The incidence of pelvic ring injuries1 is 34.3% per 100,000 capita.2 Women account for approximately 69.7% of these injuries, 23% of which occur in women of childbearing age.3 In this specific patient population, concern is raised about one's future reproductive capability and method of delivery. Hormonal changes in pregnancy alter the laxity and ligament mechanics essential for adaptability during gestation and later birth. The peptide hormone, relaxin, has a collagenolytic effect, resulting in pelvic girdle laxity that increases the mobility of the pubic symphysis and sacroiliac (SI) joints.4 Surgical fixation of the pelvic ring creates a theoretical risk of decreased pelvic ring mobility during vaginal birth. According to Cannada and Barr,5 pregnant women who previously sustained a pelvic ring injury are discouraged from a trial of labor from their obstetrician. This has resulted in increased cesarean rates in comparison with 31% as reported by the American College of Obstetrics and Gynecology.5

The American College of Obstetricians and Gynecologists does not clearly define their recommendations for mode of delivery after a pelvic fracture, but instead, cases were managed on a case-by-case basis with the obstetrician's preference. No studies have determined the ability of a female patient to have a vaginal delivery after undergoing pelvic fracture fixation. However, many obstetricians are generally unwilling to have their patients attempt a vaginal delivery in the setting of symphyseal or SI fixation. This concern may be an indication for implant removal in young female patients.6

The orthopaedic surgeon can serve as a resource to obstetricians and their patients with a history of pelvic fractures regarding future pregnancies. A majority of the current literature available discusses pelvic fractures sustained during pregnancy and their subsequent management for the duration of gestation, although limited information is available on the long-term consequences of high-energy pelvic ring injuries that have undergone surgical or nonsurgical treatment regarding future pregnancy and vaginal delivery.3

The goal of this systematic review was to address the following questions:

What is the overall incidence of a cesarean section in women of childbearing age after a pelvic fracture? What is the incidence of a new cesarean section in women giving birth after a pelvic fracture? What are the indications for a cesarean section after a pelvic fracture? Is there any difference in the cesarean section rates after a pelvic fracture among women who underwent surgical fixation versus those who underwent nonsurgical treatment? Methods

An exhaustive database search was performed using the National Library of Medicine database. The search included English studies published between August 1957 and March 2022. The keywords used in the search were as follows: pelvic ring fractures, pelvic fractures, pregnancy, childbirth, vaginal delivery, and cesarean delivery. The bibliography in each article was also evaluated for additional relevant articles to allow for a thorough literature review. Institutional review board approval was not required for this study.

Article Evaluation

The abstracts of articles that resulted from the literature search were evaluated and categorized according to their level of evidence based on the systematic review article by Riehl: level I: high quality and prospective randomized clinical trials; level II: lesser quality randomized controlled trials and prospective comparative studies; level III: case-control studies and retrospective comparative studies; level IV: case series; and level V: expert opinion and case reports.1

Study Selection Criteria

The criteria for identifying articles that provided data pertaining to question 1 (the incidence of a cesarean section in women of childbearing age after a pelvic fracture) consisted of data from clinical studies focused on pregnancy outcomes after pelvic ring injuries. In addition, studies in which data accordant with pregnancy outcomes after trauma could be extracted from a larger series were analyzed.

The criteria for identifying articles pertaining to question 2 (the incidence of a new cesarean section in women giving birth after a pelvic fracture) consisted of data from clinical studies focused on pregnancy outcomes after pelvic ring injuries with a clear identification of patients with a cesarean section before a pelvic injury. Studies in which data accordant with pregnancy outcomes after trauma could be extracted from a larger series were also reviewed.

The criteria for identifying articles that provided data pertaining to question 3 (indications for a cesarean section after a pelvic fracture) consisted of data from clinical studies where pregnancy was recorded in any patient after a pelvic fracture.

The criteria for identifying articles pertaining to question 4 (the difference in cesarean section rates after a pelvic fracture among women who underwent surgical fixation versus those who underwent nonsurgical treatment) consisted of data from clinical studies focused on pregnancy outcomes after pelvic ring injuries where the treatment type was specified. In addition, studies in which data accordant with pregnancy outcomes after trauma could be extracted from a larger series were investigated.

