Bio


Graduated MIT with a degree in Biology, UCSF MD, Children's Hospital Oakland for pediatrics residency, UCSF for Adolescent Medicine Fellowship. UC Berkeley for MPH in Child and Maternal Health specializing in obesity.

Currently, I work at the Weight clinic, where I help patients and families improve their food choices and check for co-morbidities of obesity such as hyperinsulinemia, obstructive sleep apnea, vitamin D deficiency, and prepare for bariatric surgery, if applicable. I enjoy seeing adolescents for general well child checkups but I also enjoy doing "outpatient gynecology" for Teens and young adults. I particularly like discussing birth control options, sexually transmitted infections, that menstruation is optional, and treating acne and menstrual cramps.

Also, I am the CEO & Co-Founder of www.PandiaHealth.com, a birth control delivery company that also provides a doctor's consult if needed.

Clinical Focus


  • Adolescent Medicine
  • Reproductive Health
  • Contraception
  • Menstrual regulation
  • Acne
  • Obesity

Academic Appointments


Administrative Appointments


  • Clinical Associate Professor, Stanford Medical School (2016 - Present)
  • Clinical Assistant Professor, LPCH/Stanford Medical School (2011 - 2016)
  • Clinical Instructor, LPCH (2003 - 2011)

Honors & Awards


  • Outstanding Interdepartmental Faculty Professor, Chosen by the Resident Staff of the Department of Obstetrics and Gynecology (2007-08)
  • Pediatric Clerkship Faculty Honor Roll, Dept of Pediatrics, Stanford Medical School (2007, 2008, 2010, 2012, 2014, 2015)
  • Faculty Teaching Award, Stanford Medical School, LPCH. (2006)
  • MCHB Postdoctoral Training Fellowship in Adolescent Health, Division of Adolescent Medicine, Department of Pediatrics, University of California, San Francisco (2000-2003)
  • Special graduation award for Student Advocacy, UCSF Class of 1997 (1997)

Boards, Advisory Committees, Professional Organizations


  • Executive Committee, Section On Adolescent Health, American Academy of Pediatrics (2015 - Present)
  • Member, Association of Reproductive Health Professionals (2012 - 2018)
  • President, Society for Adolescent Health and Medicine, Northern CA Chapter (2011 - 2013)
  • Vice President/President Elect, Society for Adolescent Health and Medicine, Northern CA Chapter (2009 - 2011)
  • Member, Society for Adolescent Health and Medicine (2000 - Present)
  • Member, American Academy of Pediatrics (1998 - Present)

Professional Education


  • Board Certification: American Board of Pediatrics, Adolescent Medicine (2003)
  • Residency: UCSF Pediatric Fellowships (2000) CA
  • Internship: UCSF Pediatric Fellowships (1998) CA
  • Medical Education: University of California at San Francisco School of Medicine (1997) CA
  • MPH, UC Berkeley, Maternal Child Health (2004)
  • Fellowship: UCSF Adolescent Medicine (2003) CA
  • Residency, Children's Hospital Oakland, Pediatrics (2000)
  • MD, UCSF (1997)
  • BS, MIT, Biology (1993)

Community and International Work


  • Member of Exec Committee, Section On Adolescent Health

    Topic

    Adolescent Health

    Partnering Organization(s)

    American Academy of Pediatrics

    Populations Served

    children and young adults

    Location

    US

    Ongoing Project

    Yes

    Opportunities for Student Involvement

    No

  • President, N. CA SAHM

    Topic

    Adolescent Health

    Partnering Organization(s)

    N. CA Society for Adolescent Health and Medicine

    Populations Served

    health professionals, adolescents

    Location

    Bay Area

    Ongoing Project

    No

    Opportunities for Student Involvement

    No

  • SheHeroes.org, co-founder, Board president

    Topic

    Showing 3rd-6th graders that women can be whatever they work hard towards

    Partnering Organization(s)

    http://sheheroes.org/

    Location

    US

    Ongoing Project

    Yes

    Opportunities for Student Involvement

    Yes

  • Silver Ribbon Campaign to Trust Women

    Topic

    Reproductive rights, abortion, women's equality

    Partnering Organization(s)

    http://oursilverribbon.org/

    Location

    US

    Ongoing Project

    Yes

    Opportunities for Student Involvement

    Yes

  • N. CA AAP Pediatric Obesity Interest Group

    Topic

    Pediatric Obesity

    Partnering Organization(s)

