- Email: [email protected]
Antepartum nonobstetrical surgery at ≥23 weeks’ gestation and risk for preterm delivery
Research
ajog.org
OBSTETRICS
Antepartum nonobstetrical surgery at ‡23 weeks’ gestation and risk for preterm delivery Elizabeth A. Baldwin, MD; Kristi S. Borowski, MD; Brian C. Brost, MD; Carl H. Rose, MD OBJECTIVE: We sought to describe the influence of antepartum
nonobstetrical surgical procedures performed at viable fetal gestational ages (GAs) on incidence of preterm delivery. STUDY DESIGN: This was a retrospective case series of patients requiring nonobstetrical surgery at 23 weeks’ gestation at the Mayo Clinic during the interval 1992 through 2014. Data were abstracted for maternal demographic variables, operative procedure, anesthetic type, whether intraoperative fetal monitoring was employed, and both GA and method of delivery. RESULTS: In all, 111 patients underwent 121 operative procedures
at a mean GA of 29.2 weeks (range, 23e37 weeks). The majority of procedures were completed under general anesthesia (88/121, 73%), with intraoperative fetal monitoring performed in 14 cases (14/121, 12%); fetal loss occurred during a single unmonitored
procedure. Outcome data were available for the majority of patients (86/111, 78%) with preterm delivery occurring in 41% (35/86) at a mean GA of 36.9 weeks (range, 25e41 weeks). Mean interval from procedure to delivery was 7.7 weeks, with 9 patients (9/86, 10%) delivering within 1 week of surgery. Neither procedures requiring entry into the abdominal cavity (P ¼ .65) nor GA at time of procedure (P ¼ 1.0) statistically influenced the risk of preterm delivery. CONCLUSION: Nonobstetrical surgical procedures performed at or beyond fetal viability increased the incidence of preterm delivery regardless of surgical site or timing of procedure, however the risk of intraoperative or immediate postoperative obstetrical complications was relatively low.
Key words: antepartum surgery, fetal viability, preterm delivery
Cite this article as: Baldwin EA, Borowski KS, Brost BC, et al. Antepartum nonobstetrical surgery at ‡23 weeks’ gestation and risk for preterm delivery. Am J Obstet Gynecol 2015;212:232.e1-5.
A
ntepartum nonobstetric surgical procedures are required during approximately 1/635 pregnancies in the United States.1 As elective surgical interventions are typically performed at 14-22 weeks’ gestation, procedures at or beyond the threshold of fetal viability (23-24 weeks in most institutions) are generally reserved for urgent or emergent maternal indications. Clinical management dictates that obstetricians are often responsible for addressing concerns on the part of patients,
From the Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, Mayo Clinic, Rochester, MN. Received May 21, 2014; revised July 20, 2014; accepted Sept. 3, 2014.
families, and colleagues regarding the potential effects of surgery on pregnancy outcomes and advisability of intraoperative fetal monitoring. A PubMed search using the terms ‘nonobstetric surgery,’ ‘surgery,’ and ‘pregnancy’ from 1966 through early 2014 revealed limited data existent in the published obstetric and anesthesia literature to guide specifics of management, as reflected in the ambiguity of recommendations proposed in the 2011 American Congress of Obstetricians and Gynecologists (ACOG) committee opinion.2 From this perspective, we elected to review the Mayo Clinic experience over the past 23 years to determine pregnancy outcomes following surgical procedures performed at gestational ages (GAs) of 23 weeks.
The authors report no conflict of interest.
M ATERIALS
Corresponding author: Carl H. Rose, MD. [email protected]
The Mayo Clinic Department of Obstetrics electronic database was reviewed to identify all patients undergoing a surgical procedure within 12 months of a documented pregnancy and/or delivery
0002-9378/$36.00 ª 2015 Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.ajog.2014.09.001
AND
232.e1 American Journal of Obstetrics & Gynecology FEBRUARY 2015
M ETHODS
from January 1992 through March 2014. For study purposes, a GA of 23 weeks’ gestation was considered to represent the threshold of fetal viability in our institution. Each electronic medical record identified was reviewed to confirm an antepartum surgical procedure was performed, and then abstracted for maternal demographic variables, GA at time of surgery, and procedure and anesthetic types, with GA at delivery selected as the primary outcome. Anesthetic records were reviewed in detail for all patients in whom intraoperative fetal monitoring was performed. As modifications in anesthetic technique to address potentially compromised fetal status are difficult to objectively qualify and printed fetal heart rate tracings were not retained for review, we considered the administration of vasoactive medications to represent a surrogate marker for fetal compromise unless recorded exclusively for maternal indication. Entry into the abdominal cavity was empirically
Obstetrics
ajog.org
TABLE 1
Demographic data Demographic variable
Patients undergoing Patients undergoing nonabdominal-entry All patients abdominal-entry (n [ 111) procedures (n [ 40) procedures (n [ 71) P value
Age, y
27.6
27.3
27.8
.64 (NS)
2.5
2.4
2.6
.47 (NS)
1.0
Gravidity Parity Previous preterm deliveries, total 1 previous 2 previous
0.9
1.0
.21 (NS)
13 (11.7%)
7 (18.0%)
6 (8.0%)
.22 (NS)
11
6
5
2
1
1
All values are expressed as means. NS, nonsignificant differences between groups. Baldwin. Nonobstetrical surgery at 23 weeks’ gestation and preterm delivery. Am J Obstet Gynecol 2015.
