Society For Maternal-Fetal Medicine Research Articles

ACMG SUGGESTS BROADER APPLICATION FOR NONINVASIVE PRENATAL SCREENING TESTS: NIPS tests shouldn't be limited to high‐risk pregnancies

ACMG SUGGESTS BROADER APPLICATION FOR NONINVASIVE PRENATAL SCREENING TESTS: NIPS tests shouldn't be limited to high‐risk pregnancies

Defining “Term” Pregnancy

THE NATIONAL EMPHASIS ON REDUCING PRETERM BIRTH, and the increase in scheduled deliveries, has created confusion around the definition of term gestation. The concept of “term” gestation provides guidance to clinicians and influences the public’s perceptions about the optimal timing of delivery for a healthy pregnancy. Currently, a term birth is defined as a delivery that occurs neither preterm nor postterm. Because preterm is classically defined as delivery prior to 37 weeks following the onset of the last menstrual period and postterm as after 42 weeks, term has been conventionally defined as delivery between 37 and 42 weeks. The International Classification of Diseases defines term pregnancy as delivery between 37 weeks 0 days and 41 weeks 6 days. In 2005, a US National Institute of Child Health and Human Development workshop changed the designation of deliveries between 34 weeks 0 days and 36 weeks 6 days from near term to late preterm to emphasize that these infants experience morbidities and mortality similar to those of preterm infants and to highlight the adverse consequences of delivering before 37 weeks. This nomenclature acknowledged that fetal maturation is a continuum, yet the use of the label “term” for pregnancies spanning 37 weeks 0 days through 41 weeks 6 days’ gestation remained unchanged. Recent data demonstrate that maternal and neonatal adverse outcome rates are not the same across the 6-week gestational age range that constitutes term. Rather, the frequency of adverse outcomes is U-shaped, with the nadir around 39 weeks 0 days through 40 weeks 6 days’ gestation. Before the advent of more accurate methods, last menstrual period was used for pregnancy dating because women usually remembered that date but not the date of conception. With the advent of ultrasound, accurate early home pregnancy tests, assisted reproductive technologies, and home ovulation test kits, the actual timing of conception, and consequently of gestational age, is more accurately determined than in the past. Therefore, it may not be as appropriate to continue using the same broad gestational age definition of term as when dating was less accurate. To refine further the definition of term, the National Institute of Child Health and Human Development, the American Congress of Obstetricians and Gynecologists (formerly the American College of Obstetricians and Gynecologists), the American Academy of Pediatrics, the Society for Maternal-Fetal Medicine, the March of Dimes, and the World Health Organization (WHO) convened a meeting of experts and stakeholders on December 17, 2012, in Bethesda, Maryland, and this article reports recommendations from that workshop.

In Reply

Spong, Catherine Y. MD; Berghella, Vincenzo MD; Wenstrom, Katharine D. MD; Mercer, Brian M. MD; Saade, George R. MD Author Information

ACOG approves new trisomy screen for high‐risk pregnancies

ACOG approves new trisomy screen for high‐risk pregnancies

We now take an initial step to the world!

