Compared with women who are not pregnant, those who are pregnant have no significant difference in postoperative complications after general surgery, according to a retrospective cohort study published online May 13 in JAMA Surgery.

“Pregnancy is associated with physiologic changes in body habitus and the coagulation, cardiovascular, pulmonary, and immune systems,” write Hunter B. Moore, MD, from the Department of Surgery, School of Medicine, University of Colorado, Aurora, and colleagues. “These changes pose a diagnostic and treatment challenge to surgeons because physical examination findings and laboratory test values are different from those routinely encountered. Therefore, it might be expected that postoperative complications in pregnant patients are increased compared with those in nonpregnant patients.”
Approximately 1 in 500 pregnant women require nonobstetric surgery. Findings from previous research comparing the occurrence of adverse outcomes after such surgery in pregnant vs nonpregnant women have been conflicting. The investigators suggest this may be because of insufficient adjustment for differences between pregnant and nonpregnant women, and they used propensity matching to overcome this obstacle.

Using the American College of Surgeons’ National Surgical Quality Improvement Program participant user file from January 1, 2006, to December 31, 2011, the investigators identified pregnant surgical patients and matched them, on the basis of 63 preoperative characteristics, with nonpregnant women undergoing the same operations by general surgeons.

Before matching, the patient pool included 2764 pregnant women, of whom 50.5% had emergency general surgery, and 516,705 nonpregnant women, of whom 13.2% had emergency general surgery. Compared with nonpregnant women, pregnant women were more likely to have surgery in an inpatient setting (75.0% vs 59.7%). They were also younger, with fewer comorbidities but more abnormal laboratory test results.

Using propensity matching, the investigators identified 2539 pregnant and 2539 nonpregnant women with no meaningful differences in preoperative characteristics.

At 30 days, pregnant women and nonpregnant women had similar rates of mortality (0.4% vs 0.3%, respectively; P = .82), overall morbidity (6.6% vs 7.4%; P = .30), and 21 individual postoperative complications.

Limitations of this study include observational design, which precludes determination of causality and lack of data on fetal outcomes.

“We did not account for fetal complications in this study and would not advocate that our findings be generalized to elective surgical situations that can be postponed until after delivery,” the study authors write. “These findings support previous reports that pregnant patients who present with acute surgical diseases should undergo the procedure if delay in definitive care will lead to progression of disease.”