considered to impart higher fetal risk due to potential for direct uterine manipulation or injury. Student t test was employed for comparison of population demographics and Fisher exact test utilized for comparison of outcomes between groups, with a P value of < .05 considered to represent statistical significance. This study was approved by the Mayo Clinic Institutional Review Board under protocol no. 06-002729.
R ESULTS During the 23-year study interval, approximately 36,100 patients were delivered at the Mayo Clinic in Rochester, MN. A total of 121 surgical procedures
were performed in 111 patients at 23 weeks’ gestation, for an incidence of approximately 1 procedure per 325 pregnancies. Singleton gestations comprised 108 of the 111 pregnancies, with 3 twin pregnancies included. Multiple procedures were required in 8 patients during a single pregnancy, 5 of which were performed for recurrent urologic indications. Demographics are shown in Table 1. Surgical procedures were subdivided based on peritoneal cavity entry: all procedures requiring an abdominal incision with peritoneal entry (eg, laparoscopy or laparotomy) were classified as ‘abdominal entry,’ while those procedures not involving an abdominal incision (comprised chiefly
Research
of endoscopic gastrointestinal or genitourinary procedures) were categorized as ‘nonabdominal entry’; a single transvaginal cerclage performed at 24 0/ 7 weeks was included in this group. Mean GA at time of operation was 29.2 weeks (range, 23 3/7 to 36 5/7 weeks), and the majority of procedures (88/121, 73%) were completed under a general anesthetic (Table 2). Consistent with standardization of our obstetric and anesthesiology practices over the last decade (Figure), intraoperative electronic fetal monitoring was performed in only 14 (12%) cases during the study interval: 7 abdominal, 3 urologic, 2 thoracic, and 1 each orthopedic and parathyroid procedures. Reviewing these operative notes and anesthesia records in detail, 1 patient was administered a single dose of ephedrine for hypotension following induction of general anesthesia, but there were no recorded instances during which vasoactive medications were administered specifically for fetal heart rate abnormalities. In the 5 cases of laparoscopy or laparotomy during which fetal monitoring was performed, monitoring technique was described in only 1 operative report. A single episode of fetal loss was recognized postoperatively following cardioplegia for aortic valve replacement; in this situation a patient was referred to our institution in heart failure due to valvular regurgitation and cardiomyopathy, with the pregnancy not
TABLE 2
Procedural classifications Mean procedure-to-delivery interval, wk
Procedure type
Mean EGA procedure, wk
Mean EGA delivery, wk
Incidence of preterm delivery
GI, abdominal entry, n ¼ 32
28.0 (23e36)
37.2 (24e41)
9.0
12/32 (38%)
GI, nonabdominal entry, n ¼ 10
30.9 (26e38)
35.1 (28e40)
4.4
6/10 (60%)
Gynecologic, n ¼ 4
25.5 (23e29)
36.2 (33e39)
10.7
2/4 (50%)
Orthopedic, n ¼ 7
33.4 (26e37)
39.9 (38e41)
6.2
0/7 (0%)
Renal, n ¼ 17
31.0 (23e36)
37.5 (32e41)
6.7
7/17 (41%)
Neurosurgical, n ¼ 4
27.8 (25e33)
37.1 (35e40)
9.3
2/4 (50%)
Other, n ¼ 12
27.7 (24e33)
35.1 (25e40)
7.5
7/12 (58%)
EGA, estimated gestational age; GI, gastrointestinal. Baldwin. Nonobstetrical surgery at 23 weeks’ gestation and preterm delivery. Am J Obstet Gynecol 2015.