Obstetrics & Gynecology Science, the official journal of six Korean academic societies in the fields of obstetrics and gynecology, will be published in English bimonthly from January 2013. These societies are the Korean Society of Obstetrics and Gynecology, Korean Society of Maternal Fetal Medicine, Korean Society of Gynecologic Endocrinology, Korean Society of Gynecologic Endoscopy and Minimal Invasive Surgery, Korean Society of Ultrasound in Obstetrics and Gynecology, and Korean Society of Contraception and Reproductive Health. Under the initiative of the Korean Society of Obstetrics and Gynecology, the delegates of the six societies have discussed the unification of their representative journals, and concluded that the publication of a unified journal in English is an essential part of the future growth of each society. The primary goal of Obstetrics & Gynecology Science is to become a worldwide journal by publishing highly qualified articles. Concentrating the submission of articles into one journal instead of six separate journals will allow us to reduce the risk of publishing articles of low quality. In addition, we expect that the change will give foreign scholars easier access to Obstetrics & Gynecology Science because it is published in English. Previously, the six journals of the societies were published in Korean, which made it nearly impossible for non-Koreans to read the journals. Geographical distance is no longer a significant obstacle for international communication. Accordingly, academic exchanges between different countries are so vigorous, fast, and difficult to keep up with, as are exchanges in the medical field. In the meantime, the quality of clinical practice in Korea has gradually increased in proportion to Korea's economic growth. Korean researchers have frequently presented researches at international academic meetings abroad. However, as there is a paucity of Korean journals published in English, they must submit their articles to foreign journals for the purpose of international communication. Moreover, foreign scholars have difficulty in searching Korean journals and citing Korean articles due to language differences. We will make Obstetrics & Gynecology Science an open access journal and assign digital object identifiers to all published articles. We also have a plan to provide a crosscheck service for reviewers to prevent plagiarism. Publishing Obstetrics & Gynecology Science is difficult because English is not a native language for Koreans. The burden is shared by the editors and manuscript contributors. Many contributors may hesitate to submit manuscripts to Obstetrics & Gynecology Science, and prefer to submit their work to more world-renowned journals. However, we as editors, have a firm belief that the future of Obstetrics & Gynecology Science is dependent on our continuous self-sacrificing endeavor in terms of submitting articles, peer reviewing, deliberate editing, and providing tools for easy access to this journal. We also believe that the future of Obstetrics & Gynecology Science reflects the future of the six societies. We believe that it is not an unrealistic dream for Obstetrics & Gynecology Science to become an academic journal through which distinguished researchers worldwide freely communicate with each other. We expect that all members of the six societies are eager to contribute to the efforts to reach the goals of Obstetrics & Gynecology Science. Finally, we would like to extend our appreciation to the presidents of the six societies and the Chairman of the Board of the Korean Society of Obstetrics and Gynecology for their contributions to the publication of Obstetrics & Gynecology Science. We also express our appreciation to the members of the Editorial Board and reviewers of the journal for their willingness to participate in its publication.

Twin-twin transfusion syndrome

We sought to review the natural history, pathophysiology, diagnosis, and treatment options for twin-twin transfusion syndrome (TTTS). A systematic review was performed using MEDLINE database, PubMed, EMBASE, and Cochrane Library. The search was restricted to English-language articles published from 1966 through July 2012. Priority was given to articles reporting original research, in particular randomized controlled trials, although review articles and commentaries also were consulted. Abstracts of research presented at symposia and scientific conferences were not considered adequate for inclusion in this document. Evidence reports and guidelines published by organizations or institutions such as the National Institutes of Health, Agency for Health Research and Quality, American College of Obstetricians and Gynecologists, and Society for Maternal-Fetal Medicine were also reviewed, and additional studies were located by reviewing bibliographies of identified articles. Consistent with US Preventive Task Force guidelines, references were evaluated for quality based on the highest level of evidence, and recommendations were graded accordingly. TTTS is a serious condition that can complicate 8-10% of twin pregnancies with monochorionic diamniotic (MCDA) placentation. The diagnosis of TTTS requires 2 criteria: (1) the presence of a MCDA pregnancy; and (2) the presence of oligohydramnios (defined as a maximal vertical pocket of <2 cm) in one sac, and of polyhydramnios (a maximal vertical pocket of >8 cm) in the other sac. The Quintero staging system appears to be a useful tool for describing the severity of TTTS in a standardized fashion. Serial sonographic evaluation should be considered for all twins with MCDA placentation, usually beginning at around 16 weeks and continuing about every 2 weeks until delivery. Screening for congenital heart disease is warranted in all monochorionic twins, in particular those complicated by TTTS. Extensive counseling should be provided to patients with pregnancies complicated by TTTS including natural history of the disease, as well as management options and their risks and benefits. The natural history of stage I TTTS is that more than three-fourths of cases remain stable or regress without invasive intervention, with perinatal survival of about 86%. Therefore, many patients with stage I TTTS may often be managed expectantly. The natural history of advanced (eg, stage ≥III) TTTS is bleak, with a reported perinatal loss rate of 70-100%, particularly when it presents <26 weeks. Fetoscopic laser photocoagulation of placental anastomoses is considered by most experts to be the best available approach for stages II, III, and IV TTTS in continuing pregnancies at <26 weeks, but the metaanalysis data show no significant survival benefit, and the long-term neurologic outcomes in the Eurofetus trial were not different than in nonlaser-treated controls. Even laser-treated TTTS is associated with a perinatal mortality rate of 30-50%, and a 5-20% chance of long-term neurologic handicap. Steroids for fetal maturation should be considered at 24 0/7 to 33 6/7 weeks, particularly in pregnancies complicated by stage ≥III TTTS, and those undergoing invasive interventions.

