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Obstetric Anesthesiology: Research Report

Obstetric Anesthesia Workforce Survey: A 30-Year Update

Traynor, Andrea J. MD*; Aragon, Meredith BA; Ghosh, Debashis PhD; Choi, Ray S. MD; Dingmann, Colleen RN, PhD; Vu Tran, Zung PhD; Bucklin, Brenda A. MD

Author Information
doi: 10.1213/ANE.0000000000001204

“The position of a woman in any civilization is an indication of the advancement of that civilization; the position of a woman is indicated by the care given her at the birth of her child.”1 Numerous changes in both obstetric care and a woman’s expectations for her childbirth experience have occurred since this statement was published in 1929. Anesthesiologists would be remiss if there were not continual attempts to assess and improve parturients’ health care. It is, after all, a reflection of a woman’s position in the society. Every 10 years since 1981, a survey has been conducted to assess current obstetric anesthesia practice and workforce coverage in the United States.2–4 These decennial surveys have facilitated the study of the evolution of obstetric anesthesiology, including identification of areas for improvement in the future care of pregnant patients.

The first survey was published in 1981 and demonstrated that epidural analgesia was performed by obstetricians in 30% of cases.4 The overall conclusion of that survey was that availability of neuraxial labor analgesia needed improvement. Providers responded to this need, and the 1991 survey showed not only that the availability of epidural labor analgesia increased, but that it was most often performed and managed by anesthesiologists.3 Despite the increased availability, neuraxial labor analgesia was reported to be unavailable in 20% of the smallest hospitals (<500 births per year). In the 2001 survey, the use of neuraxial labor analgesia and availability of providers increased further. The largest increase was seen in the smallest hospitals, with 95% of responding hospitals reporting availability of neuraxial labor analgesia in 2001.2

Although neuraxial labor analgesia is an important component of obstetric anesthesia practice, many other factors are involved in optimal care of the parturient. These include availability of massive transfusion protocols (MTPs) to treat the increasing rate of obstetrical hemorrhage, availability and quality of postpartum care including tubal ligation, and life-support training for labor and delivery nurses.5,6 The aim of this 2011 Obstetric Anesthesia Workforce Survey (performed in 2012) was to provide an indication of changes over time in the provision of procedures such as labor analgesia and cesarean delivery (CD) anesthesia. Our primary hypothesis was that there have been significant changes in anesthesia staffing of labor and delivery units since the last survey 10 years ago, as reported by responding hospitals. An additional aim was to inquire about other aspects of essential care of the parturient in an effort to assess the overall status of obstetric anesthesia care in the United States.


In 1981, 1992, and 2001, obstetric anesthesia workforce surveys were conducted to assess trends in obstetric anesthesia practice. This 2011 survey was modified from the 2001 survey with the addition of questions to define and address current practices. The major difference between the 2011 survey and all other previous surveys was the use of an electronic survey instrument, Survey Monkey (, to distribute the survey.

In the previous surveys, the survey instrument was sent by mail to key labor and delivery personnel (Chief of Anesthesiology, Chief of Obstetrics, and Labor and Delivery Manager). Because the highest response rate in previous surveys was from the Chief of Anesthesiology, and because of anesthesia-specific questions contained in the survey, the current survey was sent by email to either the chief of anesthesiology or the chief of obstetric anesthesia. By using the response rate from previous surveys, the number of individuals contacted within each stratum was determined with the expectation that approximately 170 individuals in each stratum would complete the survey.

