Practice patterns and attitudes about treating abnormal uterine bleeding: A national survey of obstetricians and gynecologists

Abstract

Objective(s)

To examine the practice patterns and attitudes of obstetricians and gynecologists surrounding treatment of abnormal uterine bleeding (AUB).

Study Design

We conducted a cross-sectional study of members of the American College of Obstetricians and Gynecologists. Surveys, which were distributed using a sequential mixed method (both web-based and mail-based) approach, included questions about practice characteristics, practice patterns, and knowledge about treatment options for AUB.

Results

Four hundred seventeen out of 802 questionnaires were returned (52%). The most commonly selected first line choice for AUB treatment was combined oral contraceptives (97% anovulatory, 98% ovulatory). The levonorgestrel intrauterine system was the next most frequently selected option (63% anovulatory, 53% ovulatory). Respondents did not score high on questions about the effectiveness of treatments for AUB. Only 25% (n=86) answered at least two out of the three questions correctly.

Conclusions

Continued education is necessary to increase the utilization of the most effective treatment options for AUB.

INTRODUCTION

Menstrual disorders are the most common gynecologic conditions in the general population. (1) Abnormal uterine bleeding (AUB) can mean both heavy and irregular menstrual bleeding, and many patients experience the combination of these symptoms. (2) The substantial impact of abnormal uterine bleeding (AUB) lies not only in its prevalence, but its affect on quality of life, associated loss of productivity, and major health care costs. (3–5)

AUB contributes to approximately 400,000 hospitalizations and several times that number of ambulatory visits in the United States each year, and physicians encounter many challenges when delivering medical care to these women. (6) The multiple etiologies of AUB, numerous available medical and surgical treatment options, and inconsistent measurement and reporting of treatment outcomes in studies contribute to the confusing nature of the body of literature on AUB. This has resulted in a body of literature which can be difficult to interpret and translate to clinical decision-making. (7) Adding to those challenges, recent studies have highlighted major variations in how clinicians and researchers define the commonly accepted terminologies used to describe the clinical signs and causes of menstrual disorders. (8) Clinical practice guidelines for the medical management of AUB have not been published in the United States, though guidelines from the United Kingdom and New Zealand are available. (9–11)

Despite the prevalence of AUB and its significant impact on the quality of life of women, in the United States there is no standardized way of evaluating or treating women with this problem. The clinical guidelines published in other countries, which suggest a standardized way of treating women with AUB, are based on a comprehensive systematic review of the evidence on the relative effectiveness of each treatment option. This study was performed to examine the practice patterns and attitudes of obstetricians and gynecologists in the U.S. about medical treatment of women with AUB. We aimed to evaluate whether physicians were choosing the most effective treatment options for patients with AUB and their attitudes about the effectiveness of commonly used treatment options.

MATERIALS AND METHODS

We conducted a cross-sectional survey of members of the American College of Obstetricians and Gynecologists (ACOG) from October 2008 through May 2009. The study was approved by the Women and Infants Hospital Institutional Review Board. (IRB # 08-0093)

Questionnaires were sent to 802 ACOG members. Six hundred two recipients were members of the Collaborative Ambulatory Research Network (CARN), which is a group of practicing obstetrician-gynecologists who volunteer to participate in survey research. (12) The other 200 recipients were randomly selected ACOG members who had not received a survey from ACOG in the previous 2 years. Other ACOG studies which surveyed both CARN members and a random sample of ACOG members have found that CARN members had been in practice longer than non-CARN members, but that there were no differences between groups in terms of distribution of responses to the survey questions.(13) ACOG surveys typically achieve a 30–50% response rate; With at least 350 eligible responses, we would have the ability to detect at least a 15% difference in physician demographic characteristics with alpha 0.05 and power of 80%.