Preventing the first cesarean delivery: summary of a joint Eunice Kennedy Shriver National Institute of Child Health and Human Development, Society for Maternal-Fetal Medicine, and American College of Obstetricians and Gynecologists Workshop.

With more than one third of pregnancies in the United States being delivered by cesarean and the growing knowledge of morbidities associated with repeat cesarean deliveries, the Eunice Kennedy Shriver National Institute of Child Health and Human Development, the Society for Maternal-Fetal Medicine, and the American College of Obstetricians and Gynecologists convened a workshop to address the concept of preventing the first cesarean delivery. The available information on maternal and fetal factors, labor management and induction, and nonmedical factors leading to the first cesarean delivery was reviewed as well as the implications of the first cesarean delivery on future reproductive health. Key points were identified to assist with reduction in cesarean delivery rates including that labor induction should be performed primarily for medical indication; if done for nonmedical indications, the gestational age should be at least 39 weeks or more and the cervix should be favorable, especially in the nulliparous patient. Review of the current literature demonstrates the importance of adhering to appropriate definitions for failed induction and arrest of labor progress. The diagnosis of "failed induction" should only be made after an adequate attempt. Adequate time for normal latent and active phases of the first stage, and for the second stage, should be allowed as long as the maternal and fetal conditions permit. The adequate time for each of these stages appears to be longer than traditionally estimated. Operative vaginal delivery is an acceptable birth method when indicated and can safely prevent cesarean delivery. Given the progressively declining use, it is critical that training and experience in operative vaginal delivery are facilitated and encouraged. When discussing the first cesarean delivery with a patient, counseling should include its effect on future reproductive health.

Survey of Prenatal Counselling Practices Regarding Aneuploidy Risk Modification, Invasive Diagnostic Procedure Risks, and Procedure Eligibility Criteria in Canadian Centres

ObjectiveTo explore prenatal practices related to aneuploidy screening, risk modification, and invasive diagnostic procedures across Canadian centres. MethodsWe conducted a survey of members of the Canadian Association of Genetic Counsellors, the Canadian College of Medical Genetics, and the Canadian Society of Maternal Fetal Medicine, who provide direct counselling or management of prenatal patients in Canada ResultsEighty-two of 157 respondents indicated that their centre’s definition of advanced maternal age was ≥ 35 years, with 33/157 respondents reporting an advanced maternal age definition of ≥ 40 years. The majority of respondents reported that prenatal serum screening for aneuploidy is provincially funded in their province or territory (121/147). The majority of respondents who reported that prenatal screening is not provincially funded (17/147) were from Quebec (14/17). Thirty-nine of 123 respondents reported that their centre defines increased nuchal translucency as ≥ 3.0 mm, whereas 49/123 reported a definition of ≥ 3.5mm. Sixty-four of 150 respondents reported that the aneuploidy risk provided by serum screening is modified by a soft marker likelihood ratio, whereas 46/150 respondents reported that both age-related and serum screening risks are modified. Fifty-nine of 124 respondents reported that their centre will modify aneuploidy risk after a normal ultrasound; the most commonly cited negative likelihood ratio was 0.5. The most commonly reported procedurerelated risk for chorionic villus sampling was 1/100 (123/147) and for amniocentesis was 1/200 (73/142). ConclusionThis study demonstrates inconsistencies in prenatal practices and access to screening programs across Canada. The information gained from this study will inform policy advisors developing prenatal practice guidelines at both the provincial and national levels.

Maternal-Fetal Medicine Subspecialists' Provision of Second-Trimester Termination Services

Most abortions for pregnancy complications occur in the second trimester. Little is known about whether maternal-fetal medicine subspecialists (MFMs) perform terminations for these women. We surveyed all members of Society of Maternal Fetal Medicine by e-mail or mail regarding second-trimester abortion provision. We conducted analyses of whether MFMs perform abortions, by what method, and how frequently. Our response rate was 32.4% (689/2,125). Over two-thirds of respondents perform either dilation and evacuation (D&E) or induction; 31% perform D&Es. Male gender, frequent chorionic villus sampling provision, and being trained in D&E during fellowship are associated with performing D&Es. Nonprovision of any second-trimester abortion is significantly associated with age over 50, nonacademic practice setting, and less supportive abortion attitudes (p < 0.001). A nonsignificant trend toward association between south/southeast region and nonprovision of any second-trimester abortion is seen (p = 0.09). Many MFMs include D&E and induction termination services in their practice. Supporting current D&E providers and expanding training options for MFMs may optimize care for women diagnosed with serious pregnancy complications.