Results

The database search resulted in a total of 33 articles. Articles that referenced pelvic fractures during pregnancy or did not report cesarean delivery rates were excluded. Among the 33 articles, 13 were found to be pertinent through the review of titles and abstracts. The 13 articles available for review reported pregnancy outcomes of women with a history of a prior pelvic fracture and are summarized in Table 1.

Table 1 - Articles Used for this Study Study Title Author(s) Study Type Level of Evidence Publication Date Journal Study Summary A Nationwide Analysis of Pelvic Ring Fractures3 Buller et al Survey study Level V March 2016 Geriatric Orthopaedic Surgery and Rehabilitation This study analyzed trends of pelvic ring fractures in the United States and determined whether the incidence of pelvic ring fractures or in-hospital mortality after a pelvic ring fracture changed between 1990 and 2007 Pelvic Ring Injuries: Surgical Management and Long-Term Outcomes7 Halawi Retrospective review Level III January 2016 Journal of Clinical Orthopaedics and Trauma This retrospective review determined that the timing of definitive fixation of a pelvic fracture is dictated by hemodynamic status, associated injuries, and the experience of the operating surgeon An International Survey of Pelvic Trauma Surgeons on the Management of Pelvic Ring Injuries2 Parry et al Survey study Level V October 2021 Injury This questionnaire consisted of general questions on the acute management of pelvic ring injuries, as well as questions regarding LC-1 injuries, LC-3 injuries, APC-3 injuries, combined vertical shear injuries through the sacrum, and vertical shear injuries through the SI joint The Effect of Relaxin on the Musculoskeletal System4 Dehghan et al Systematic review Level I November 2013 Scandinavian Journal of Medicine & Science in Sports This article summarizes the effect of relaxin on the musculoskeletal system and its vital role in biological processes including metabolism, growth, and reproduction Pelvic Fractures in Women of Childbearing Age5 Cannada et al Case-control study Level III March 2010 Clinical Orthopaedics and Related Research A comparison was made between women who were treated nonsurgically and those who were treated operatively with fixation to determine whether they could deliver vaginally or whether they required a cesarean section Changes in Pelvic Alignment in a Woman Before and After Childbirth, Using Three-Dimensional Pelvic Models Based on Magnetic Resonance Imaging: A Longitudinal Observation Case Report8 Sakamoto et al Case report Level V December 2021 Radiology case reports This case report documents pelvic alignment changes by magnetic resonance imaging in a Japanese primipara female Cesarean Section Rates Following Pelvic Fracture: A Systematic Review1 Riehl Systematic review Level I October 2014 Injury This review reports that the cesarean rate for women who had a previous pelvic fracture was 47% in comparison with only 32% for women without a prior pelvic fracture as given by the National Center for Health Statistics Advances in Labor Analgesia9 Wong Systematic review Level I August 2010 International Journal of Women's Health This review summarizes labor analgesic techniques along with the effects of these on the mother and the infant Pregnancy and Delivery After Pelvic Fracture in Fertile-Aged Women: A Nationwide Population-Based Cohort Study in Finland10 Vaajala et al Retrospective review Level III March 2022 European Journal of Obstetrics, Gynecology, and Reproductive Biology The effect of pelvic fractures on subsequent pregnancy and delivery in Finland was evaluated showing that vaginal delivery was the primary mode of delivery despite the higher rate of cesarean sections among women with a previous pelvic fracture Pregnancy Outcomes After Pelvic Ring Injury11 Vallier et al Retrospective review Level IV May 2012 Journal of Orthopaedic Trauma This study concluded that fracture pattern, minor malalignment, and retained implant are not absolute indications for cesarean delivery Effect of Trauma and Pelvic Fracture on Female Genitourinary, Sexual, and Reproductive Function12 Copeland et al Retrospective review Level III February-March 1997 Journal of Orthopaedic Trauma The short-term genitourinary effects of pelvic trauma on the female patient include possible associated genitourinary tract trauma and fetal loss secondary to blunt trauma in pregnant women Hardware Removal: Indications and Expectations6 Busam et al Systematic review Level I February 2006 Journal of the American Academy of Orthopaedic Surgeons Obstetricians are generally unwilling to let their patients attempt vaginal delivery in the setting of symphyseal or SI fixation. As a result, this concern may be an indication for implant removal in young female patients Pelvic Bone Surgery and Natural Delivery: Absolute and Relative Contraindications2 Ometti et al Systematic review Level I December 2020 Lo Scalpello Journal This review determined whether women who have undergone a previous pelvic surgery can accomplish a natural delivery or whether they should have a cesarean delivery
Mode of Delivery After a Pelvic Fracture