We distributed the surveys using a sequential mixed method approach; all potential participants with email addresses received a web-based version and then all potential participants without an email address or who did not respond to the web-based version received a mailed version. This approach has been described as a way to reduce non-response error, especially among web-based surveys. (14) We showed in a previous analysis of this web-based survey that this sequential mixed method approach provided adequate representation and that web-based data collection was an appropriate approach for surveying obstetricians and gynecologists. (15)

For the web-based version of the survey, we used DatStat Illume (DatStat Illume is a trademark of DatStat, Incorporated, Seattle, Washington) and designed the web-based survey using standards suggested by Crawford et al. (16) DatStat Illume, a sophisticated computer software package with excellent data security, allows for complex skip patterns. The content of the survey was the same for the web and paper-based surveys and included multiple-choice questions about the physician and his/her practice, practice patterns for the evaluation and treatment of AUB, inquiries about the concepts that should be included in a comprehensive AUB questionnaire, and awareness of the evidence (as of the time of the survey) on medical treatment options for AUB. Practice patterns for the treatment of AUB were assessed using case scenarios. (Figure 1) Respondents were asked to choose the top three treatment options they preferred for each clinical scenario. Questions evaluating awareness of the evidence on treatment options for AUB were based on Cochrane Collaboration reviews. (Figure 1) (17, 18, 19, 20) Both the web-based and the paper-based survey were reviewed by experts and critiqued by colleagues of the Principal Investigator. Initially, we conducted a pilot survey with 25 physicians at Women & Infants Hospital (Providence, RI). The questionnaire and protocol for participant contact were revised based on feedback from the pilot participants.

Figure 1.

Participant flow diagram

We followed principles of data collection recommended by Dillman and colleagues to maximize response rate (14, 21) First, pre-notification letters of the survey were mailed (n=802). (See figure 2) Ten days after the pre-notification letter, all study participants with a valid email address were sent an email invitation to participate in the web-based survey, which included an embedded link to a page that explained informed consent and included an embedded link to the secure and confidential website for survey completion. Four email reminders were sent to non-responders. For non-responders to the web-based survey as well as physicians with an unavailable e-mail address, a paper-based version of the survey was sent by mail six weeks after the pre-notification letters.

The informed consent page of the web-survey included information about the study, including the risks and benefits. Participants were asked to click a “button” at the end of page if they understood the study and consented to participate. For the paper survey, a letter containing information on informed consent was attached to the survey. The end of the letter addressed informed consent by the following: “By reading this letter, completing the paper survey, and submitting the paper survey, you are consenting to participate in this study”.

Web-based responses were automatically entered into the DatStat Illume Web database and surveys returned by mail were manually entered by a research assistant into the same DatStat software program that was used by study participants. Entered data were verified by the Principal Investigator and discrepancies were confirmed by a third reviewer.

Analyses were conducted using SAS 9.1 (Cary, NC). Categorical variables were compared using Chi square and Fisher’s exact tests, where appropriate, and two-sided p-values were calculated, with p<0.05 considered statistically significant.

RESULTS

Of the 802 physicians in the study sample, 697 (87%) had email addresses on file and were sent the web-based version of the survey. (Figure 2) Two-hundred ninety seven completed the web-based version (42.6%) and 120 physicians responded to the mail-based survey request (23.8%). In total, 417 questionnaires were returned, resulting in a response rate of 52.0%. Because the intent of the content of the survey was to examine obstetrician-gynecologists’ knowledge and practice patterns related to AUB, we excluded subspecialists, physicians who responded that they did not provide care for women with AUB, and physicians who returned the mail survey with a note that they were “retired” (n=53). A total of 364 surveys from obstetrician-gynecologists remained in our sample.

Overall, representation was obtained from all geographical districts and the sample was equally divided in terms of gender. (Table 1) Of respondents, the majority (69%) responded that they had completed residency 11 or more years ago, 53% reported that they evaluated 11 or more patients with heavy menstrual bleeding per month on average, and 53% of respondents indicated that they know of friends or family members who experience problems with heavy menstrual bleeding.

Table 1.

Respondent Demographics

Demographics		N (column %)a N=359b
Type of sub-specialty
General Ob-Gyn		337(94)
Reproductive Endocrinology Subspecialty		15(4)
Urogynecology		9(3)
Minimally invasive gynecology/laparoscopy		35(10)
Clinical Research		16(4)
Membership status
Collaborative Ambulatory Research Network Member (CARN)		293 (82)
Non-CARN member		66 (18)
Gender
Male		167(49)
Female		173(51)
Years since completing residency
< 5 years		25 (7)
5–10 years		82 (24)
11–20 years		94 (27)
> 20 years		143 (42)
Type of Practice
Private practice		283(82)
Community hospital faculty		16(5)
University hospital faculty		37(11)
Geographical Districts
Midwest		76(23)
Northeast		69(21)
South		116(36)
West		65(20)
Proportion of time providing direct patient care
0–50%		24(7)
51–75%		40(12)
76–100%		276(81)
Average number of patients evaluated per month with heavy Menstrual bleeding
1–10		165 (47)
11 or more		184 (53)
Average number of ablations performed per month
None		65 (19)
1–5		254 (73)
6 or more		30 (9)
Average number of hysterectomies performed per month
None		51 (15)
1–5		272 (78)
6 or more		27 (8)
Has friends or family members with heavy menstrual bleeding
Yes		182 (53)
No		104 (31)
Did not know		56 (16)
Median time to complete questionnairec		Median, IQR 14 minutes (8)