Studies Examine Fetal Surgery Trade-offs, Drug Interactions, and Uterine Rupture

AS IMAGING TECHNOLOGIES MAKE it easier to identify congenital abnormalities that might be treated through fetal surgery, clinicians and parents face difficult choices about whether to pursue such innovative treatment or to plan for corrective procedures after birth. As the Agency for Healthcare Research and Quality noted earlier this year, so far there are limited data to guide such choices (http://tinyurl.com/6o7zoa3). But a study presented at the Society for Maternal Fetal Medicine’s annual meeting in Dallas in February may help fill this gap, at least for parents and clinicians considering when to perform surgery for spina bifida diagnosed in utero. Researchers concluded that carrying out corrective surgery in utero for myelomeningocele, a bulge of spinal cord that protrudes through the spine, was costeffective compared with delaying surgery until after birth, but that risks to the mother and any subsequent children require careful consideration. Otherstudiespresentedat themeeting included one that identified potential warning signs that may precede uterine rupture in patients attempting a vaginal birthaftercesareandelivery,andanother thatdocumentedpotentialmedicationinteractionsthatmayaffect themetabolism of 17-hydroxyprogesterone caproate (17-OHPC), a drug approved by the US FoodandDrugAdministration(FDA)to help prevent preterm delivery.

Current antenatal management of monoamniotic twins: a survey of maternal-fetal medicine specialists

Objective: To assess current management of monoamniotic (MA) twins by US maternal-fetal medicine providers. Methods: We conducted a mailed survey to members of the Society for Maternal-Fetal Medicine regarding fetal surveillance practices and preferred gestational age (GA) for elective delivery with respect to MA twins. Results: Responses from 837 (43%) were received with most (83.9%) recommending elective admission for inpatient monitoring, 53.5% favoring 26–28 weeks as earliest GA for admission and 75% performing intermittent fetal monitoring (of these 81% monitored 2–3 times/day). Respondents in practice less than 10 years were less likely to use outpatient management (p < 0.05). Median GA for elective delivery was 34 weeks but was higher for those who favored outpatient management, admitted >28 weeks, and were private practitioners (p < 0.05). Conclusions: Despite a paucity of evidence, most practitioners admit MA to perform daily intermittent fetal monitoring and deliver at 34 weeks. Antenatal management protocols may also influence timing of delivery. Due to their rarity, a national registry may be a better tool to analyze the outcomes of these pregnancies.

PAMUS: placenta accreta management across the United States

Objective: There is lack of consensus regarding the optimal strategy for management of abnormal placentation. We set out to determine the actual practices of providers across the United States (U.S.). Methods: This was a cross-sectional survey of maternal-fetal medicine providers in the U.S. registered with the Society for Maternal Fetal Medicine (SMFM). Questions regarding management strategies for placenta accreta were addressed by the survey. Both univariable and multivariable analyses were performed to determine if a relationship between demographic factors and management strategies exists. Results: Approximately 64% of responders were male and 62% had been in practice less than or equal to 20 years. The respondents represented all the major regions of the U.S. and the majority had performed one to five cases in the past year. The gestational age at delivery varied by both the number of years in practice and by geographic location. About 35% of providers report the use of ureteral stents and 36% of providers use internal femoral artery balloons though this varied by region. Regional differences and recent experience play a role in whether to attempt placental removal first. Though the majority of providers believe hysterectomy is the only management option for accreta, 32% of providers have attempted conservative management. Conclusions: There is wide variation in the actual practices of physicians in the U.S. with regard to management of placenta accreta.

Management of placenta accreta: a survey of Maternal-Fetal Medicine practitioners

Objective: To describe the management strategies for placenta accreta used by Maternal-Fetal Medicine practitioners. Methods: We conducted a 36-question online survey of members of the Society for Maternal-Fetal Medicine regarding management of placenta accreta, and tabulated the results. Results: We had 508 respondents. Most respondents have been in practice for >20 years (30%), at a university-affiliated institution (58.1%). In the previous 2 years, 44.6% of respondents operated on 1–3 cases of placenta accreta, with 3% having operated on greater than 10 cases. Magnetic resonance imaging (MRI) is used as a diagnostic adjunct when the suspicion for accreta is both low (43.1%) and high (68%). In asymptomatic patients with high suspicion for accreta, 15.4% of practitioners hospitalize patients antenatally, 34.5% administer corticosteroids, and 46.8% perform amniocentesis for fetal lung maturity prior to delivery, which they schedule most commonly at 36 weeks (48.4%). Equipment requested prior to delivery includes intravascular balloon catheters (35%) and ureteral stents or catheters (26.2%). With high suspicion for accreta intraoperatively, the majority proceed with hysterectomy, but 14.9% report conservative management. Conclusion: Survey respondents employ diverse approaches in the management of patients with placenta accreta. Further study may lead to consensus strategies to improve outcome in this high-risk obstetric condition.