    AAP

    Populations Served

    community, MDs, patients

    Location

    Bay Area

    Ongoing Project

    Yes

    Opportunities for Student Involvement

    Yes

  • Reproductive Rights

    Topic

    Access to contraception and abortion

    Partnering Organization(s)

    Physicians for Reproductive Choice and Health, Center for Reproductive Rights

    Populations Served

    all

    Location

    US

    Ongoing Project

    Yes

    Opportunities for Student Involvement

    Yes

  • Vice President, N. CA SAHM

    Topic

    Adolescent medicine

    Partnering Organization(s)

    N. CA Society for Adolescent Health and Medicine

    Location

    Bay Area

    Ongoing Project

    No

    Opportunities for Student Involvement

    No

Current Research and Scholarly Interests


Emergency contraception access, availability, knowledge.

Pediatric obesity and its treament with videogames and pedometers.

Adolescent use and access to contraception.

Using computers to educate patients during waiting time.

Determinants of Tampon use/initiation.

Health needs of adolescents in local high schools. Obesity, exercise, mental health, reproductive health.

Attitudes towards a reproductive health clinic - parents perspective, adolescents.

2024-25 Courses


Graduate and Fellowship Programs


  • Adolescent Medicine (Fellowship Program)

All Publications


  • The Contraceptive Ring, Patch, and Pills: An Update AM:STARs Adolescent Medicine State of the Art Reviews Yen, S., Cahill, E. P. 2019: 60-81
  • Improving adolescent knowledge of emergency contraception: challenges and solutions Open Access Journal of Contraception Seetharaman , S., Sophia, Y., Seth, A. D. 2016: 161-173
  • Improving adolescent knowledge of emergency contraception: challenges and solutions OPEN ACCESS JOURNAL OF CONTRACEPTION Seetharaman, S., Yen, S., Ammerman, S. D. 2016; 7: 161–73

    Abstract

    Globally, unintended adolescent pregnancies pose a significant burden. One of the most important tools that can help prevent unintended pregnancy is the timely use of emergency contraception (EC), which in turn will decrease the need for abortions and complications related to adolescent pregnancies. Indications for the use of EC include unprotected sexual intercourse, contraceptive failure, or sexual assault. Use of EC is recommended within 120 hours, though is most effective if used as soon as possible after unprotected sex. To use EC, adolescents need to be equipped with knowledge about the various EC methods, and how and where EC can be accessed. Great variability in the knowledge and use of EC around the world exists, which is a major barrier to its use. The aims of this paper were to 1) provide a brief overview of EC, 2) discuss key social determinants affecting knowledge and use of EC, and 3) explore best practices for overcoming the barriers of lack of knowledge, use, and access of EC.

    View details for PubMedID 29386948

  • Emergency Contraception Pill Awareness and Knowledge in Uninsured Adolescents: High Rates of Misconceptions Concerning Indications for Use, Side Effects, and Access. Journal of pediatric and adolescent gynecology Yen, S., Parmar, D. D., Lin, E. L., Ammerman, S. 2015; 28 (5): 337-342

    Abstract

    To determine the awareness of, access to, and knowledge of the proper use of emergency contraception pills (ECPs) among uninsured adolescents.Anonymous surveys were used to assess awareness of, knowledge of, and access to ECPs.From 2010 to 2012 at mobile primary care clinic in the San Francisco Bay Area.Patients were uninsured adolescents aged 13 to 25; 40% of the participants were currently or had been homeless in the past year. Ethnicity was 50% Asian, 22% Hispanic, 17% Pacific Islanders, 5.5% white, and 5.5% other/mixed ethnicity.Post survey completion, patients received one-on-one 15-minute dedicated ECP education.Awareness of, knowledge of, and access to ECPs.Of the study population of 439, 30% of the participants were 13-16 years old and 70% were 17-25 years old (mean age 17.8 years); 66% were women. Young women (86%) reported higher rates of "hearing about emergency contraception" than did young men (70%) (P < .0001). Many incorrectly identified or were uncertain if ECPs were an abortion pill (40%) or could be used as regular birth control (40%) or to prevent sexually transmitted infections (19%). Only 40% of women and 43% of men aged 17 and older correctly answered that they could obtain EC over the counter; 72% did not know that males could receive EC for use by their partner; 12% incorrectly selected that infertility was a side effect; 44% were under the false impression that EC had to be taken within 1 day of unprotected sex.Uninsured adolescents have high rates of ECP awareness but low ECP knowledge. These adolescents need more ECP education to alleviate misconceptions and increase practical knowledge, specifically, education about male access, side effects, over-the-counter availability for young men and women, and the 120-hour window of use.

