Sophia Yen, MD

  • “I take care of the entire patient, from head to toe.”

I chose pediatrics because I am all about prevention. Let's catch things early. Let's treat potential problems before they become big problems. One of my goals is to ensure that teenage girls and boys have access to comprehensive sexuality education and confidential reproductive health care. I also enjoy teaching patients and families how to prevent and treat diseases, pregnancy, and obesity.

The first visit might be the longest visit your child has ever had, but it will also be the most thorough. I like to take care of everything in one visit, so you don't have to keep coming back. Patients receive cutting-edge, up-to-date, evidence-based care at our clinic and, because we are an academic center, we can take more time with our patients. Our multi-disciplinary team also includes nutrition and social work.

I take care of the entire patient from head to toe, including the psychosocial aspects, including the unique challenges faced by teens such as acne, menses, and puberty. I want each patient to leave knowing that we have made sure all aspects of their health have been checked and their questions answered.

Especialidades médicas y/o especialidades quirúrgicas


Adolescent Medicine

Trabajo y educación


University of California at San Francisco School of Medicine, San Francisco, CA, 1997

Primeros años de residencia

UCSF Pediatric Fellowships, San Francisco, CA, 1998

Últimos años de residencia

UCSF Pediatric Fellowships, San Francisco, CA, 2000


UCSF Adolescent Medicine, San Francisco, CA, 2003

Certificado(s) de especialidad

Adolescent Medicine, American Board of Pediatrics



Adolescent Health

Birth Control

Menstrual Issues


PCOS (Polycystic Ovarian Syndrome)

Pregnancy Prevention

Todo Publicaciones

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


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

Improving adolescent knowledge of emergency contraception: challenges and solutions OPEN ACCESS JOURNAL OF CONTRACEPTION Seetharaman, S., Yen, S., Ammerman, S. D. 2016; 7: 16173


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 13-16years old and 70% were 17-25years old (mean age 17.8years); 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 1day 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

Improving adolescent knowledge of emergency contraception: challenges and solutions Open Access Journal of Contraception Seetharaman , S., Sophia, Y., Seth, A. D. 2016: 161-173


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

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


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

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)


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

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


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

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


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

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


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

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
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

View details for Web of Science ID 000243273800018

View details for PubMedID 17199076



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

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
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