Is She or Isn't She in Preterm Labor: Implementing Standardized Assessment

The Preterm Labor Assessment Toolkit (PLAT) is an evidence-based toolkit designed to standardize the assessment and disposition of patients presenting with the signs and symptoms of preterm labor. The toolkit uses an algorithm to evaluate status of membranes and cervical change to determine whether or not a woman is in active preterm labor. It also provides the hospital with sample order sets, nursing education and competency checklists for sterile speculum exams, and a PowerPoint presentation for use in staff education. PLAT was developed in collaboration with Sutter Medical Center, Sacramento, and a workgroup of California health professionals in response to a state-wide assessment of maternity hospitals which revealed a lack of consistent practice and protocols. It is supported by the Society for Maternal Fetal Medicine and endorsed by American College of Obstetricians and Gynecologists (ACOG) District IX/California.

31st Annual Meeting of the Society for Maternal–Fetal Medicine

The annual meeting for the Society of Maternal–Fetal Medicine (SMFM) was held in San Francisco, CA, USA, on 7–12 February 2011. With over 2000 people in attendance, the meeting presented innovative basic science, clinical and epidemiological research. Under the leadership of Joshua Copel (Yale University School of Medicine, CT, USA), President of SMFM, and Alfred Abuhamad (Eastern Virgina Medical School, VA, USA), SMFM Program Chair, the meeting encompassed a wide variety of postgraduate courses, oral and poster sessions, and round-table luncheon presentations with world-renowned speakers.

A Review of the 2008 NICHD Research Planning Workshop

In 1995 and 1996, the National Institute of Child Health and Human Development (NICHD) convened a panel of experts in electronic fetal monitoring with the goal of reaching consensus on a set of standardized, unambiguous definitions for fetal heart rate tracings. In 2008, the Eunice Kennedy Shriver NICHD, the American College of Obstetricians and Gynecologists, and the Society for Maternal-Fetal Medicine sponsored a second research planning workshop to review and clarify the 1997 definitions, to propose a standard classification system for fetal heart rate tracings, to introduce, in consensus form, key concepts of intrapartum fetal heart rate interpretation and to make recommendations for future research. This article summarizes the proposals and recommendations of the 2008 NICHD Research Planning Workshop.

Cesarean or vaginal delivery for the breech fetus at the threshold of viability: results from a maternal–fetal medicine specialists survey

Objective. To determine how United States Maternal–Fetal medicine specialists recommend delivery of a breech fetus at the threshold of viability.Methods. U.S. Society for Maternal–Fetal Medicine (SMFM) members were surveyed about; geographic location, practice type, whether they performed deliveries, definition of threshold for viability, recommendations for delivery of a breech fetus at the threshold of viability, and if the current medical–legal climate had any bearing on their decisions. Chi-Square and Fisher's Exact tests were used for analysis.Results. 510 SMFM members responded to the questionnaire. The highest percentage of respondents stated ‘23 weeks’ (31%) as the cutoff for viability, followed by ‘24 weeks’ (21%) and ‘23 weeks or 500 g’ (10%). Seventy percent recommended cesarean delivery for a breech fetus at the threshold of viability. The majority of respondents based their decision on ‘published data’ or ‘expert opinion’, however, 58.6% reported they felt current medical evidence was inadequate to support a recommendation. Fifty-three percent stated their recommendations are affected by medical–legal concerns.Conclusion. The majority of U.S. maternal fetal–medicine specialists who responded would recommend cesarean delivery for a breech fetus at the threshold of viability, despite the belief that there is inadequate evidence in the literature to support this recommendation.

Severity of prematurity risk in spontaneous and in vitro fertilization twins: does conception mode serve as a risk factor?

Because assisted reproductive technology (ART) contributes to world-wide increases in twin pregnancies, we retrospectively evaluated whether preterm twin gestations after ART are at higher risk for delivery at earlier gestational ages compared with naturally conceived twins. The evaluation of 204 dichorial twin pregnancies, 102 after natural conception and 102 after ART, matched for maternal age, demonstrated comparable severity of prematurity risk in both groups.