After Colorado Multiple IRB approval (COMIRB Protocol #11–1755, University of Colorado Denver Anschutz Medical Campus), and based on the sample size from previous surveys, a stratified random sample of 1193 hospitals was selected (from a total of 2900) using the database from the American Hospital Association’s (AHA) Guide® to the Health Care Field 2012 Edition. Hospitals were selected using a stratified (by geographic regions and number of hospital births) random sampling scheme. The geographic stratum was the 9 US Census Bureau’s Regions and Divisions (Northeast, Mid-Atlantic, South Atlantic, East North Central, East South Central, West North Central, West South Central, Mountain, and Pacific;, and the number of births per stratum was reported for each hospital in the AHA guide (stratum I, >1500 births; stratum II, 500–1499 births; and stratum III, <500 births). A total of 341 stratum I hospitals, 438 stratum II hospitals, and 414 stratum III hospitals were randomly selected using this sampling scheme to guarantee approximately 170 individuals in each stratum completing the survey based on the historical stratum-specific response rates. The goal was to collect approximately the same number of responses as previous surveys.

Each randomly selected hospital was contacted through phone up to 3 times by the research staff (medical student or research nurse) to identify the contact person in the anesthesia group providing obstetrical anesthesia services. After contact information was obtained, a physician investigator (AJT or BAB) personally contacted the anesthesia provider to ask him or her to provide an email address to which we were to send the survey. The anesthesia provider was contacted up to a maximum of 3 times. When an email address was obtained, an email was sent up to a maximum of 3 times to the anesthesia provider over a 3-month period. Emails were sent to all providers identified as the primary provider of obstetric anesthesia services whether or not they were contacted directly by phone. In some cases, the name and email address was given to the research staff by the hospital, operating room, or anesthesiology department administration. This email explained the purpose and objectives of the survey and provided a link to the appropriate Survey Monkey survey. (, and these are also included as Supplemental Digital Content ( The survey contained 47 questions and required approximately 15 to 17 minutes to complete. Written informed consent was implied by completion of the survey.

Results were analyzed using the R statistical package (R Core Team 2015; R: A language and environment for statistical computing. R Foundation for Statistical Computing, Vienna, Austria, Analyses consisted of calculating frequency distributions for categorical variables. We used χ2 statistics to test for differences in proportions equaling 0 across groups. All statistical inferences were performed at a significance level of 0.05.

A major issue in the study was the presence of missing data. Missingness came from 2 sources: survey nonresponse and item nonresponse. The former refers to providers who refused participation in the study, whereas the latter refers to providers skipping individual questions on the survey. Survey nonresponse was modeled using Horvitz-Thompson estimators, which weight responses by the inverse of the probability of response. We assumed stratum-specific weights in our modeling. On the basis of the weighted proportion estimators, we calculated the lower and upper limits of the 95% confidence interval (CI) for a proportion, using the Wilson procedure with a correction for continuity.7 To account for item missingness, we conducted sensitivity analyses in which we assumed all missing items were coded as “yes” in the surveys. We then reran the Horvitz-Thompson analysis and found that, in most instances, it did not qualitatively change conclusions (data not shown).

The Horvitz-Thompson estimators are used in surveys to perform superpopulation inference, and when those are reported, the inferences are to a generalized population. However, previous survey analyses used finite-population inferential methods, which only referred to the survey responders. In situations where it was not possible to obtain the raw data for comparison (e.g., previous versions of the survey), we used finite population inferential methods.

Sample sizes for this survey were based on the previously published survey results.2–4 The number of hospitals previously included and the surveys returned were part of the current estimates.


Number of Hospitals Providing Obstetrical Care

Table 1 contains data aggregated from the 2012 AHA Guide to the Health Care Field, which contains data from 2011 as reported by member hospitals.

Table 1.
Table 1.:
Number of Hospitals Providing Obstetrical Care by Annual Number of Births
Table 2.
Table 2.:
Numbers of Contacts Across Strata

Table 2 shows the number of contacts across strata. Three percent of hospitals contacted no longer had an obstetrics (OB) department, despite reporting the presence of an OB department in the 2012 AHA guide, with the highest rate of OB department attrition in this survey reported by stratum III hospitals (7%). Clinicians from 6% of hospitals refused participation outright. Fourteen percent of hospitals could not provide a valid email address for an obstetric anesthesia provider. Multiple reasons were given for not providing an email address, including not knowing the physician’s email, rural area without email access, and hospital staff who were unaware of the obstetric anesthesia providers. A total of 872 email addresses were obtained. Of these, 8% were not delivered (i.e., were not valid email addresses). Of the 1193 hospitals with valid email addresses for the lead OB anesthesia provider to whom the survey link was sent, the response rates were 56% (stratum I), 29% (stratum II), and 33% (stratum III). The response rates differed among the 3 strata (χ2 test: test statistic = 78.6, P < 0.0001).