    View details for DOI 10.1016/j.jpag.2014.09.018

    View details for PubMedID 26148784

  • Development of an Accelerometer-Linked Online Intervention System to Promote Physical Activity in Adolescents PLOS ONE Guthrie, N., Bradlyn, A., Thompson, S. K., Yen, S., Haritatos, J., Dillon, F., Cole, S. W. 2015; 10 (5)

    Abstract

    Most adolescents do not achieve the recommended levels of moderate-to-vigorous physical activity (MVPA), placing them at increased risk for a diverse array of chronic diseases in adulthood. There is a great need for scalable and effective interventions that can increase MVPA in adolescents. Here we report the results of a measurement validation study and a preliminary proof-of-concept experiment testing the impact of Zamzee, an accelerometer-linked online intervention system that combines proximal performance feedback and incentive motivation features to promote MVPA. In a calibration study that parametrically varied levels of physical activity in 31 12-14 year-old children, the Zamzee activity meter was shown to provide a valid measure of MVPA (sensitivity in detecting MVPA = 85.9%, specificity = 97.5%, and r = .94 correspondence with the benchmark RT3 accelerometer system; all p < .0001). In a subsequent randomized controlled multi-site experiment involving 182 middle school-aged children assessed for MVPA over 6 wks, intent-to-treat analyses found that those who received access to the Zamzee intervention had average MVPA levels 54% greater than those of a passive control group (p < 0.0001) and 68% greater than those of an active control group that received access to a commercially available active videogame (p < .0001). Zamzee's effects on MVPA did not diminish significantly over the course of the 6-wk study period, and were statistically significant in both females and males, and in normal- vs. high-BMI subgroups. These results provide promising initial indications that combining the Zamzee activity meter with online proximal performance feedback and incentive motivation features can positively impact MVPA levels in adolescents.

    View details for DOI 10.1371/journal.pone.0128639

    View details for Web of Science ID 000355183900246

    View details for PubMedID 26010359

    View details for PubMedCentralID PMC4444279

  • Pilot Study of Reproductive Health Counseling in a Pediatric Rheumatology Clinic ARTHRITIS CARE & RESEARCH Ronis, T., Frankovich, J., Yen, S., Sandborg, C., Chira, P. 2014; 66 (4): 631-635

    Abstract

    Objective: To assess perception and behavior after reproductive health counseling among adolescent patients in a tertiary care-based pediatric rheumatology clinic. Methods: Adolescent females seen at Stanford pediatric rheumatology clinic were prospectively enrolled during routine visits. At study start, standard clinic procedures for the following were reviewed with providers: 1) HEADSS (home, education, activities, drugs, sexual activity, and suicide/depression) assessment; 2) reproductive health counseling; and 3) medical record documentation. Patients were enrolled if providers indicated that they performed HEADSS assessment and reproductive health counseling. At enrollment, patients completed a survey to assess perceptions of reproductive health counseling. Chart review confirmed documented discussions. Follow-up survey 3-5 months after enrollment tracked reproductive health information seeking behavior. Results: Ninety females (ages 17 ± 2 years old) participated. Almost all patients (99%) agreed that reproductive health was discussed. Seventy-one percent reported that pregnancy risks were discussed, 42% had recent concerns about reproductive health, and 33% reported their provider recommended that they seek further reproductive health care. Eighty-four patients completed follow-up phone surveys, with 25% reporting seeking further information on reproductive health concerns but merely 9.5% actually sought further care. Only 18% reported having ever asked their rheumatology provider for guidance regarding reproductive health care concerns. Conclusion: Routine reproductive health discussion and counseling are necessary in a rheumatology clinic; as in our experience, a substantial number of adolescents have concerns and actively seek reproductive health information. Despite these discussions, teens rarely pursued further reproductive health care. Further work to bridge this gap is needed.