FEBRUARY 2015 American Journal of Obstetrics & Gynecology
232.e2
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ajog.org
FIGURE
Mayo Clinic nonobstetrical surgery fetal monitoring protocol
Baldwin. Nonobstetrical surgery at 23 weeks’ gestation and preterm delivery. Am J Obstet Gynecol 2015.
disclosed preoperatively (a pregnancy test was not performed) and only discovered at the conclusion of surgery. Immediate postoperative ultrasound revealed an intrauterine demise at approximately 25 weeks’ GA, but as fetal viabilty was not verifed prior to surgery the timing of loss was not able to be ascertained with certainty. Subsequent induction of labor and transvaginal
delivery was accomplished without incident. As patients were often transferred for management of an acute surgical condition and afterward returned to their primary providers elsewhere for prenatal care and delivery, perinatal outcome data were available for only 86/111 patients (78%). The mean GA at delivery for the group was 36.9 weeks, with a cesarean
232.e3 American Journal of Obstetrics & Gynecology FEBRUARY 2015
delivery rate (combined primary and repeat) of 37% (32/86). Thirty-five patients (35/86, 41%) ultimately delivered preterm at an average GA of 33.1 weeks, and only 9 (9/86, 10%) within 1 week of the surgical procedure. We attempted to identify any unique predictive characteristics of the 9 patients who delivered within 1 week of their surgical procedure. Operative reports were reviewed in detail; 3 cases were complicated by peritonitis or intestinal necrosis and 1 by malignancy, but no specific intraoperative complications or hemodynamic instability were described. Reflective of the remainder of the cohort, general anesthesia was used for the majority of procedures (7/9, 78%) and intraoperative monitoring was recorded in 3 cases; none of the subsequent deliveries were performed due to nonreassuring intraoperative fetal status. Analysis of delivery within 7 days vs >7 days from procedure based on abdominal entry also did not show a significant association (P ¼ .29). Specific characteristics of these cases are shown in Table 3. There was no statistical difference found in the rate of preterm delivery in the group who underwent procedures requiring ‘abdominal entry’ vs patients who underwent ‘nonabdominal entry’ procedures (P ¼ .50). Further subgroup analysis was performed for patients who underwent surgery during both ‘early’ (n ¼ 52 at 23 to 29 6/7 weeks) and ‘late’ (n ¼ 34 at 30 weeks) gestational intervals; 4 patients underwent procedures during both time intervals and were analyzed according to GA at time of initial surgery. Timing of procedure did not influence risk of preterm delivery (P ¼ .82), nor did abdominal entry in either group (‘early’ group, P ¼ .26; ‘late’ group, P ¼ 1.0). All liveborn neonates survived to nursery discharge.
C OMMENT Surgical procedures performed at or beyond fetal viability pose a relatively low risk of intraoperative or immediate postoperative obstetrical complications but appear to confer an increased risk of eventual preterm delivery. Study findings included 10% of patients
Obstetrics
ajog.org
Research
TABLE 3
Patients delivering within 1 week of procedure Patient no.
EGA, wk
Surgical procedure
Indication
Anesthetic
Interval to delivery, d
Indication for delivery
Mode of delivery
1
28 1/7
Subtotal colectomy and ileostomy
Refractory inflammatory bowel disease
General
2
Preterm labor
Vaginal
2
32
Intestinal resection
Ischemic bowel
General
2
Placental abruption, preterm labor
Vaginal
3
30 1/7
Appendectomy (open)
Acute appendicitis
General
2
Preterm labor
Vaginal
4
31 4/7
Appendectomy
Acute appendicitis
General
6
Preterm labor
Cesarean
5
24 3/7
Appendectomy
Appendiceal abscess
General
0
Postoperative nonreassuring fetal status
Cesarean
6
27
Colonoscopy
Suspected bowel obstruction
IV sedation
7
Preterm labor
Cesarean
7
36 5/7
Cystoscopy with stent placement
Obstructive nephrolithiasis
General
7
Elective
Cesarean
8
27 5/7
EGD
Gastric malignancy
IV sedation
7
Deteriorating maternal clinical status
Cesarean
9
25 1/7
Aortic valve replacement
Heart failure, cardiomyopathy
General
2
Intrauterine demise
Vaginal
EGA, estimated gestational age; EGD, esophagogastroduodenoscopy; IV, intravenous. Baldwin. Nonobstetrical surgery at 23 weeks’ gestation and preterm delivery. Am J Obstet Gynecol 2015.