Riehl et al conducted a systematic review of cesarean section rates in patients with prior pelvic fractures. A total of eight articles reported pregnancy outcomes with a history of a fracture before becoming pregnant. The study concluded that women with a prior pelvic fracture underwent cesarean deliveries at a greater rate than those without a prior fracture. This article does not differentiate pelvic fracture versus pelvic ring distribution. Riehl reported the number of times certain individuals for cesarean sections were used. Elective cesarean section because of a prior fracture was cited 38 times. Other indications such as breech, failure to progress, and preeclampsia were all cited at least twice. In the authors' series, 47% of women had cesarean sections, which is markedly higher than the national rate of 32% as reported by the National Center for Health Statistics.1

A nationwide retrospective study conducted in Finland evaluated pregnancy and delivery after a pelvic fracture in women of reproductive age.10 Using a national registry, this study reported an increase in rates of urgent cesarean sections at 12.7% in the fracture group versus 9.9% in the non-fracture group in a cohort of women. Elective cesarean sections were also higher in the fracture group at 11.3% versus 6.6% in the non-fracture group. In the fracture group, 88.7% (908/1,024) of patients were offered a trial of labor. Of those patients, 12.7% (115/908) underwent urgent cesarean sections compared with 9.9% (107,042/1,156,378) of the non-fracture group. This study emphasized that although there was an increase in cesarean rates after a pelvic fracture, vaginal delivery was still the most frequent mode of delivery. The authors also recognized that the diagnosis of a prior pelvic fracture may have contributed to a lower threshold of the obstetrician to convert from a trial of labor to a cesarean section. It was reported that in this cohort, there was an increased occurrence of pelvic fractures in younger women of childbearing age, possibly contributing to the increased cesarean rates.

In a Finnish retrospective cohort study, 1,054 deliveries were identified, of which 604 women were found to have a history of a prior pelvic fracture. Subgroup analysis showed no major differences between the groups regarding the type of fracture among the fracture group. The fracture group was further subdivided by fracture diagnosis: sacrum, ilium, acetabulum, pubis, multiple fractures, and undefined. No clear differentiation was found between open reduction and internal fixation (ORIF) of pelvic ring distribution and pelvic fracture. Among women with multiple pelvic fractures, the proportion of elective cesarean sections was 17.6%. Vaginal delivery was possible in 88.7% of patients who underwent surgical treatment when compared with the non-fracture group with a 93.4% of vaginal delivery. In addition, the amount of labor analgesia and modes of delivery were similar when elective cesarean sections were controlled for.9 Women in the multiple pelvic fracture group had higher rates of elective and urgent cesarean sections at 17.6%. This percentage was higher than any other reported fracture pattern. In the fracture group, there was a higher rate of preterm deliveries with a need for the neonatal intensive care unit. This study demonstrates that vaginal delivery can be the primary mode of delivery even after multiple pelvic fractures or surgical pelvic trauma.10

Vallier et al11 evaluated pregnancy outcomes in women with previous pelvic ring fractures treated both surgically and nonsurgically. Patients who sustained a pelvic ring fracture at a level I trauma center were identified though a database and contacted to complete a questionnaire. A total of 92 people responded. Of those who responded, 17 women were treated with nonsurgical management and 14 were treated surgically by fellowship-trained traumatologists.

The study group included 10 B-type and 21 C-type pelvic fractures. Anterior ring injuries were treated with transsymphyseal plating (n = 11), percutaneous retrograde ramus screw (n = 1), or external fixation (n = 3). One patient had both anterior internal fixation and adjunctive external fixation. Posterior injuries were treated with percutaneous iliosacral screws (n = 11) and ORIF of the ileum (n = 1). Two women had acetabulum fractures that were treated concurrently with ORIF through ilioinguinal exposure.