Description of Respondents and Profile of Responding Hospitals

Table 3.
Table 3.:
Description of Respondents and Profiles of Responding Hospitals

Table 3 describes the numbers of surveyed hospitals’ respondents and hospital characteristics. Twenty-eight percent of stratum I hospitals reported having an anesthesiology residency program and 57% considered themselves a regional referral center for high-risk OB. Only 10% of responding stratum II hospitals considered themselves referral centers for high-risk parturients, compared with 20% of responding hospitals in the 2001 survey.

24-Hour Availability of Neuraxial Labor Analgesia

Table 4.
Table 4.:
Availability of Neuraxial Labor Analgesia

Our primary hypothesis was that there have been significant changes in anesthesia staffing of labor and delivery units since the last survey 10 years ago, as reported by responding hospitals. Table 4 describes the 24-hour availability of neuraxial labor analgesia. In the largest hospitals, 86.3% (95% CI = 82.7%–90.0%) of clinicians reported in-house availability and none reported that neuraxial labor analgesia was unavailable. Respondents in stratum II and III hospitals reported higher rates of in-house availability than in the previous surveys: 41% (95% CI = 36.4%–45.7%) in stratum II and 15% (95% CI = 11.4%–18.2%) in stratum III. Although no respondents in either stratum I or II hospitals reported that neuraxial analgesia was unavailable, no availability was reported by 1% of the stratum III respondents.

Independent Certified Registered Nurse Anesthetists Practice

Figure 1.
Figure 1.:
Independent Certified Registered Nurse Anesthetist (CRNA) practice. Shaded box on left represents data before 2001 survey when practitioners were queried about CRNAs’ supervision by a nonanesthesiologist physician. After 2001, the survey specifically queried about independent CRNA practice without physician supervision.

Figure 1 represents changes over time in the practice of Certified Registered Nurse Anesthetists (CRNAs). In the 1981 and 1991 surveys, respondents were asked about CRNA practice supervised by a nonanesthesiologist physician (e.g., surgeon or obstetrician). In 2001, the survey was changed to reflect the response in the workforce to the changes in regulations that allowed CRNAs to practice independently without physician supervision. In this survey, respondents at hospitals with <500 deliveries reported that over two-thirds of the obstetric anesthesia care was performed by independently practicing CRNAs. In addition to practicing independently on labor and delivery, most of the CRNAs had other responsibilities in addition to the obstetrical unit. For example, 22% (95% CI = 4.2%–40%) of respondents in stratum II and 58% (95% CI = 34.4%–79.3%) of respondents in stratum III reported that labor and delivery on nights and weekends was covered by independently practicing CRNAs with other responsibilities.

Types of Analgesia Provided for Labor

Table 5.
Table 5.:
Types of Analgesia Provided During Labor and Anesthetic Techniques for Cesarean Delivery

Table 5 describes the types of anesthesia and analgesia provided during labor and CD. As in previous surveys, the use of neuraxial anesthesia at responding hospitals has continued to increase. The rates of epidural labor analgesia in responding hospitals ranged from 71% (stratum I) to 49% (stratum III). The use of combined spinal-epidural (CSE) analgesia was reported to be between 15% and 18% across all 3 strata. Availability and use of patient-controlled epidural analgesia (PCEA) was reported to be 82% in stratum I hospitals with an overwhelming majority of patients using it at hospitals where it is available. The overall rate of neuraxial labor analgesia use was 82% (stratum I), 74% (stratum II), and 66% (stratum III).