undergoing nonobstetric surgery delivering within 1 week and 41% <37 weeks’ gestation, with a single recorded instance of possible intraoperative fetal demise. Subgroup analysis by procedural type and GA at time of surgery did not demonstrate any significant associations. To the best of the authors’ knowledge, this is the first study to focus exclusively on surgical procedures performed at viable fetal GAs, and provides experiential clinical data that may prove useful for preoperative counseling when these scenarios are encountered. Previous case series have demonstrated similar results to our current study. A report of 5405 nonobstetrical surgical procedures performed throughout gestation found an increased frequency of preterm delivery that did not appear to correlate with either procedural type or anesthetic selection.3 A previous review of 78 patients also suggested an increased risk of preterm delivery.1 Although procedures requiring peritoneal entry were anticipated to represent higher risk, our data suggest that any type of antepartum surgical procedure appears to carry
similar implications. Additionally, stratification of results by timing of surgery demonstrated no effect on pregnancy outcome, and no specific predictive factors for delivery within 1 week of procedure were identified. At the current time no prospective trials of intraoperative fetal monitoring exist or are currently registered on the www.clinicaltrials.gov database; the existing literature is populated primarily by individual patient reports, case series, and literature reviews.4-8 ACOG has recommended that if intraoperative monitoring is planned, a qualified individual should be present to interpret the fetal heart rate pattern and an obstetrician with cesarean delivery privileges must be readily available; these conditions represent a logistical impracticality for many hospitals.2 Although the small number of patients in the present study who underwent intraoperative fetal monitoring precludes any definitive conclusions, only a single instance of possible intraoperative fetal demise occurred in a patient undergoing intentional circulatory arrest for valve
replacement, teleologically suggesting a limited practical role. Interestingly, despite limited data, a recent survey found that only 43% of physicians would recommend intraoperative monitoring.9 Inherent to the retrospective design of this study are several strengths and limitations. As surgical procedures later in pregnancy are typically restricted to those of an urgent or emergent nature, collection of a large volume of cases is intrinsically challenging. Data were abstracted from all available electronic medical records, but on a pragmatic basis was limited to patients delivering in Rochester, MN, or the surrounding Mayo Clinic Health System. Finally, excepting the few instances of immediate postoperative delivery, subclassification of preterm deliveries into either spontaneous or medically indicated was not formally addressed. As a tertiary referral center, the Mayo Clinic provides comprehensive care to patients from Olmsted County, Minnesota, and the surrounding tri-state area. Over the past 23 years, fetal compromise during nonobstetric surgical procedures
FEBRUARY 2015 American Journal of Obstetrics & Gynecology
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Obstetrics
performed at 23 weeks’ gestation was recorded in only a single case. Intraoperative fetal monitoring did not appear to substantially influence anesthetic management, and excepting the single episode of intrauterine demise of uncertain timing, no immediate major anesthetic, obstetrical, or neonatal adverse events occurred, although consistent with previous reports the preterm delivery rate for all patients was increased approximately 4-fold over baseline.1 Although it remains speculative to draw definitive conclusions from this relatively limited number of patients, the substantial increase in preterm delivery rate may be reflective of the intrinsic severity of the underlying maternal disease process and extent of required surgical procedure rather than
ajog.org any specific aspect of perioperative management. Interestingly, of the 9 patients delivering within 1 week, 7 occurred in the presence of presumed inflammatory processes, suggesting this subgroup may merit more intensive intraoperative and postoperative monitoring. REFERENCES 1. Kort B, Katz VL, Watson WJ. The effect of nonobstetric operation during pregnancy. Surg Gynecol Obstet 1993;177:371-6. 2. ACOG Committee on Obstetric Practice. Nonobstetric surgery in pregnancy. ACOG Committee opinion no. 474. Obstet Gynecol 2011;117:420. 3. Mazze RI, Källén B. Reproductive outcome after anesthesia and operation during pregnancy: a registry study of 5405 cases. Am J Obstet Gynecol 1989;161:1178.
232.e5 American Journal of Obstetrics & Gynecology FEBRUARY 2015
4. Horrigan TJ, Villarreal R, Weinstein L. Are obstetric personnel required for intraoperative fetal monitoring during nonobstetric surgery? J Perinatol 1999;19:124-6. 5. Kuczkowski KM. Nonobstetric surgery during pregnancy: what are the risks of anesthesia? Obstet Gynecol Surv 2004;59:52-6. 6. Cohen-Kerem R, Railton C, Oren D, Lishner M, Koren G. Pregnancy outcome following non-obstetric surgical intervention. Am J Surg 2005;190:467-73. 7. Kendrick JM, Woodard CB, Cross SB. Surveyed use of fetal and uterine monitoring during maternal surgery. AORN J 1995;62: 386-92. 8. Inturrisi M. Perioperative fetal heart rate assessment of fetal heart rate and uterine activity. J Obstet Gynecol Neonatal Nurs 2000;29: 331-6. 9. Kilpatrick CC, Puig C, Chohan L, Monga M, Orejuela FJ. Intraoperative fetal heart rate monitoring during nonobstetric surgery in pregnancy: a practice survey. South Med J 2010;103:212-5.