^aCould add up to > 100% because multiple choices could be selected

^bColumn may not add up to total (n= 359) because of skip patterns and item nonresponse

^cOnly for online surveys

For the case scenario on treatment of regular ovulatory heavy menstrual bleeding (Figure 1, Scenario A), the most commonly selected first line choices for treatment were COCs (97.7%) and the levonorgestrel intrauterine system (LNG-IUS) (62.7%), and nonsteroidal anti-inflammatory drugs (NSAIDs) (52.6%). (Table 2) We found that the prevalence of choosing COCs to treat ovulatory heavy menstrual bleeding did not differ by demographic and clinical practice factors. (Table 3) However, frequency of selection of LNG-IUS as a first line preference for treatment varied by type of practice. Ninety five percent of university hospital faculty chose it as a first line preference compared to 58% of private practice physicians (p=0.0001). Both physicians who completed residency greater than 20 years ago and men were less likely to choose NSAIDs as a first line agent than physicians who completed residency more recently and women. (p=0.002 and p=0.05, respectively) The most commonly selected first line preferences for treating anovulatory heavy menstrual bleeding (Figure 1, Scenario B) were COCs (96.5%), LNG-IUS (52.6%), and oral progestins (52.6%). (Table 2) The selection of oral progestins and LNG-IUS varied by type of practice; a higher proportion of private physicians than university hospital faculty chose oral progestins. (57% vs. 32%, p=0.01). (Table 3) Conversely, a higher proportion of university hospital faculty than private physicians chose the LNG-IUS. (78% vs. 50%, p=0.003)

Table 2.

Preferences for first line treatment for heavy menstrual bleeding^a

Treatments		N (%)b n=344
Non-emergent OVULATORY/REGULAR BLEEDING
Combined estrogen and progesterone therapy		336 (98%)
Non-steroidal anti-inflammatory drugs		181 (53%)
Oral Progestin		102 (30%)
Depot medroxyprogesterone acetate		84 (24%)
Levonorgestrel Intrauterine system		216 (63%)
Other medical optionsc		13 (4%)
Surgical optionsd		47 (14%)
Non-emergent ANOVULATORY/IRREGULAR BLEEDING
Combined estrogen and progesterone therapy		332 (96%)
Non-steroidal an ti-inflammatory drugs		77 (22%)
Oral Progestin		181 (53%)
Depot medroxyprogesterone acetate		93 (27%)
Levonorgestrel Intrauterine system		181 (53%)
Other medical optionsc		9 (3%)
Surgical optionsd		84 (24%)
ACUTE UTERINE BLEEDING IN A 38 YEAR OLD SMOKER
Combined estrogen and progesterone therapy		127 (37%)
Non-steroidal anti-inflammatory drugs		76 (22%)
Oral Progestin		208 (60%)
Depot medroxyprogesterone acetate		97 (28%)
Levonorgestrel Intrauterine system		98 (29%)
Estrogen single agent		96 (28%)
Dilation and curettage		246 (72%)
Endometrial ablation		95 (26%)
Hysterectomy		41 (12%)

^aRespondents were asked to select their top three choices for first line therapeutic options for three different case scenarios depicting ovulatory heavy menstrual bleeding, anovulatory heavy menstrual bleeding, and acute uterine bleeding. See Box 1 for a description of the case scenarios.

^bAdd up to more than 100% - respondents could choose up to three options

^cOther medical options include Danazol, single agent estrogen, GnRH agonists

^dSurgical options include dilation and curettage, endometrial ablation, and hysterectomy

Table 3.

Comparisons of the top three first line preferences for treatment of non- emergent OVULATORY heavy menstrual bleeding (shaded) and ANOVULATORY heavy menstrual bleeding (unshaded). Number and row percent who indicated each therapy by each demographic characteristic.