270: Ultrasonic alteration of the estimated date of delivery increases caesarean delivery rates among induced labors for post term pregnancy

70 ULTRASONIC ALTERATION OF THE ESTIMATED DATE OF DELIVERY INCREASES CAESAREAN DELIVERY RATES AMONG INDUCED LABORS FOR POST TERM PREGNANCY. RHONA MAHONY, ERINA SASAKI, TILOTTAMA NANDY, FIONNUALA MCAULIFFE, COLM O’HERLIHY, MICHAEL FOLEY, Department of Obstetrics, Dublin, Ireland, National Maternity Hopsital, University College Dublin, Dublin, Ireland, Society for Maternal-Fetal Medicine, Dublin, Ireland, UCD School of Medicine and Medical Science, Dublin, Ireland, UCD School of Medicine and Medical Science, Dublin 2, Ireland OBJECTIVE: To record the frequency of sonographic reassignment of the EDD and to assess the effect of this on obstetric outcome in women delivering beyond 41 weeks= gestation. STUDY DESIGN: A consecutive observational cohort study over 12 months to June 2008, of singleton cephalic nulliparas after 41 weeks= gestation (term plus 7 days). Dates were assigned following a scan performed around 20 weeks= gestation. Induction of labor was offered at 42 weeks= gestation. . RESULTS: Among 4233 primiparas ( 37 weeks), 1000, 23.6% delivered after 41 weeks= gestation. Overall the EDD was reassigned in 406 cases ( 40.6%); put back in 297 cases (29.7%) and brought forward in 109 cases (10.9%). A potential indication for alteration of the EDD pertained in 497 cases (49.7%) resulting in a reassignment in 352 cases (72%) compared with 8.5% (43 of 505) among those with certain dates. Labor was spontaneous in 594 cases (59.4%), at a rate of 10 % per day after 41 weeks= gestation and the caesarean rate (13.6%; 81 of 594) was constant. Among those whose labor was induced for post-term pregnancy, the overall caesarean delivery rate was 33.7% (126/373) and was greater among those with altered dates (36% 52/144 vs. 32.3%: 74/229) P 0.5 and highest 51 %( 21/41) when the EDD was brought forward, compared with those put back (29% 30/103; P 0.01). The onset of labor was not influenced by maternal age, BMI or birth weight. CONCLUSION: The EDD was reassigned sonographically in a relatively high proportion of all cases (40.6%) but did not affect the caesarean rate among women who labored spontaneously (13.6%). The caesarean delivery rate for induced labor (33.7%) was higher and particularly when the EDD had been altered. Caution should be exercised when planning induction of labor for uncomplicated post term pregnancy when dates have been reassigned by mid-trimester ultrasound.

Contemporary Practice Patterns and Beliefs Regarding Tocolysis Among U.S. Maternal–Fetal Medicine Specialists

To estimate maternal-fetal medicine specialists' practice patterns and perceived risks and benefits to tocolysis. We performed a mail-based survey of all Society for Maternal-Fetal Medicine (SMFM) members in the United States. Subjects were asked whether they would recommend tocolysis and what would be their first-line tocolytic in five scenarios: 1) acute preterm labor; 2) maintenance tocolysis after arrested preterm labor; 3) repeat acute preterm labor; 4) preterm premature rupture of membranes (PROM) without contractions; and 5) preterm PROM with contractions. A total of 827 (46%) SMFM members responded. Ninety-six percent, 56%, 56%, 32%, and 29% would recommend tocolysis for acute preterm labor, repeat acute preterm labor, preterm PROM with contractions, preterm PROM without contractions, and maintenance tocolysis, respectively. The most common first-line tocolytic was magnesium for acute preterm labor (45%) and repeat acute preterm labor (41%); nifedipine was the most common maintenance tocolysis (79%). Eighty percent believed tocolysis was associated with moderate or significant benefit in the setting of acute preterm labor; however, fewer than 50% responded similarly for the other four scenarios. In all five scenarios, more than 50% of respondents indicated there was minimal or no risk associated with tocolysis. Having a nonacademic practice was independently associated with the recommendation for tocolysis. Almost all maternal-fetal medicine specialists recommend tocolysis in the setting of acute preterm labor, and many recommend tocolysis for other indications. Magnesium and nifedipine are the most commonly prescribed first-line tocolytics. III.