ajog.org
OBSTETRICS
Antepartum nonobstetrical surgery at ‡23 weeks’ gestation and risk for preterm delivery Elizabeth A. Baldwin, MD; Kristi S. Borowski, MD; Brian C. Brost, MD; Carl H. Rose, MD OBJECTIVE: We sought to describe the influence of antepartum
nonobstetrical surgical procedures performed at viable fetal gestational ages (GAs) on incidence of preterm delivery. STUDY DESIGN: This was a retrospective case series of patients requiring nonobstetrical surgery at 23 weeks’ gestation at the Mayo Clinic during the interval 1992 through 2014. Data were abstracted for maternal demographic variables, operative procedure, anesthetic type, whether intraoperative fetal monitoring was employed, and both GA and method of delivery. RESULTS: In all, 111 patients underwent 121 operative procedures
at a mean GA of 29.2 weeks (range, 23e37 weeks). The majority of procedures were completed under general anesthesia (88/121, 73%), with intraoperative fetal monitoring performed in 14 cases (14/121, 12%); fetal loss occurred during a single unmonitored
procedure. Outcome data were available for the majority of patients (86/111, 78%) with preterm delivery occurring in 41% (35/86) at a mean GA of 36.9 weeks (range, 25e41 weeks). Mean interval from procedure to delivery was 7.7 weeks, with 9 patients (9/86, 10%) delivering within 1 week of surgery. Neither procedures requiring entry into the abdominal cavity (P ¼ .65) nor GA at time of procedure (P ¼ 1.0) statistically influenced the risk of preterm delivery. CONCLUSION: Nonobstetrical surgical procedures performed at or beyond fetal viability increased the incidence of preterm delivery regardless of surgical site or timing of procedure, however the risk of intraoperative or immediate postoperative obstetrical complications was relatively low.
Key words: antepartum surgery, fetal viability, preterm delivery
Cite this article as: Baldwin EA, Borowski KS, Brost BC, et al. Antepartum nonobstetrical surgery at ‡23 weeks’ gestation and risk for preterm delivery. Am J Obstet Gynecol 2015;212:232.e1-5.
A
ntepartum nonobstetric surgical procedures are required during approximately 1/635 pregnancies in the United States.1 As elective surgical interventions are typically performed at 14-22 weeks’ gestation, procedures at or beyond the threshold of fetal viability (23-24 weeks in most institutions) are generally reserved for urgent or emergent maternal indications. Clinical management dictates that obstetricians are often responsible for addressing concerns on the part of patients,
From the Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, Mayo Clinic, Rochester, MN. Received May 21, 2014; revised July 20, 2014; accepted Sept. 3, 2014.
families, and colleagues regarding the potential effects of surgery on pregnancy outcomes and advisability of intraoperative fetal monitoring. A PubMed search using the terms ‘nonobstetric surgery,’ ‘surgery,’ and ‘pregnancy’ from 1966 through early 2014 revealed limited data existent in the published obstetric and anesthesia literature to guide specifics of management, as reflected in the ambiguity of recommendations proposed in the 2011 American Congress of Obstetricians and Gynecologists (ACOG) committee opinion.2 From this perspective, we elected to review the Mayo Clinic experience over the past 23 years to determine pregnancy outcomes following surgical procedures performed at gestational ages (GAs) of 23 weeks.
The authors report no conflict of interest.
M ATERIALS
Corresponding author: Carl H. Rose, MD. [email protected]
The Mayo Clinic Department of Obstetrics electronic database was reviewed to identify all patients undergoing a surgical procedure within 12 months of a documented pregnancy and/or delivery
0002-9378/$36.00 ª 2015 Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.ajog.2014.09.001
AND
232.e1 American Journal of Obstetrics & Gynecology FEBRUARY 2015
M ETHODS
from January 1992 through March 2014. For study purposes, a GA of 23 weeks’ gestation was considered to represent the threshold of fetal viability in our institution. Each electronic medical record identified was reviewed to confirm an antepartum surgical procedure was performed, and then abstracted for maternal demographic variables, GA at time of surgery, and procedure and anesthetic types, with GA at delivery selected as the primary outcome. Anesthetic records were reviewed in detail for all patients in whom intraoperative fetal monitoring was performed. As modifications in anesthetic technique to address potentially compromised fetal status are difficult to objectively qualify and printed fetal heart rate tracings were not retained for review, we considered the administration of vasoactive medications to represent a surrogate marker for fetal compromise unless recorded exclusively for maternal indication. Entry into the abdominal cavity was empirically
Obstetrics
ajog.org
TABLE 1
Demographic data Demographic variable
Patients undergoing Patients undergoing nonabdominal-entry All patients abdominal-entry (n [ 111) procedures (n [ 40) procedures (n [ 71) P value
Age, y
27.6
27.3
27.8
.64 (NS)
2.5
2.4
2.6
.47 (NS)
1.0
Gravidity Parity Previous preterm deliveries, total 1 previous 2 previous
0.9
1.0
.21 (NS)
13 (11.7%)
7 (18.0%)
6 (8.0%)
.22 (NS)
11
6
5
2
1
1
All values are expressed as means. NS, nonsignificant differences between groups. Baldwin. Nonobstetrical surgery at 23 weeks’ gestation and preterm delivery. Am J Obstet Gynecol 2015.
