Surgery & Pregnancy

Epidemiology

1. about 1% of pregnant females undergo non-obstetric surgery

2. most commonly appendectomy & cholecystectomy

Diagnosis & Workup: early & accurate diagnosis begets a better prognosis

1. US: ultrasound during pregnancy is safe & effective in identifying the etiology of acute abdominal pain in many patients & should be the initial imaging test of choice

   • best initial test for most Ob/Gyn causes of abd pain (i.e., adnexal mass, ovarian torsion, placental abruption, placenta previa, uterine rupture, & fetal demise) for which it is up to 80% sensitive & 94% specific

   • also useful for many non-Ob/Gyn causes of abd pain (i.e., symptomatic cholelithiasis, appendicitis)

     • study of choice for biliary pathology, > 90% accurate

     • visualizes appendix in up to 60% of pregnancies with RLQ pain

2. CT: abdominal & pelvic CT scan may be used in emergency situations during pregnancy but should not be the initial imaging test of choice

   • consider CT only when US is non-diagnostic & MRI is unavailable or inexpedient (i.e., trauma)

   • ionizing radiation exposure to the fetus increases the risk of teratogenesis & childhood leukemia

   • cumulative dosage during pregnancy should be limited to 50-100 mGy; for example:

     • KUB: 1-3 mGy

     • IOC: 2 mGy

     • L-spine XR: 6 mGy

     • IV pyleogram: 6 mGy

     • barium enema: 7 mGy

     • CT abdomen & pelvis: 20-50 mGy

     • ERCP (w/out pelvic shielding): 20-120 mGy

   • fetal age at exposure is important, where fetal mortality is greatest when exposure occurs w/in the 1st week of conception

     • most sensitive time period for CNS teratogenesis is 10-17 weeks EGA

     • in later pregnancy, concern shifts away from teratogenesis to increasing the risk of childhood hematologic malignancy

       • background incidence is 0.2-0.3%

       • every 10 mGy increases this by 0.06%

     • > 99% of fetuses are unaffected by cumulative dosage < 20 mGy

     • risk of teratogenesis is low when dosage is < 50 mGy

     • risk of malformation is significantly increased at doses > 150 mGy

3. MRI: non-contrasted MRI can be performed at any stage of pregnancy & is preferred over CT

   • gadolinium agents cross the placenta & may cause teratogenesis

   • in non-trauma emergencies, MRI demonstrates equivalent-to-better accuracy in diagnosing vs CT or US

4. nuclear medicine: administration of radionucleotides for diagnostic studies is safe for mother & fetus

   • radiopharmaceuticals can be administered at doses that provide whole fetal exposure of < 5 mGy

5. cholangiography: IOC & ERCP expose mother & fetus to minimal radiation & may be used selectively during pregnancy, but the lower abdomen should be shielded to decrease the exposure

   • without compromising the field of view necessary for proper imaging, shield the fetus as able

   • ERCP radiation exposure can be substantially higher for long procedures, not to mention risk of bleeding & pancreatitis

   • consider EUS & choledochoscopy as able

6. diagnostic laparoscopy: in the absence of access to imaging modalities or non-diagnostic imaging, laparoscopy may be used selectively

   • accurate & timely diagnosis of abdominal conditions during pregnancy optimizes maternal & fetal outcomes

   • risks of delayed diagnosis should be weighed against the risk of possible negative laparoscopy

Therapy

1. timing

   • laparoscopy is safe during any trimester without an increased risk to the mother & fetus

   • postponing necessary operations until after parturition increases complications for both mother & fetus

2. positioning

   • 2nd-3rd trimester pregnancies should be placed in partial LLDP to minimize vena cava compression

   • decreased venous return increases maternal hypotension & decreases placental perfusion

   • 1st trimester does not require altered positioning

3. port placement

   • open & closed abdominal entry techniques are safe when performed by an experienced surgeon

   • initial port placement should be subcostal to avoid the uterus

   • port placement should be adjusted according to fundal height

4. insufflation & CO2 monitoring

   • insufflation to 10-15 mmHg is generally safe in pregnancy, but it should be adjusted according to patient physiology

   • there is theoretical concern that intraperitoneal CO2 exchange from CO2 pneumoperitoneum can have deleterious effects to the fetus

     • animal studies show conflicting findings

     • no data has shown detrimental effects to human fetuses

   • capnography during laparoscopy can serve as a surrogate to monitor fetal acidosis

5. VTE PPX

   • pregnancy is a hypercoagulable state with a 0.1-0.2% incidence of DVT

   • all patients should have pneumatic compression & early post-op ambulation

   • LMWHs & UFH are safe & should be used when indicated (i.e. Caprini score > 4)

6. gallbladder disease

   • early surgical management is the treatment of choice

   • in patients managed non-op, symptomatic cholelithiasis recurs in 92% (if 1st trimester), 64% (2nd trimester), & 44% (3rd trimester)

   • if deciding to manage non-operatively, there is no significant difference in the rates of preterm labor and spontaneous abortion if biliary disease remains uncomplicated

   • 50% of recurrent symptomatic cholelithiasis requires hospitalization because up to 23% of such patients develop acute cholecystitis, cholangitis, or gallstone pancreatitis

   • complicated gallstone disease poses a 20% risk of preterm labor & 10-60% risk of fetal loss

7. choledocholithiasis

   • cholangitis post a 10% risk of preterm labor or spontaneous abortion

   • both ERCP and laparoscopic CBD exploration are safe in pregnancy

8. laparoscopic appendectomy

   • retrospective data from 1995-2002 suggests that complicated appendicitis carries a 6% risk of fetal loss & 11% chance of preterm labor (vs 2% and 4% when uncomplicated)

   • evidence for the use of antibiotics alone for treating uncomplicated appendicitis has not been extended to pregnancy

   • lap appy is the treatment of choice for pregnant patients w/acute appendicitis

9. other conditions

   • laparoscopic adrenalectomy, nephrectomy & splenectomy are safe procedures in appropriately selected pregnant patients

   • laparoscopy is a safe & effective in gravid patients w/symptomatic ovarian cystic masses

   • observation is acceptable for all other ovarian cystic lesions provided no concerning features for malignancy

   • laparoscopy is recommended for both diagnosis & treatment of adnexal torsion

Peri-Op Monitoring

• fetal heart monitoring

  • pre-op & post-op FHR monitoring should be performed for all viable pregnancies (i.e., 22-24 weeks EGA)

• tocolytics

  • tocolytics should not be used prophylactically when undergoing surgery

  • only consider tocolytics when signs of preterm labor are present

Resources

• Pearl, Jonathan P., et al. Guidelines for the Use of Laparoscopy During Pregnancy. Society of American Gastrointestinal and Endoscopic Surgeons, May 2017.