Surgical Disease and Trauma in Pregnancy
Emily S. Wu
Nancy A. Hueppchen
GENERAL CONSIDERATIONS
One in 500 pregnant women will require nonobstetric surgery.
The goals for diagnosis and management of surgical disease during pregnancy are to provide definitive treatment and to maintain a successful pregnancy.
Diagnosis in pregnancy can be difficult due to the physiologic changes of pregnancy; presentation and symptoms may not be typical.
Always consider and discuss the potential harm to the fetus for any intervention. Similarly, always consider and discuss the potential harm to the mother if intervention is delayed.
Risks of nonobstetric surgery during pregnancy include preterm labor, preterm delivery, and fetal loss. Overall, there is a 9% risk of preterm delivery with surgery during pregnancy.
Anatomic and Physiologic Changes in Pregnancy
The gravid uterus displaces abdominal organs cephalad and brings adnexal structures into the abdomen.
Uterine compression of the inferior vena cava decreases venous return and may cause supine hypotension syndrome. Whenever possible, the pregnant patient should be placed in the left lateral decubitus position for surgery.
Increased plasma volume, decreased hematocrit, and generally lower blood pressure make acute blood loss assessment more difficult.
The hypoalbuminemia of pregnancy predisposes the patient to edema.
Diagnostic Radiology and the Pregnant Patient
Pregnancy should not impede the use of necessary imaging studies for critical diagnoses.
According to consensus statements from multiple professional organizations, the risk of malignancy, miscarriage, or major malformations is negligible in fetuses exposed to 5 rad or less. Potential effects of up to 10 rad are too subtle to be clinically detectable or distinguishable from the background risk. The risk is highest between 8 and 15 weeks’ gestation. See Table 22-1 for estimated fetal exposure from common radiologic procedures.
Iodinated radiographic contrast is rated category B in pregnancy, although it crosses the placenta and poses potential harm to the fetal thyroid, especially at 10 to 12 weeks of gestation. The American College of Obstetricians and Gynecologists recommends avoiding iodinated contrast in pregnancy; in cases where contrast imaging is required, 123I or technetium 99m (pregnancy category C) should be used in place of 131I and the newborn should have thyroid function testing in the first week of life.
TABLE 22-1 Estimated Conceptus Dose from Common Radiologic Procedures
Procedure
Typical Conceptus Dose (rad)
Number of Studies Required to Reach 5 rads
Cervical spine or extremities x-ray
<0.0001
>50,000
Chest x-ray (two views)
0.0002
25,000
Abdominal film (single view)
0.1-0.3
17-50
Small bowel study or barium enema
0.7
7
Head CT
0
Infinite
Chest CT (including PE protocol)
0.02
250
Abdominal CT
0.4
12.5
Abdomen and pelvis CT
2.5
2
CT, computed tomography; PE, pulmonary embolism.
Adapted from Wang PI, Chong ST, Kielar AZ, et al. Imaging of pregnant and lactating patients: part 1, evidence-based review and recommendations. AJR Am J Roentgenol 2012;198(4):778-784.
Contrast agents iohexol, iopamidol, iothalamate, ioversol, ioxaglate, and metrizamide do not appear to be teratogenic. In lactating women, it should be safe to continue breast-feeding, but mothers may choose to discard breast milk for 24 hours.
Gadolinium contrast may be associated with increased risk of pregnancy loss, skeletal abnormalities, and visceral abnormalities. It should be used during pregnancy with extreme caution with full discussion of its risks and benefits.
SURGICAL DISEASES IN PREGNANCY
Pregnancy should not preclude any indicated surgery, regardless of trimester.
Nonurgent surgery is ideally performed in the second trimester. Pelvic surgery during the first trimester carries increased risk of spontaneous abortion from disruption of the corpus luteum. Inadequate operative exposure and risk of preterm delivery complicate third-trimester surgery.
Elective surgery is generally postponed until after delivery.