considered to impart higher fetal risk due to potential for direct uterine manipulation or injury. Student t test was employed for comparison of population demographics and Fisher exact test utilized for comparison of outcomes between groups, with a P value of < .05 considered to represent statistical significance. This study was approved by the Mayo Clinic Institutional Review Board under protocol no. 06-002729.
R ESULTS During the 23-year study interval, approximately 36,100 patients were delivered at the Mayo Clinic in Rochester, MN. A total of 121 surgical procedures
were performed in 111 patients at 23 weeks’ gestation, for an incidence of approximately 1 procedure per 325 pregnancies. Singleton gestations comprised 108 of the 111 pregnancies, with 3 twin pregnancies included. Multiple procedures were required in 8 patients during a single pregnancy, 5 of which were performed for recurrent urologic indications. Demographics are shown in Table 1. Surgical procedures were subdivided based on peritoneal cavity entry: all procedures requiring an abdominal incision with peritoneal entry (eg, laparoscopy or laparotomy) were classified as ‘abdominal entry,’ while those procedures not involving an abdominal incision (comprised chiefly
Research
of endoscopic gastrointestinal or genitourinary procedures) were categorized as ‘nonabdominal entry’; a single transvaginal cerclage performed at 24 0/ 7 weeks was included in this group. Mean GA at time of operation was 29.2 weeks (range, 23 3/7 to 36 5/7 weeks), and the majority of procedures (88/121, 73%) were completed under a general anesthetic (Table 2). Consistent with standardization of our obstetric and anesthesiology practices over the last decade (Figure), intraoperative electronic fetal monitoring was performed in only 14 (12%) cases during the study interval: 7 abdominal, 3 urologic, 2 thoracic, and 1 each orthopedic and parathyroid procedures. Reviewing these operative notes and anesthesia records in detail, 1 patient was administered a single dose of ephedrine for hypotension following induction of general anesthesia, but there were no recorded instances during which vasoactive medications were administered specifically for fetal heart rate abnormalities. In the 5 cases of laparoscopy or laparotomy during which fetal monitoring was performed, monitoring technique was described in only 1 operative report. A single episode of fetal loss was recognized postoperatively following cardioplegia for aortic valve replacement; in this situation a patient was referred to our institution in heart failure due to valvular regurgitation and cardiomyopathy, with the pregnancy not
TABLE 2
Procedural classifications Mean procedure-to-delivery interval, wk
Procedure type
Mean EGA procedure, wk
Mean EGA delivery, wk
Incidence of preterm delivery
GI, abdominal entry, n ¼ 32
28.0 (23e36)
37.2 (24e41)
9.0
12/32 (38%)
GI, nonabdominal entry, n ¼ 10
30.9 (26e38)
35.1 (28e40)
4.4
6/10 (60%)
Gynecologic, n ¼ 4
25.5 (23e29)
36.2 (33e39)
10.7
2/4 (50%)
Orthopedic, n ¼ 7
33.4 (26e37)
39.9 (38e41)
6.2
0/7 (0%)
Renal, n ¼ 17
31.0 (23e36)
37.5 (32e41)
6.7
7/17 (41%)
Neurosurgical, n ¼ 4
27.8 (25e33)
37.1 (35e40)
9.3
2/4 (50%)
Other, n ¼ 12
27.7 (24e33)
35.1 (25e40)
7.5
7/12 (58%)
EGA, estimated gestational age; GI, gastrointestinal. Baldwin. Nonobstetrical surgery at 23 weeks’ gestation and preterm delivery. Am J Obstet Gynecol 2015.