		OVULATORY HEAVY MENSTRUAL BLEEDING						ANOVLUATORY HEAVY MENSTRUALBLEEDING
		COCsa		LNG IUSa		NSAIDSa		COCsa		oral progestin		LNG IUSa
		n=336b	P	n=216b	P	n=181b	P	n=332b	P	n=181b	P	n=181b	P
Years since residency
< 5 years		24 (96)	0.20	18 (72)	0.29	15 (60)	0.002	23 (92)	0.49	7 (28)	0.05	12 (48)	0.38
5–10 years		80 (98)		57 (70)		52 (63)		79 (96)		43 (52)		49 (60)
11–20 years		94 (100)		57 (61)		56 (60)		92 (98)		48 (51)		51 (54)
> 20 years		138 (97)		84 (59)		58 (41)		138 (97)		83 (58)		69 (48)
Type of Practice
Privatec		276 (98)	1.0	163 (58)	0.0001	144 (51)	0.25	272 (96)	0.55	160 (57)	0.01	141 (50)	0.003
Communityd		16 (100)		12 (75)		11 (69)		15 (94)		7 (44)		6 (38)
Universitye		36 (97)		35 (95)		23 (62)		37 (100)		12 (32)		29 (78)
Geographic Districts
Midwest		75 (99)	0.14	52 (68)	0.77	39 (51)	0.98	74 (97)	0.65	36 (47)	0.67	46 (61)	0.15
Northeast		68 (99)		42 (61)		37 (54)		67 (97)		39 (57)		29 (42)
South		115 (99)		73 (63)		59 (51)		114 (98)		64 (55)		61 (53)
West		61 (94)		40 (62)		33 (51)		62 (95)		35 (54)		36 (55)
Gender
Male		161 (96)	0.17	98 (59)	0.11	78 (47)	0.05	164 (98)	0.08	87 (52)	0.92	85 (51)	0.52
Female		171 (99)		116 (67)		99 (57)		164 (95)		91 (53)		94 (54)

^aAbbreviations: COCs – combined oral contraceptives, LNG-IUS – levonorgestrel intrauterine system, NSAIDS – Nonsteroidal anti inflammatory drugs

^bNumbers in columns do not always add up to the column total given item nonresponse

^cPrivate practice

^dCommunity hospital faculty

^eUniversity hospital faculty

Physicians selected surgical options more than any other option for the treatment of acute uterine bleeding in a 38 year old smoker (80%). (Figure 1, Scenario C) (Table 2) Preferences for treatment of this patient with acute uterine bleeding did not differ by years since completing residency, type of practice, geographic district or gender. (data not shown)

Data were analyzed for three questions which assessed awareness of the current evidence on treatment options for AUB. Correct answers were devised from Cochrane Reviews. (17–20) Only 25% (n=86) answered at least two out of the three questions correctly. We analyzed whether or not demographic factors or clinical volume were associated with the number of correct responses to the knowledge questions. We found only one difference; physicians in university hospital practice were more likely to answer at least 2 out of 3 questions correctly (36%) than private practice physicians (23%, p=0.04).

In terms of the individual questions, nearly all physicians responded correctly that LNG-IUS is an effective treatment for heavy menstrual bleeding (n=336, 98%). For the question about treating patients with ovulatory heavy menstrual bleeding with 14 days of oral progestins, only 23% responded correctly that it was ineffective. Forty seven percent of physicians who selected progestins as a first line treatment were unsure of the Cochrane Collaboration’s conclusion about their effectiveness and 23% of physicians incorrectly thought they were found to be effective. Regarding physicians’ knowledge of a systematic review of treating patients with ovulatory heavy menstrual bleeding with COCs, 22% of respondents were unsure of the conclusions of the review and 74% responded incorrectly that the systematic review concluded that COCs were effective.

COMMENTS

AUB, a prevalent symptom among women in the United States, affects quality of life, ability to work, and healthcare costs.(1,3,4) However, little is known about how American obstetrician-gynecologists treat this symptom in the clinical encounter and standard guidelines have not been implemented in the United States to guide evidence-based treatment of heavy or irregular menstrual bleeding Our study of obstetricians and gynecologists who were members of ACOG had two major findings (1) participants most frequently selected COCs for the treatment of both ovulatory and anovulatory heavy menstrual bleeding; and (2) participants overall lacked awareness of the current (as of October 2008–May 2009) evidence on effectiveness of frequently utilized treatment options for AUB.