Preoperative and postoperative fetal heart rate monitoring appropriate for gestational age is recommended.
Intraoperative considerations include the following: positioning in left lateral decubitus, avoiding uterine manipulation, optimizing maternal oxygenation, and avoiding wide variations of blood pressure.
Intraoperative fetal heart rate monitoring is not routinely recommended but may be appropriate if the fetus is viable, electronic fetal monitoring is physically possible, interventions for fetal indications are available and consent is obtained, and potential interventions for fetal distress will not jeopardize the safety of the planned surgery.
At standard concentrations, none of the anesthetic agents currently in use have been shown to have a teratogenic effect at any gestational age.
Current data do not support the routine use of tocolytic agents in the intraoperative setting.
Acute Appendicitis
Acute appendicitis is the most common surgical complication of pregnancy, occurring in 1/1,700 pregnancies. The incidence of appendicitis is not increased in pregnancy, although appendiceal perforation is more common, particularly in the third trimester. Perforation rates are 43% in pregnancy and only 4% to 19% in nonpregnant patients. This may be related to delayed diagnosis or reluctance to operate on pregnant women.
Clinical presentation includes the following: anorexia, nausea, vomiting, fever, abdominal pain, rebound tenderness, and leukocytosis with bandemia. In the second and third trimesters, the pain is more likely to be diffuse rather than localized to the right lower quadrant.
A retrocecal appendix may cause right flank or back pain.
Seventy percent of pregnant patients with appendicitis demonstrate rebound, guarding, and referred pain, although these findings are less specific in pregnancy.
Some features of appendicitis are similar to normal symptoms of pregnancy, such as leukocytosis and back pain. However, bandemia can be revealing, and careful physical examination can exclude musculoskeletal pain.
The differential diagnosis includes the following: ectopic pregnancy, pyelonephritis, acute cholecystitis, pancreatitis, pulmonary embolism, right lower lobe pneumonia, preeclampsia with liver involvement, pelvic inflammatory disease, preterm labor, abruptio placentae, degenerating myoma, round ligament pain, adnexal torsion, ovarian cyst, and chorioamnionitis. Pyelonephritis is the most common misdiagnosis.
Diagnostic evaluation with ultrasonography is most accurate in the first and second trimesters. In later gestations, positioning the patient in the left lateral decubitus position may assist in identifying the appendix. Magnetic resonance imaging or computed tomography (CT) may be necessary to visualize and evaluate the appendix.
Management
Both maternal and perinatal morbidity and mortality are increased for appendicitis in pregnancy. Surgery should not be postponed until the presentation of generalized peritonitis. Treatment is only delayed if the patient is in active labor.
For ruptured appendix with active labor, cesarean section may be appropriate. A stable, nonseptic patient with a ruptured appendix in the later stages of labor may have a vaginal delivery.
Perioperative antibiotics with a second-generation cephalosporin, extended spectrum penicillin, or triple antibiotic therapy (ampicillin, gentamicin, clindamycin) are administered in all cases and continued postoperatively until 24 to 48 hours afebrile in cases of peritonitis, perforation, or periappendiceal abscess.
Laparoscopy may be useful if the diagnosis is uncertain (e.g., with history of pelvic inflammatory disease) and especially in the first trimester. An open laparoscopic entry technique is advisable after 12 to 14 weeks’ gestation due to the increased risk of uterine perforation on entering the abdomen.
Laparotomy is indicated if suspicion for appendicitis is high, regardless of gestational age. It is also preferred for cases of rupture or generalized peritonitis.
The role of preoperative or postoperative tocolysis is not well studied and should be used only for standard obstetric indications.
Obstetric complications of appendicitis include preterm labor (10% to 20%), spontaneous abortion, and maternal mortality. For uncomplicated appendicitis, the fetal loss rate is about 5%. Perforated appendicitis increases fetal loss to 20% to 25% and carries a maternal mortality risk of up to 4%.
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