FEBRUARY 2015 American Journal of Obstetrics & Gynecology
232.e2
Research
Obstetrics
ajog.org
FIGURE
Mayo Clinic nonobstetrical surgery fetal monitoring protocol
Baldwin. Nonobstetrical surgery at 23 weeks’ gestation and preterm delivery. Am J Obstet Gynecol 2015.
disclosed preoperatively (a pregnancy test was not performed) and only discovered at the conclusion of surgery. Immediate postoperative ultrasound revealed an intrauterine demise at approximately 25 weeks’ GA, but as fetal viabilty was not verifed prior to surgery the timing of loss was not able to be ascertained with certainty. Subsequent induction of labor and transvaginal
delivery was accomplished without incident. As patients were often transferred for management of an acute surgical condition and afterward returned to their primary providers elsewhere for prenatal care and delivery, perinatal outcome data were available for only 86/111 patients (78%). The mean GA at delivery for the group was 36.9 weeks, with a cesarean
232.e3 American Journal of Obstetrics & Gynecology FEBRUARY 2015
delivery rate (combined primary and repeat) of 37% (32/86). Thirty-five patients (35/86, 41%) ultimately delivered preterm at an average GA of 33.1 weeks, and only 9 (9/86, 10%) within 1 week of the surgical procedure. We attempted to identify any unique predictive characteristics of the 9 patients who delivered within 1 week of their surgical procedure. Operative reports were reviewed in detail; 3 cases were complicated by peritonitis or intestinal necrosis and 1 by malignancy, but no specific intraoperative complications or hemodynamic instability were described. Reflective of the remainder of the cohort, general anesthesia was used for the majority of procedures (7/9, 78%) and intraoperative monitoring was recorded in 3 cases; none of the subsequent deliveries were performed due to nonreassuring intraoperative fetal status. Analysis of delivery within 7 days vs >7 days from procedure based on abdominal entry also did not show a significant association (P ¼ .29). Specific characteristics of these cases are shown in Table 3. There was no statistical difference found in the rate of preterm delivery in the group who underwent procedures requiring ‘abdominal entry’ vs patients who underwent ‘nonabdominal entry’ procedures (P ¼ .50). Further subgroup analysis was performed for patients who underwent surgery during both ‘early’ (n ¼ 52 at 23 to 29 6/7 weeks) and ‘late’ (n ¼ 34 at 30 weeks) gestational intervals; 4 patients underwent procedures during both time intervals and were analyzed according to GA at time of initial surgery. Timing of procedure did not influence risk of preterm delivery (P ¼ .82), nor did abdominal entry in either group (‘early’ group, P ¼ .26; ‘late’ group, P ¼ 1.0). All liveborn neonates survived to nursery discharge.
C OMMENT Surgical procedures performed at or beyond fetal viability pose a relatively low risk of intraoperative or immediate postoperative obstetrical complications but appear to confer an increased risk of eventual preterm delivery. Study findings included 10% of patients
Obstetrics
ajog.org
Research
TABLE 3
Patients delivering within 1 week of procedure Patient no.
EGA, wk
Surgical procedure
Indication
Anesthetic
Interval to delivery, d
Indication for delivery
Mode of delivery
1
28 1/7
Subtotal colectomy and ileostomy
Refractory inflammatory bowel disease
General
2
Preterm labor
Vaginal
2
32
Intestinal resection
Ischemic bowel
General
2
Placental abruption, preterm labor
Vaginal
3
30 1/7
Appendectomy (open)
Acute appendicitis
General
2
Preterm labor
Vaginal
4
31 4/7
Appendectomy
Acute appendicitis
General
6
Preterm labor
Cesarean
5
24 3/7
Appendectomy
Appendiceal abscess
General
0
Postoperative nonreassuring fetal status
Cesarean
6
27
Colonoscopy
Suspected bowel obstruction
IV sedation
7
Preterm labor
Cesarean
7
36 5/7
Cystoscopy with stent placement
Obstructive nephrolithiasis
General
7
Elective
Cesarean
8
27 5/7
EGD
Gastric malignancy
IV sedation
7
Deteriorating maternal clinical status
Cesarean
9
25 1/7
Aortic valve replacement
Heart failure, cardiomyopathy
General
2
Intrauterine demise
Vaginal
EGA, estimated gestational age; EGD, esophagogastroduodenoscopy; IV, intravenous. Baldwin. Nonobstetrical surgery at 23 weeks’ gestation and preterm delivery. Am J Obstet Gynecol 2015.