Vaginal Birth After Cesarean Delivery and Trial of Labor After Cesarean

Table 6.
Table 6.:
Vaginal Birth After Cesarean Delivery

Table 6 describes the anesthesia provider staffing for trial of labor after cesarean (TOLAC). According to respondents, the number of hospitals allowing TOLAC was lower across all strata than what was reported in the 2001 survey. Stratum I rates were 87.6% (95% CI = 84.1%–91.1%), but stratum II and III rates were 59% (95% CI = 54.3%–63.6%) and 43% (95% CI = 38.4%–48.0%), respectively. The number of stratum I respondents reporting that their hospital required the presence of an anesthesiologist or CRNA for TOLAC was ≥89%, regardless of whether neuraxial analgesia was used. Survey respondents reported that an obstetrician was required to be present “in-house” at most hospitals, ranging from 84% in stratum I to 69% in stratum III.

Hospitals Requiring Platelet Counts Before Neuraxial Labor Analgesia

Forty-three percent (95% CI = 38.2%–48.7%) of responding anesthesia providers in stratum I hospitals required evaluation of platelet counts before placement of neuraxial analgesia for labor. Sixty-three percent (95% CI = 58.6%–67.7%) and 67% (95% CI = 62.5%–71.6%) of respondents in stratum II and III hospitals required platelet counts, respectively.

Emergency Practices

Respondents in stratum I hospitals (76%, 95% CI = 71.9%–80.9%) were most likely to report MTP use compared with 42% (95% CI= 37.5%–46.7%) in stratum II and 42% (95% CI = 37.3%–46.8%) in stratum III hospitals. Respondents in stratum I hospitals were also most likely, in general, to report availability of all types of difficult airway equipments.

Reported rates of requirements for nurses for formal training in caring for postanesthesia patients were similar across all strata: 62% (95% CI = 57%–67%) in stratum I, 56% (95% CI = 52.2%–61.5%) in stratum II, and 56% (95% CI = 52.0%–61.6%) in stratum III.

Postpartum Tubal Ligation Practices and Availability

Reported postpartum tubal ligation (PPTL) availability rates were similar across strata (76% in stratum I, 70% in stratum II, and 78% in stratum III). Respondents reported that they were most likely to be performed >12 hours postpartum, with relatively few being performed 6 weeks postpartum across all 3 hospital strata (range, 9%–15%). These procedures were most likely to be performed under general anesthesia at stratum III hospitals, where respondents reported the use of general anesthesia in 55% of cases. At larger hospitals, respondents reported a general anesthesia rate of 22%. Inadequate staffing was reported to interfere with completion of a PPTL at larger hospitals, with 8% of anesthesia providers in stratum I hospitals reporting inadequate staffing “always” and 6.2% reporting problems “on nights and weekends” for these surgeries. No respondents in stratum III hospitals reported “always” having difficulty with inadequate staffing for PPTL surgeries.


Our primary hypothesis was that there have been significant changes in anesthesia staffing of labor and delivery units since the last survey 10 years ago, as reported by responding hospitals. The 1981 and 1991 surveys concluded that availability of neuraxial labor analgesia needed improvement.2,3 In the 1981 survey, in-house labor analgesia was reported to be available at 43% of stratum I hospitals, and in the 1991 survey, respondents reported 75% availability. In the smaller stratum III hospitals, 3% of responding hospitals in both surveys reported in-house obstetric anesthesia services. Furthermore, 33% of responding stratum III hospitals in 1981 and 20% of responding stratum III hospitals in 1991 reported that neuraxial labor analgesia was unavailable. Availability of neuraxial analgesia was reported at much higher rates in 2001, with 3% of stratum III hospitals reporting unavailability of neuraxial labor analgesia. In this survey, respondents reported that neuraxial labor analgesia is now available 24 hours per day at virtually all hospitals surveyed, including those with <500 deliveries per year (stratum III). Many responding anesthesia providers are providing this service by taking in-house call, with in-house coverage was reported at 80% in stratum I and 15% in stratum III.