Patients who did not have a history of a prior cesarean section were analyzed separately. Pregnancies were reported in 31 of the 92 women, for a total of 54 pregnancies. The average age was 21.9 years, and the mean Injury Severity Score was 22.8 with isolated pelvic ring injuries. The mean follow-up period was 72 months. Uncomplicated vaginal deliveries were reported in 55% (16 of 29) of deliveries. From those with vaginal deliveries, 43% (6 of 14) were treated surgically for fractures. Three had undergone ORIF of their pubic symphysis with a retained transsymphyseal implant. One had a retained superior ramus screw, and four had retained iliosacral screws. Cesarean deliveries were reported in 45% (13 of 29) of women for a total of 26 deliveries. Of these 26 deliveries, three were due to patient preference, two due to failure of progress, and two due to a breech presentation and preeclampsia. For the group with no prior cesarean section, the new cesarean section rate was 44% (20 of 45). Of those with a new cesarean section, 36% (4 of 11) had retained anterior implants, with three women having transsymphyseal plates. Of note, all of the women with uncomplicated vaginal deliveries had retained pelvic implants.11 This study emphasizes increasing new cesarean rates in women after a pelvic fracture. However, the authors provided supporting evidence for successful vaginal delivery in patients with retained implants.

Copeland et al evaluated short-term genitourinary tract trauma and fetal loss secondary to blunt trauma in pregnant women. For those in the pre-injury subgroup, 60 subjects were able to carry 124 pregnancies to term. Of those 60 subjects, 14.5% of the subjects underwent a cesarean section. In the post-injury subgroup, 23 subjects were able to carry 27 pregnancies to term. Of those 23 subjects, 48% underwent a cesarean section. However, it must be noted that 4 of the 11 subjects (36%) delivering by cesarean section post-injury had a previous cesarean section pre-injury, which may have affected the decision to perform a subsequent cesarean section. In this study, Copeland et al12 did not specify indications for cesarean sections in their study group. Patients were grouped into subgroups: mild included lateral compression (LC) type 1 and anterior-posterior compression (APC) type 1; moderate defined LC type 1 and APC type 1; severe included LC type 1, APC type 1, vertical shear, and combined mechanism of injury categories. However, the authors did not specify whether the subjects had just a pelvic fracture or an ORIF of a pelvic ring disruption.

Other Effects After Injury

Cannada et al assessed long-term outcomes of pelvic fractures in women of childbearing age in a study that explored three major topics: (1) whether genitourinary and sexual dysfunction is expected in women of childbearing age with pelvic fractures regardless of the type of treatment, (2) whether functional outcomes can be related to fracture patterns and whether they were treated with surgery, and (3) whether women treated either nonsurgically or surgically with fixation sparing the pubic symphysis can deliver children vaginally.5 In a multicenter study, 66 patients completed a questionnaire survey at an average of 6 years post-trauma. The questionnaire included 18 questions with a combination of multiple-choice and free-response questions. It included inquiries about current work after injury, bowel and bladder function changes, specifics of the original injury, pregnancy outcomes since their pelvic injury, and questions pertaining to pain with sexual intercourse. In addition, a separate questionnaire was sent to obstetrician-gynecologists, which included 20 questions regarding specifics of delivery (ie, demographics, Apgar scores, mode of delivery, and indications for cesarean section) with an option for additional comments.

The average age was 27.8 years at the time of trauma, with 37% of women having had children since their pelvic injury. Stable fractures were recorded in 62% (41/66) of patients: 40 with LC type 1 injuries and one with an AP compression type 1 injury. Unstable fractures were reported in 38% (25/66) of patients: eight with LC type 2 injuries, seven with LC type 3 injuries, four with AP compression type 2 injuries, two with AP compression type 3 injuries, and four with vertical shear injuries. Nonsurgical management was reported in 26 patients with surgical treatment in 40 patients. In this cohort, 38% of women had children since their injury. A subset of five women proceeded to have two or more children after injury. From this subgroup, 25% (10/40) of patients delivered vaginally. Of those who delivered vaginally, 40% had surgical fixation of their fractures (rami screws or SI screws). A total of 16 patients had cesarean sections while only one of these patients was given a trial of labor. Four had cesarean sections because of other pregnancy complications. Of note, there was a report of one patient having a vaginal birth after a prior cesarean section.