undergoing nonobstetric surgery delivering within 1 week and 41% <37 weeks’ gestation, with a single recorded instance of possible intraoperative fetal demise. Subgroup analysis by procedural type and GA at time of surgery did not demonstrate any significant associations. To the best of the authors’ knowledge, this is the first study to focus exclusively on surgical procedures performed at viable fetal GAs, and provides experiential clinical data that may prove useful for preoperative counseling when these scenarios are encountered. Previous case series have demonstrated similar results to our current study. A report of 5405 nonobstetrical surgical procedures performed throughout gestation found an increased frequency of preterm delivery that did not appear to correlate with either procedural type or anesthetic selection.3 A previous review of 78 patients also suggested an increased risk of preterm delivery.1 Although procedures requiring peritoneal entry were anticipated to represent higher risk, our data suggest that any type of antepartum surgical procedure appears to carry
similar implications. Additionally, stratification of results by timing of surgery demonstrated no effect on pregnancy outcome, and no specific predictive factors for delivery within 1 week of procedure were identified. At the current time no prospective trials of intraoperative fetal monitoring exist or are currently registered on the www.clinicaltrials.gov database; the existing literature is populated primarily by individual patient reports, case series, and literature reviews.4-8 ACOG has recommended that if intraoperative monitoring is planned, a qualified individual should be present to interpret the fetal heart rate pattern and an obstetrician with cesarean delivery privileges must be readily available; these conditions represent a logistical impracticality for many hospitals.2 Although the small number of patients in the present study who underwent intraoperative fetal monitoring precludes any definitive conclusions, only a single instance of possible intraoperative fetal demise occurred in a patient undergoing intentional circulatory arrest for valve
replacement, teleologically suggesting a limited practical role. Interestingly, despite limited data, a recent survey found that only 43% of physicians would recommend intraoperative monitoring.9 Inherent to the retrospective design of this study are several strengths and limitations. As surgical procedures later in pregnancy are typically restricted to those of an urgent or emergent nature, collection of a large volume of cases is intrinsically challenging. Data were abstracted from all available electronic medical records, but on a pragmatic basis was limited to patients delivering in Rochester, MN, or the surrounding Mayo Clinic Health System. Finally, excepting the few instances of immediate postoperative delivery, subclassification of preterm deliveries into either spontaneous or medically indicated was not formally addressed. As a tertiary referral center, the Mayo Clinic provides comprehensive care to patients from Olmsted County, Minnesota, and the surrounding tri-state area. Over the past 23 years, fetal compromise during nonobstetric surgical procedures
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performed at 23 weeks’ gestation was recorded in only a single case. Intraoperative fetal monitoring did not appear to substantially influence anesthetic management, and excepting the single episode of intrauterine demise of uncertain timing, no immediate major anesthetic, obstetrical, or neonatal adverse events occurred, although consistent with previous reports the preterm delivery rate for all patients was increased approximately 4-fold over baseline.1 Although it remains speculative to draw definitive conclusions from this relatively limited number of patients, the substantial increase in preterm delivery rate may be reflective of the intrinsic severity of the underlying maternal disease process and extent of required surgical procedure rather than
ajog.org any specific aspect of perioperative management. Interestingly, of the 9 patients delivering within 1 week, 7 occurred in the presence of presumed inflammatory processes, suggesting this subgroup may merit more intensive intraoperative and postoperative monitoring. REFERENCES 1. Kort B, Katz VL, Watson WJ. The effect of nonobstetric operation during pregnancy. Surg Gynecol Obstet 1993;177:371-6. 2. ACOG Committee on Obstetric Practice. Nonobstetric surgery in pregnancy. ACOG Committee opinion no. 474. Obstet Gynecol 2011;117:420. 3. Mazze RI, Källén B. Reproductive outcome after anesthesia and operation during pregnancy: a registry study of 5405 cases. Am J Obstet Gynecol 1989;161:1178.
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4. Horrigan TJ, Villarreal R, Weinstein L. Are obstetric personnel required for intraoperative fetal monitoring during nonobstetric surgery? J Perinatol 1999;19:124-6. 5. Kuczkowski KM. Nonobstetric surgery during pregnancy: what are the risks of anesthesia? Obstet Gynecol Surv 2004;59:52-6. 6. Cohen-Kerem R, Railton C, Oren D, Lishner M, Koren G. Pregnancy outcome following non-obstetric surgical intervention. Am J Surg 2005;190:467-73. 7. Kendrick JM, Woodard CB, Cross SB. Surveyed use of fetal and uterine monitoring during maternal surgery. AORN J 1995;62: 386-92. 8. Inturrisi M. Perioperative fetal heart rate assessment of fetal heart rate and uterine activity. J Obstet Gynecol Neonatal Nurs 2000;29: 331-6. 9. Kilpatrick CC, Puig C, Chohan L, Monga M, Orejuela FJ. Intraoperative fetal heart rate monitoring during nonobstetric surgery in pregnancy: a practice survey. South Med J 2010;103:212-5.