In the 2001 survey, CSE labor analgesia was a new technique used in <10% of responding hospitals. CSE labor analgesia is associated with improved maternal satisfaction, epidural catheter success, and fewer epidural top-ups during first-stage labor.8–11 Disadvantages include an untested epidural catheter for the duration of the intrathecal dose and the necessity for additional equipment, namely the spinal needle. In this survey, respondents reported CSE use across strata, but it was used for <20% of neuraxial anesthetics. Interestingly, larger volume hospitals did not report a higher rate of CSE use.

PCEA was a recent advancement in the 2001 survey, with use in only 35% of stratum I hospitals. PCEA is associated with decreased provider workload and increased patient satisfaction.12,13 The use of PCEA was reported to be much higher in this survey and was used at 82% of responding hospitals with >1500 deliveries per year.

In 1999, the American College of Obstetricians and Gynecologists (ACOG) issued a statement that anesthesia providers should be “immediately available” for patients attempting a TOLAC.14 Since this statement, vaginal birth after cesarean delivery (VBAC) has been an important consideration for coverage of anesthesia services at hospitals offering TOLAC. Some hospitals do not allow TOLAC because of difficulties with providing immediate availability of anesthesiology services. In the 2001 survey, 98% of stratum I and 92% of stratum II hospitals reported availability of TOLAC, but approximately 80% of respondents in both strata said that hospital policy for anesthesiology availability had resulted in a decrease in VBAC attempts. In this survey, 65% of respondents in stratum II reported that TOLAC was allowed at their hospital and less than half of respondents at stratum III hospitals reported the availability of TOLAC. The majority of respondents in all strata reported that their hospital requires in-house presence of an anesthesia provider when a TOLAC is attempted, whether or not the patient has decided to receive neuraxial labor analgesia. An National Institutes of Health Consensus Conference consisting of a multidisciplinary panel of providers, including an obstetric anesthesiologist, convened in 2010 to discuss barriers to TOLAC. The panel determined that the decreasing number of hospitals providing TOLAC and the requirement for in-house coverage by anesthesia personnel might leave patients no option other than elective repeat CD or traveling long distances to find a hospital providing TOLAC.15 The results of our survey support this statement. CD rates are now >30%.16 ACOG has issued the statement, “At an individual level VBAC is associated with decreased maternal morbidity and fewer complications in future pregnancies. At a population level, VBAC is also associated with a decrease in the overall cesarean delivery rate.”17 Furthermore, a 2014 consensus statement by 2 major obstetric societies called for dramatic reductions in CD rates.18 Studies should be performed to determine the barriers to TOLAC, especially at smaller hospitals, and additional multidisciplinary discussions undertaken to determine methods to decrease cesarean deliveries.

A 2010 study demonstrated that 47% of women who desired PPTL, but did not undergo the procedure while in the hospital, had an unwanted pregnancy within 1 year of hospital discharge.19 ACOG subsequently issued a Committee Opinion on tubal ligation surgery stating: “Given the consequences of a missed procedure and the limited time frame in which it may be performed, postpartum sterilization must be considered an urgent surgical procedure.”20 Our survey results show that availability and staffing of obstetric anesthesia services for PPTL need improvement. Approximately 20% of responding clinicians in stratum I hospitals reported anesthesia staffing problems at night and on weekends. Awareness of potential public health ramifications because of lack of availability of personnel to provide anesthesia services for PPTL should be a topic for further education and improvement.

Previous surveys found fewer hospitals providing obstetric services than what was reported in the AHA guide.2,3 This survey is no exception; 6.5% of the smallest hospitals surveyed reported that they had discontinued obstetric services during that year. The larger hospitals did not report discontinuation of obstetrical services as frequently. This likely represents consolidation of obstetric services, which may require patients in the rural areas to travel long distances to obtain hospital-based obstetric services.