Of the obstetrician-gynecologists who responded, 20 of the 26 disclosed having never treated a patient with a pelvic fracture. In addition, 6 of 26 women's health providers did not believe that cesarean sections were always necessary after a pelvic fracture. However, this study reports an overall increase in the cesarean section rate to 48% post-injury when compared with 14.5% pre-injury.5

Outcomes

A study by Copeland et al12 evaluated short-term genitourinary tract trauma and fetal loss secondary to blunt trauma in pregnant woman. In this study, 123 women with pelvic fractures at a level I trauma center were evaluated with an average age of 27 years (range 16 to 44). Patients were administered a questionnaire comparing pre-injury and post-injury status in pregnancy and sexual function to include reproduction, concerned fertility, miscarriage, pregnancy, and type of delivery. Sexual function questions addressed the ability to achieve physiologic arousal and orgasm, as well as the presence and location (musculoskeletal or gynecologic) of dyspareunia. The questionnaire also investigated what type of information, if any, the hospital staff gave the patient regarding resumption of sexual activity and future ability to bear children.

In the study by Copeland et al, no subjects reported an ectopic pregnancy before or after the injury. One subject reported infertility, which is defined as the failure to conceive after 1 year without birth control. As reported, there was no difference in miscarriage rates nor infertility between the groups. The difference in pre-injury and post-injury cesarean sections was highly significant (P < 0.0001). Defined as the number of term pregnancies that resulted in a cesarean section in women with no history of a prior cesarean section, the new cesarean rate increased significantly from 11% to 33% (P = 0.02).12

Discussion

Available literature discussing best practices or rates of delivery by a trial of labor or a planned cesarean section after a pelvic fracture in women of childbearing age is sparse, and the quality of available data is limited. Studying this patient population is only feasible retrospectively or by survey because a longitudinal study would need to be conducted for the duration of a woman's childbearing years.

The review of the articles ascertained the rate of cesarean sections after a pelvic fracture to be 47%, which is much higher than the 32% rate for the general population.1 Unfortunately, the reason for this notable difference is not entirely clear. The difference in rates could be attributed to pelvic deformity or surgeon/patient bias. Copeland et al reported a correlation between the initial displacement of the pelvic ring fracture and the rates of new cesarean section. They reported five subjects with an initial fracture displacement ≥5 mm resulting in an 80% new cesarean section rate compared with a new cesarean section rate of 15% with an initial fracture displacement <5 mm. This could point to a link with the severity of the initial injury factoring into clinical decisions during delivery.12

Copeland et al also reported that only 50% of the subjects were given information or recommendations regarding their future ability to bear children while 21% of subjects believed that they had been told not to have a vaginal delivery. It is possible that this point could elucidate a misconception in patient perception. Successful vaginal delivery depends on both maternal and fetal anatomy and physiology. Until the increased cesarean section rate has been explained, counseling the patient to avoid vaginal delivery is problematic.12

In addition, there is limited information detailing pelvic changes during pregnancy for patients with a retained implant or prior fixation. Most of the data present explores pelvic changes in patients without this history. A case study by Sakamoto et al8 documented pelvic alignment changes by MRI in a Japanese primipara woman with imaging at 28 weeks estimated gestational age, 39 weeks estimated gestational age, and both 4 and 72 weeks postpartum. The authors demonstrated an increased distance between the posterior superior iliac spine and the pubic symphysis during gestation, which then markedly decreased by 4 weeks postpartum. A continual decreased distance was noted between the anterior superior iliac spine, the superior pubic symphysis, and the narrowest pubic symphysis throughout the period. This case study provides pertinent information concerning pelvic changes during pregnancy. Unfortunately, these data cannot be used to estimate changes in patients with pelvic fixation. This further illuminates the necessity for additional studies on this topic.