    View details for DOI 10.1002/acr.22159

    View details for Web of Science ID 000333380400017

    View details for PubMedCentralID PMC4087090

  • Contraception for Adolescents PEDIATRIC ANNALS Yen, S., Martin, S. 2013; 42 (2): 21-25

    Abstract

    CME EDUCATIONAL OBJECTIVES: 1.Identify and explain the four currently available methods of emergency contraception.2.Discuss the risk and benefits of intrauterine devices as a first-line option for contraception in adolescents.3.Review strategies for explaining the most common contraceptive methods to an adolescent. The US has the highest pregnancy rate of any industrialized nation, approximately twice that of Canada, four times that of France, and eight times that of Japan or Italy.1 In recent years, the rate has declined, partially due to delayed coitarche (age of onset of vaginal sexual intercourse) but mainly due to greater use of contraception.2 Per the 2011 Youth Risk Behavior Survey (a national survey of about 15,000 youth in schools), 33% of high school freshmen, 44% of sophomores, 53% of juniors, and 63% of seniors have had vaginal sexual intercourse. To prevent unplanned and unwanted teenage pregnancies, which have negative consequences on a teenager's health and future, pediatricians must be able to provide birth control or at least know where to refer their patients in need.

    View details for DOI 10.3928/00904481-20130128-08

    View details for Web of Science ID 000316248600001

    View details for PubMedID 23379400

  • Direct pharmacy access to hormonal contraception: California physician and advanced practice clinician views CONTRACEPTION Rafie, S., Haycock, M., Rafie, S., Yen, S., Harper, C. C. 2012; 86 (6): 687-693

    Abstract

    The United States has high rates of unintended pregnancy, and many women report difficulties in obtaining contraception. Pharmacy access would expand access to hormonal contraception.A qualitative study using a structured interview guide was conducted with 20 reproductive health practitioners including physicians and advanced practice clinicians in California in 2008-2009.Most respondents considered the current prescription-only model of access to hormonal contraception to be too restrictive. Some reported a preference for a pharmacy access model where women could obtain contraceptives directly from a pharmacist, bypassing the clinic visit. Many providers believed that method continuation and compliance would improve with pharmacy access to contraception. The most common concern reported was pharmacist refusal to provide services.Overall, providers viewed increased access to hormonal contraception as an important public health service and supported pharmacy access. They thought that pharmacy access can be accomplished through pharmacist education and training. Additional research is needed to test the hypothesis generated by this qualitative study that physicians and advanced practice clinicians would welcome an enhanced role of pharmacists in the provision of hormonal contraception.

    View details for DOI 10.1016/j.contraception.2012.05.010

    View details for Web of Science ID 000311195700013

    View details for PubMedID 22717185

  • Pediatric Residents' Knowledge, Use, and Comfort With Expedited Partner Therapy for STIs PEDIATRICS Hsii, A., Hillard, P., Yen, S., Golden, N. H. 2012; 130 (4): 705-711

    Abstract

    We examined California pediatric residents' knowledge, practices, and comfort of providing expedited partner therapy (EPT) for sexually transmitted infections, by postgraduate year of training and presence of an adolescent medicine fellowship. We hypothesized that few residents are aware of EPT, and fewer are comfortable providing it; knowledge, practices, and comfort increase during residency; and presence of an adolescent medicine fellowship increases knowledge, practices, and comfort.Online anonymous questionnaires were completed by pediatric residents from 14 California programs.Two hundred eighty-nine pediatric residents (41% response; mean age, 29.4 ± 2.7 years; 78% female) responded. Twenty-two percent reported being moderately or very familiar with EPT. Most correctly identified several EPT methods. Incorrectly identified as EPT included patient (55%), health department (42%), and provider (37%) referrals. Only 8% were aware of California's legal status regarding EPT. Sixty-nine percent knew that California law allows EPT for chlamydia and gonorrhea, but 38% incorrectly stated that EPT can be used to treat trichomoniasis. Fifty-two percent reported ever providing EPT, but 30% of them were uncomfortable doing so. Postgraduate year 1 residents were significantly more likely to report lack of experience as a barrier to prescribing EPT. Residents in programs with the presence of an adolescent medicine fellowship had significantly higher global knowledge scores and were more likely to practice EPT with fewer concerns.California pediatric residents have knowledge gaps and discomfort providing EPT, and the presence of adolescent medicine fellowship is associated with increased EPT knowledge, use, and comfort among residents. Our findings demonstrate a need to improve EPT education in pediatric residencies.