The American Society of Anesthesiologists Guidelines for Obstetric Anesthesia Practice state that routinely checking a platelet count is not necessary in otherwise healthy parturients before labor analgesia.21 Despite these guidelines, three-quarters of responding providers in stratum II and III hospitals required platelet counts before initiating neuraxial labor analgesia. This is important from a cost standpoint; unnecessary laboratory tests cost money. In addition, patients may not receive neuraxial labor analgesia if practitioners are waiting for a platelet count. It is unclear whether this practice is because of the lack of knowledge about the American Society of Anesthesiologists guidelines or if practitioners feel they must ensure a normal platelet count for fear of litigation. Regardless, this represents an opportunity for education and further studies on barriers to parturients receiving neuraxial analgesia in labor.

Severe maternal morbidity among delivery and postpartum hospitalizations is increasing, with 1 recent report finding that maternal morbidity increased 75% over 10 years.22 Thus, life-support training and planning have become important topics in OB and health care overall.23–25 Inadequate basic knowledge of obstetric cardiopulmonary resuscitation has been demonstrated among physicians caring for parturients.26,27 A 2009 survey of postanesthesia care requirements on obstetric anesthesia units reported that 20% of hospitals averaging 2500 deliveries per year did not require advanced or basic cardiac life support training for nurses.28 In our current survey, labor and delivery nurses were required to have training in the care of postsurgical patients at approximately three-quarters of responding hospitals. This was similar across strata, with smaller hospitals reporting the requirement for nurses to obtain education in the care of postanesthesia patients at the same rate as larger hospitals. The fact that not all hospitals require emergency cardiac life support training for nurses represents another area for improvement in the care of the parturient.

Postpartum hemorrhage (PPH) is the leading cause of maternal death worldwide, accounting for one-quarter of all maternal deaths and the leading cause of postpartum intensive care admission in the United States.29,30 Although the incidence varies widely depending on the criteria used to define PPH, reports suggest that it is increasing, even in high-resource countries.31 Implementation of MTPs for obstetric hemorrhage is a recent advance in emergency management of PPH. The use of MTPs is associated with faster resolution of maternal bleeding, reduced blood product use, decreased coagulopathy, and improved staff perception of patient safety.32,33 In our survey, 42% of respondents in strata III hospitals and 76% of respondents in strata I hospitals have an MTP for OB. More studies should evaluate barriers to implementation of MTP for OB, especially at smaller, lower resource, and rural hospitals.

In 2001, the Centers for Medicare and Medicaid services allowed individual states to opt out of the requirement that a physician oversee the provision of anesthesia services by CRNAs for the service to be reimbursed. As of July 2015, 17 states have opted out of physician supervision of CRNAs. Perhaps as reflection of this change in law, our survey shows a change in anesthesia personnel from the previous surveys. In this survey, reported coverage of labor and delivery services by independent CRNAs was highest in hospitals with <500 deliveries per year. In those hospitals, 68% of respondents reported that obstetric anesthesia services are performed at their hospital by CRNAs practicing independent of physician supervision. Independent CRNA practice is a controversial, and often emotionally charged, topic. Some question whether the quality of care differs between physician anesthesiologists, or anesthesia teams (physician and CRNA) and independent CRNA practice. Given that the current survey found that independent CRNA obstetric anesthesia practice is common, especially at hospitals with low volume labor and delivery units, it may be possible to study the outcome differences between these models of practice.

This survey was methodologically different from the previous surveys because it was distributed electronically. Given most physicians’ use of technology, changing from a mail-in survey to a computer-based survey was essential for ensuring an adequate response rate. This change brought significant methodologic challenges. Specifically, it was difficult to determine who should receive the survey email based solely on hospital name. Therefore, we implemented the methodology of personal phone calls to the hospital, anesthesia group, and anesthesia provider. In addition, our IRB insisted on complete anonymity of survey respondents. This limited our ability to follow-up with hospitals, analyze the data by geographic regions, or to make comparisons between responses by CRNA and physician.