Respondents to the survey most frequently chose COCs as a preference for first line treatment for both ovulatory (97.7%) and anovulatory (96.5%) heavy menstrual bleeding. The LNG-IUS was selected as a first line treatment less frequently (62.7% and 52.6%). This finding does not reflect the recommendation of the clinical guidelines for treatment of heavy menstrual bleeding published in the United Kingdom in 2007 or the previous guidelines published in 1999. (9, 22) Based on systematic review of the evidence, the 2007 guidelines from the National Institute of Clinical Excellence recommends that the LNG-IUS be chosen above all other treatment options because of its effectiveness in reducing bleeding (71–96%) and the quality of the evidence on its effectiveness.(9) Combined oral contraceptives, tranexamic acid, or NSAIDs were suggested as second line options. This was a change from the 1999 National Evidence Based Guidelines from the Royal College of Obstetricians and Gynecologists (RCOG) which suggested that nonhormonal treatments (tranexamic acid or NSAIDs) be chosen as the first treatment option for patients with heavy menstrual bleeding. (22) A 2006 survey of gynecologists on endometrial ablation conducted in the United Kingdom showed that only 0.4% chose COCs as a first line treatment for heavy menstrual bleeding, 78.7% chose nonhormonal treatment (tranexamic acid or NSAIDs), and 20.7% chose the LNG-IUS, which was consistent with 1999 United Kingdom guidelines. (23) In addition to these differences between U.S. and U.K. study populations, we saw differences between physicians within our own study on preferences for treatment.

Our study is not the first to show differences in diagnosis and management of common medical problems between the United States and United Kingdom. (24, 25) Countries with clinical practice guidelines and easily accessible evidence based reviews likely manage patients more similarly to one another and differently from countries without clinical practice guidelines.(24) Guidelines for the management of heavy menstrual bleeding were published in the United Kingdom in 1999 and in 2007. (9, 22) The United States does not currently have clinical practice guidelines for the medical management of heavy or irregular menstrual bleeding.

Deciding on the best medical therapy for AUB can be quite challenging because of the numerous treatment options available. (7) Physiologically it makes sense that COCs, the most frequently chosen treatment option in this study, should effectively reduce menstrual bleeding. Materials published by ACOG suggest that COCs can be effective for the treatment of heavy menstrual bleeding. (26) However, systematic reviews conducted by the Cochrane collaboration found insufficient evidence to support the effectiveness of COCs in treating ovulatory or anovulatory heavy menstrual bleeding.(19, 20) At the time the systematic review was published in 2009, only one small study showed that COCs reduced menstrual bleeding by 43%, and evidence supporting the effectiveness of COCs was limited. (27) However, since that publication (and after our study was completed), three randomized clinical trials on the effectiveness of COCs for women with heavy menstrual bleeding were published. Two of these studies found that although COCs decreased the amount of menstrual blood lost, they were less effective than the LNG-IUS. (28,29) The other study found that 44% of women with heavy menstrual bleeding who were treated with a novel COC preparation experienced completely normal menstrual periods after treatment. (30). Another commonly used medical treatment for AUB, oral progestin, has been shown to be ineffective for ovulatory heavy menstrual bleeding if used in just the luteal phase (for 10–14 days of the menstrual cycle) but may be effective if used for 21 days of the cycle.(17, 18) Confusion surrounding terminologies for describing AUB, the two slightly different regimens (10–14 days versus 21 days for oral progestins), and the fact that luteal phase progestins are approved by the Food and Drug Administration for the treatment of AUB may have contributed to why physicians may have answered the question on luteal phase progestins incorrectly. (8)