Limitations of this study include weakness of the studies included in this review. Many of the studies were retrospective, which increases the chance that data could be unaccounted for. Not many studies in the literature address the pregnancy outcomes in women of childbearing age. Another limitation of this study is the lack of details specific to whether there was retained implants in the subgroups of patients, thus confining the available data for patients. This further limits the ability of this study to fully address the fourth research question. Current literature lacks clear descriptions of injury types, for example, pelvic fracture versus ORIF of pelvic ring disruption. This limits the application of research and generalizability for future recommendations.

Conclusion

The long-term consequences of pelvic fractures on successive pregnancy is widely unknown. This systematic review attempted to find articles to help answer four questions, as stated previously. Data pertaining to question 1 (the incidence of a cesarean section in women of childbearing age after a pelvic fracture) provided that there is a perceptible increase in the percentages of women with cesarean sections after a pelvic fracture. Riehl et al demonstrated a 15% increase in cesarean rates using data provided by the National Center for Health Statistics.1 For question 2 (the incidence of a new cesarean section in women giving birth after a pelvic fracture), the articles that were reviewed concluded that there is an observable increase in new cesarean rates as well. Prior studies cite cesarean rate increases ranging from 15% to 33%.5,11,12 At this time, there is no clear evidence to support an elective cesarean section as the sole indication after a prior pelvic fracture. Indications for a cesarean section after a pelvic fracture with or without pelvic fixation are related to insufficient width of the patient's birth canal, thus providing an answer to question 3.2 Finally, data pertaining to question 4 (the difference in cesarean section rates after a pelvic fracture among women who underwent surgical fixation versus those who underwent nonsurgical treatment) is insufficient. No studies have determined the ability of a female patient to have a vaginal delivery after undergoing pelvic fracture fixation.2 Successful vaginal delivery depends on both maternal and fetal anatomy and physiology. Until the increased cesarean section rate has been explained, counseling the patient to avoid vaginal delivery is problematic.12 However, additional studies on this topic are necessary.

References 1. Riehl JT: Caesarean section rates following pelvic fracture: A systematic review. Injury 2014;45:1516-1521. 2. Ometti M, Bettinelli G, Candiani M, Salini V: Pelvic bone surgery and natural delivery: Absolute and relative contraindications. Lo Scalpello J 2020;34:160-164. 3. Buller LT, Best MJ, Quinnan SM: A nationwide analysis of pelvic ring fractures: Incidence and trends in treatment, length of stay, and mortality. Geriatr Orthop Surg Rehabil 2016;7:9-17. 4. Dehghan F, Haerian BS, Muniandy S, Yusof A, Dragoo JL, Salleh N: The effect of relaxin on the musculoskeletal system. Scand J Med Sci Sports 2014;24:e220-e229. 5. Cannada LK, Barr J: Pelvic fractures in women of childbearing age. Clin Orthop Relat Res 2010;468:1781-1789. 6. Busam ML, Esther RJ, Obremskey WT: Hardware removal: Indications and expectations. J Am Acad Orthop Surg 2006;14:113-120. 7. Halawi MJ: Pelvic ring injuries: Surgical management and long-term outcomes. J Clin Orthop Trauma 2016;7:1-6. 8. Sakamoto A, Watanabe G, Morito T, Katayama K, Kumagai H, Gamada K: Changes in pelvic alignment in a woman before and after childbirth, using three-dimensional pelvic models based on magnetic resonance imaging: A longitudinal observation case report. Radiol Case Rep 2021;16:3955-3960. 9. Wong CA: Advances in labor analgesia. Int J Womens Health 2010;1:139-154. 10. Vaajala M, Kuitunen I, Nyrhi L, Ponkilainen V, Kekki M, Mattila VM: Pregnancy and delivery after pelvic fracture in fertile-aged women: A nationwide population-based cohort study in Finland. Eur J Obstet Gynecol Reprod Biol 2022;270:126-132. 11. Vallier HA, Cureton BA, Schubeck D: Pregnancy outcomes after pelvic ring injury. J Orthop Trauma 2012;26:302-307. 12. Copeland CE, Bosse MJ, McCarthy ML, et al.: Effect of trauma and pelvic fracture on female genitourinary, sexual, and reproductive function. J Orthop Trauma 1997;11:73-81.