One of the limitations of this study was nonresponse bias. For instance, it is possible that anesthesia providers who were more familiar with the study and more interested in obstetric anesthesia practice were more likely to share email contact information and complete the survey. This increased the likelihood that respondents, as a group, were different from nonrespondents, thus contributing to the nonreponse bias. Therefore, the mechanism of participating in the study has a self-selection effect and serves as a major confounder to our findings. If it were possible to measure provider-specific covariates, it might be possible to adjust for nonresponse missingness due using statistical methods, but the design of the study and logistical constraints prevented the collection of these data. Furthermore, the finding that response rates were statistically different across strata suggests that there may be systematic differences in the survey response patterns across hospital strata that might confound between-stratum comparisons.

It is possible that our change in methods from a mail-in survey to an electronic survey may have selected for more technologically savvy practitioners. Perhaps practitioners in very rural or economically disadvantaged centers may not have had Internet access to complete the survey. However, we thought that the disadvantage in this computer age of reverting to a mail-in survey is that most practitioners were more likely to respond to a relatively less time-consuming email than to a hand-written survey, therefore increasing our response rate. It is also possible that anesthesia providers are oversurveyed and time limited and feel that the survey was not a priority. Although our personal phone calls attempted to stress the importance of the information gained in this survey, a larger effort can be made with future surveys to increase the visibility and stress the utility of the information to the hospitals and anesthesia providers. This could include announcements at meetings, advertisements in journals, and informational emails sent to anesthesia providers and/or hospital administrators.

This survey was an update on current practice and staffing for obstetric anesthesia in the United States. Substantial improvements in the provision of neuraxial anesthesia for labor have been made. Anesthesia providers should be proud of recent improvements, but there is much work still to be done in the care of the parturient. Areas for future focus are increasing patient safety and decreasing the increasing the rate of maternal morbidity. Specific areas for improvement include emergency training for all staff, using hemorrhage protocols, and addressing the concern about the public health ramifications of decreasing availability of TOLAC and the ever-increasing CD rate, and the difficulties with providing anesthesia for desired postpartum tubal ligation.


Name: Andrea J. Traynor, MD.

Contribution: This author helped design the study, conduct the study, analyze the data, and write the manuscript.

Attestation: Andrea J. Traynor has seen the original study data, reviewed the analysis of the data, approved the final manuscript, and is the author responsible for archiving the study files.

Name: Meredith Aragon, BA.

Contribution: This author helped design the study, conduct the study, and write the manuscript.

Attestation: Meredith Aragon has seen the original study data, reviewed the analysis of the data, and approved the final manuscript.

Name: Debashis Ghosh, PhD.

Contribution: This author helped design the study, analyze the data, and write the manuscript.

Attestation: Debashis Ghosh has seen the original study data, reviewed the analysis of the data, and approved the final manuscript.

Name: Ray S. Choi, MD.

Contribution: This author helped design the study, conduct the study, and write the manuscript.

Attestation: Ray S. Choi has seen the original study data, reviewed the analysis of the data, and approved the final manuscript.

Name: Colleen Dingmann, RN, PhD.

Contribution: This author helped design the study, conduct the study, and write the manuscript.

Attestation: Colleen Dingmann has seen the original study data, reviewed the analysis of the data, and approved the final manuscript.

Name: Zung Vu Tran, PhD.

Contribution: This author helped design the study, analyze the data, and write the manuscript.

Attestation: Zung Vu Tran has seen the original study data, reviewed the analysis of the data, and approved the final manuscript.

Name: Brenda A. Bucklin, MD.

Contribution: This author helped design the study, conduct the study, analyze the data, and write the manuscript.

Attestation: Brenda A. Bucklin has seen the original study data, reviewed the analysis of the data, and approved the final manuscript.

This manuscript was handled by: Cynthia A. Wong, MD.


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