Though some treatments have been compared head-to-head, many treatments have not been compared to one another and clinicians may be interpreting the available literature differently. Systematic reviews and clinical guidelines can help clarify the literature when it is inconsistent. Although Cochrane reviews have been published on oral progestins, COCs, the LNG-IUS, NSAIDS, and antifibrinolytics, these reviews may be underutilized by physicians because they do not have access to them or may be intimidated by the sheer length of the reviews.(17–20, 31–33) The results of our study suggests that obstetricians and gynecologists in the United States may not be accessing these evidence based reviews given our findings that participants in our study were unaware of the conclusions of the reviews on COCs and luteal phase progestins. Although 98% of respondents correctly answered that the LNG-IUS is an effective treatment for heavy menstrual bleeding and the evidence on effectiveness of the LNG-IUS is high quality, the LNG-IUS was chosen less frequently than COCs as a first-line treatment. Access to the LNG-IUS could potentially affect physician choice of treatment options, though to our knowledge there is no evidence supporting access as a reason for less prescribing of the LNG-IUS for heavy menstrual bleeding. National published guidelines or emphasis of these already published international guidelines by professional organizations, such as the American College of Obstetricians and Gynecologists could potentially improve physician knowledge on AUB and increase their utilization of more effective treatments for patients with AUB.

This study had several strengths. First, the data represent responses from a national sample of gynecologists with good representation from all geographic districts. Second, adequate “coverage” of the intended study population was achieved given that email addresses were available for 87% of the study sample. However, while our response rate was relatively high for recent physician surveys, still 47% of physicians did not respond, resulting in some potential response bias. Also, we only assessed awareness of the current body of evidence pertaining to COCs, oral progestins, and the LNG-IUS, which we anticipated would be the most commonly selected treatment options based on our clinical experience. Therefore, we cannot evaluate level of awareness of the body of evidence on other treatment options, such as antifibrinolytics, NSAIDs, and endometrial ablation.

Physician surveys provide important information about knowledge, practice patterns, and attitudes. Our survey suggests that U.S. obstetricians and gynecologists may treat patients with AUB differently than obstetricians and gynecologists in other countries, choosing less effective treatment options over more effective options based on the current available evidence. Additionally, treatment preferences did not necessarily reflect knowledge about the effectiveness of the options. These findings highlight the need to develop or more effectively disseminate educational materials and practice guidelines on evidence based treatment of AUB.

Box 1. Case scenarios and questions on awareness of the evidence on treatment options for AUB.

CASE SCENARIOSa

The following two items refer to patients who DO NOT require emergency treatment of heavy menstrual bleeding. b Assume that the patient has no contraindications for any of the listed therapeutic options.c (A)For a 30 year old patient who has heavy and REGULAR menstrual bleeding and who has tried no therapy yet, please select up to three of the following that you would most likely prescribe as your first line of treatment. (B)For a 30 year old patient who has heavy and IRREGULAR menstrual bleeding and who has tried no therapy yet, please select up to three of the following that you would most likely prescribe as your first line of treatment.

The following item refers to patients who DO require emergency treatment of heavy menstrual bleeding.d (C)Consider the following: A 38 year old cigarette smoker who has an episode of acute uterine bleeding and who has tried no therapy yet. Please select the top three treatments which you would consider giving to this patient.

ASSESSMENT OF AWARENESS OF THE EVIDENCE ON AUB TREATMENT OPTIONS (1)A Cochrane review made what conclusion about treating ovulatory heavy menstrual bleeding with combined oral contraceptivese

(2)A Cochrane review made what conclusion about treating ovulatory heavy menstrual bleeding with cyclic (14 days) of oral progestine (3)The levonorgestrel intrauterine system is effective for the treatment of menorrhagiaf

^aFor all case scenarios, respondents were asked to assume that the patient did not have endometrial hyperplasia or cancer

^bRespondents were instructed that emergency treatment of heavy menstrual bleeding is defined as a situation in which you feel a patient with acute heavy bleeding necessitates an emergency room evaluation, and/or hospital admission, and/or blood transfusion, and/or immediate medical or surgical intervention

^cResponse options included combination estrogen-progestin therapy (pills, patch, ring) equivalent of once per day, danazol, estrogen (single agent), GnRH agonist, non-steroidal anti-inflammatory drugs, oral progestin once daily for 14 days/month, oral progestin once daily for 21 days/month, intramuscular progestin (Depo-medroxyprogesterone acetate), levonorgestrel intrauterine system, dilation and curettage, endometrial ablation, hysterectomy

^dResponse options for “emergency treatment” included all of the options listed above in “c” plus combination estrogen-progestin therapy equivalent to more than one pill per day, intrauterine balloon, and oral progestin equivalent to multiple doses daily

^eResponse options included effective, NOT effective, there is not enough evidence to make a conclusion, unsure

^fResponse options included true, false, there is not enough evidence to make a conclusion, unsure