life (RDSL) study, which collected saliva samples triggered by a life event important to the aims of the study - the end of a romantic relationship. Our investigation found little evidence that those who complied in the biosample collection were different from those who did not comply in terms of key study measures and sociodemographic characteristics. We also found no evidence that the biosample collection had adverse consequences for subsequent panel participation. We did find that prior cooperation in the study was an important predictor of biosample cooperation, which is important information in developing biosample collection strategies. As demand for biological samples directly linked to social data continues to grow, effective low-cost collection methods will become increasingly valuable. The evidence here indicates that self-collected biosamples may offer tremendous potential to meet this demand.