Rates of positivity for six drug classes.

<p><b>^{^}</b>Pearson Chi-square test performed; <b>^&</b>Fisher’s Exact test performed; *Methadone positive n=98, Methadone negative n=92; <b>^#</b>Methadone positive n=28, Methadone negative n=62; <b>⁺</b>Methadone positive n=68, Methadone negative n=60</p

Rates of positivity for individual compounds.

<p><b>^{^}</b>Pearson Chi-square test performed; <b>^&</b>Fisher’s Exact test performed; <b>*</b>Methadone positive n=113, Methadone negative n=92; <b>^#</b>Methadone positive n=112, Methadone negative n=92; <b>^$</b>Methadone positive n=111, Methadone negative n=92; <b>^%</b>Methadone positive n=22, Methadone negative n=66; <b>⁼</b>Methadone positive n=162, Methadone negative n=108; <b>⁺</b>Methadone positive n=162, Methadone negative n=106; <b>^<i>a</i></b>Methadone positive n=162, Methadone negative n=108</p

Recruitment rate over time.

<p>Recruitment through traditional healthcare-based advertising constituted the first phase of recruitment from April 2007–November 2011. Starting December 2011–May 2012, new social media based recruitment strategies were applied along with continued use of traditional healthcare-based recruitment. Recruitment rates in the two phases were compared using the Mann Whitney U test.</p

Summary of Multiple Regression Analysis.

<p>Summary of Multiple Regression Analysis.</p

Interrupted Time Series: recruitment after the intervention of social media.

<p>Monthly recruitment <i>before</i> and <i>after</i> the intervention of social media, as observed and fitted with a logarithmic time-series model, within a 95% confidence interval. A forecast plot is also applied to predict the upward trend in recruitment observed after the intervention with social media.</p

What constitutes Social Media?

<p>The various online social media and networking platforms used for the recruitment of pregnant and planning women in the study.</p

Study design.

<p>An outline of the study design.</p

Characteristics of women recruited by traditional methods vs. social media.

<p>Characteristics of women recruited by traditional methods vs. social media.</p

Success of recruitment strategies over time.

<p>Recruitment through traditional healthcare-based advertising constituted the first phase of recruitment from April 2007–November 2011. Starting December 2011–May 2012, new social media based recruitment strategies were applied along with continued use of traditional healthcare-based recruitment. Yearly recruitment in the two phases was compared using the Mann Whitney U test.</p

Breakdown of Recruitment.

<p>Breakdown of Recruitment.</p