    View details for DOI 10.1542/peds.2011-3764

    View details for PubMedID 22987881

  • IUDs and Adolescents An Under-Utilized Opportunity for Pregnancy Prevention JOURNAL OF PEDIATRIC AND ADOLESCENT GYNECOLOGY Yen, S., Saah, T., Hillard, P. J. 2010; 23 (3): 123-128

    Abstract

    Most pregnancies in adolescents are unintended and preventable if contraception were utilized. IUDs provide an under-utilized highly effective form of contraception. IUDs are appropriate for nulliparous women, including adolescents. IUDs do not increase: the incidence of Pelvic Inflammatory Disease after the 1st month of insertion, the odds of infertility, nor rate of ectopic pregnancy. Adolesecnts need more education about and increased access to IUDs. Practical points regarding IUD selection and insertion in adolescents are reviewed, including pain prophylaxis, anticipatory guidance, side effects and complications. In summary, IUDs are safe for contraception in most adolescents. IUDs are effective and eliminate the need for ongoing adherence and thus have the potential to decrease unplanned pregnancies.

    View details for DOI 10.1016/j.jpag.2009.09.004

    View details for Web of Science ID 000278173800002

    View details for PubMedID 19896396

  • EMERGENCY CONTRACEPTION KNOWLEDGE AMONG TEENS ETHNICITY & DISEASE Urena, E., Yen, S. 2009; 19 (2): S25-S27
  • Feasibility of a dance videogame to promote weight loss among overweight children and adolescents ARCHIVES OF PEDIATRICS & ADOLESCENT MEDICINE Madsen, K. A., Yen, S., Wlasiuk, L., Newman, T. B., Lustig, R. 2007; 161 (1): 105-107

    View details for Web of Science ID 000243273800018

    View details for PubMedID 17199076

  • Bacterial vaginosis in sexually experienced and non-sexually experienced young women entering the military OBSTETRICS AND GYNECOLOGY Yen, S., SHAFER, M. A., Moncada, J., Campbell, C. J., Flinn, S. D., Boyer, C. B. 2003; 102 (5): 927-933

    Abstract

    To estimate the prevalence of bacterial vaginosis by Nugent Gram stain criteria in a nonclinic national sample of young women entering recruit training; to examine clinical associations with bacterial vaginosis; and to evaluate the performance of a pH test card and Papanicolaou smear against Gram stain as screening tools for bacterial vaginosis.A cross-sectional study of 1938 women was conducted. Self-collected vaginal swabs were applied to a colorimetric pH test card and a glass slide for Gram stain evaluation according to the Nugent criteria. Papanicolaou smears and samples for sexually transmitted diseases screening were collected during routine entry pelvic examinations.Bacterial vaginosis prevalence was 27%, with 28% in sexually experienced and 18% in non-sexually experienced women (P = .001). Bacterial vaginosis prevalence was 11% in Asian/Pacific Islanders, which was lower than in other nonwhite ethnic groups (P = .004). Clinically, bacterial vaginosis was directly related to multiple sexual partners (P = .026), self-report of vaginal discharge (P = .001), self-report of vaginal odor (P < .001), and concurrent Chlamydia trachomatis infection (P = .002), and inversely related to hormonal contraceptive use (P = .013). Vaginal discharge did not achieve statistical significance in multivariate analysis. Compared with the Nugent criteria, the sensitivities and specificities for bacterial vaginosis diagnosis were as follows: colorimetric pH test: 72% and 67%; Papanicolaou smear: 72% and 79%, respectively.Among these diverse young women, bacterial vaginosis occurs commonly in both sexually experienced and inexperienced young women and differs by race and ethnicity. The pH colorimetric test and Papanicolaou smear performed moderately well as screening tools for bacterial vaginosis. The inverse relationship of bacterial vaginosis with hormonal contraceptive use and its direct relationship with C. trachomatis need further study.

    View details for DOI 10.1016/S0029-7844(03)00858-5

    View details for Web of Science ID 000186294400009

    View details for PubMedID 14672465