Emergency Department Evaluation and Management of Non-Obstetric Pathologic Abdominal Pain in the Pregnant Patient
- Nov 25th, 2019
- Marina N. Boushra
Author: Marina Boushra, MD (EM Attending Physician, Vidant Medical Center) // Reviewed by: Alex Koyfman, MD (@EMHighAK) and Brit Long, MD (@long_brit)
A 27-year-old G4P2 female at 25-weeks gestation presents to the emergency department with right upper quadrant abdominal pain. The pain began yesterday and was initially a generalized discomfort that localized to the right upper quadrant. She has associated nausea without vomiting and has had minimal appetite for the last day. Her vital signs on arrival to the emergency department are T 38.2 C, HR 125 bpm, RR 22, BP 110/70. Abdominal examination reveals localized right upper quadrant tenderness with voluntary guarding but no peritonitis.
Abdominal pain in pregnancy can be caused by both obstetric and non-obstetric diseases, some of which are exacerbated by the pregnancy state. This series evaluates obstetric and non-obstetric causes of abdominal pain in pregnancy, with the goal of highlighting atypical presenting features in this high-risk patient group. Part 1 will discuss non-obstetric causes.
An effective assessment of these patients requires knowledge and consideration of the physiologic and anatomic changes associated with pregnancy and the way they alter disease presentation. Pregnancy is associated with several physiologic changes that alter the presentation of acute disease in pregnant women. Knowledge of the effect of these changes on presentation and vital sign changes is of utmost importance, as it will aid clinicians in recognition of often subtle changes that signal decompensation in these patients. The most notable of these changes occur in the cardiovascular system. Total blood volume increases by approximately 40%, and cardiac output increases 10-30% due to increases in resting heart rate and stroke volume.1 The respiratory system is likewise affected, with a 40% increase in ventilation to meet the increased oxygen requirements that result from the increased metabolic rate of pregnancy.1 These physiologic changes are important in acute pathology because they result in poor correlation between vital sign changes and degree of hypovolemia secondary to blood loss. Because of the increased blood volume and cardiac output, pregnant women are able to compensate for a relatively longer time before becoming symptomatic of hypovolemia when compared to their non-pregnant peers.2 Mild tachycardia, tachypnea, and narrowing of the pulse pressure are the earliest signs of hypovolemic shock in pregnant women and may go unnoticed.2 Anatomic changes in pregnancy likewise alter the presentation of common disease in pregnant women. The gravid uterus may hamper assessment of the abdomen, making it difficult to palpate hernias or abdominal masses, and may hide abdominal distention that may otherwise be clinically obvious in a non-pregnant patient.1 The gravid uterus likewise alters the position of abdominal organs through displacement, causing pain in atypical locations for a disease presentation.1
A structured approach is important for the evaluation of pregnant patients presenting with acute abdominal pain. This approach should address and systematically exclude urgent and emergent etiologies of abdominal pain that are both obstetric and non-obstetric in origin. This begins with structured history taking, which includes inquiry into the presenting complaint as well as examination of current and prior obstetric, medical, surgical history, and family history. This will help stratify the patient’s risk for the development of particular disease processes. It is particularly important to inquire regarding recent trauma, as the incidence of domestic abuse increases substantially in pregnancy and the puerperium, and such history may not be volunteered by the patient.3,4 Asking the patient to describe the quality of the pain may help differentiate visceral from peritoneal symptoms. Radiation patterns may likewise be helpful in locating the affected structure. As in all patients, physical examination provides a wealth of information but should be done with the understanding that the gravid uterus may obscure certain physical findings. Placing the patient in a lateral decubitus position to displace the uterus may help to differentiate primarily uterine pain from pain caused by other abdominal pathology: if the site of tenderness of examination moves laterally with the uterus, it is most likely uterine in origin, while tenderness that remains in the same place despite uterine movement is most likely to be extra-uterine in origin.1
Non-Obstetric Causes of Acute Abdominal Pain in Pregnancy:
Acute appendicitis is the most common surgical cause of acute abdominal pain in pregnancy, affecting approximately 1 in 800-1500 in pregnancies.5,6 Though the reported incidence of appendicitis per trimester is highly variable in the literature, perforation occurs most commonly in the third trimester, likely secondary to delayed diagnosis and management from anatomic distortion caused by the gravid uterus.1,6 Early appendicitis classically presents with colicky peri-umbilical abdominal pain from visceral irritation by the inflamed appendix. The pain then migrates to the right lower quadrant at McBurney’s point and becomes sharp due to peritoneal involvement. Importantly, appendicitis often presents atypically in about 15% of pregnant patients secondary to abdominal organ displacement by the gravid uterus, resulting in pain in the right upper quadrant, which is often misattributed to biliary colic.7 Additionally, as the peritoneum is displaced from the appendix by the growing uterus, the separation of the visceral and parietal peritoneum makes localization of pain more difficult as pregnancy progresses.8 A retrocecal or pelvic appendix may present with primarily urinary or pelvic complaints.7 Associated symptoms typically include fever, nausea, vomiting, and anorexia.9 Guarding in the case of peritonitis may not occur due to loss of abdominal wall muscle elasticity in pregnancy.1,10 Even with the diagnostic challenge of atypical presentation, timely diagnosis of particular importance in pregnancy: pregnancy is associated with a 66% increased risk of perforation for surgery delayed greater than 24 hours from symptom onset, with resultant maternal and fetal complications.11 Uncomplicated appendicitis has a 4% rate of fetal demise and negligible maternal mortality. Progression to perforation increases fetal mortality to 20-35% and maternal mortality to 4%, highlighting the importance of prompt diagnosis and timely intervention in these patients.12
Appendicitis is primarily a clinical and imaging diagnosis, though laboratory workup may aid in exclusion of other abdominal pathologies and aid in diagnosis. Laboratory workup of acute appendicitis in pregnant women is the same as the general population and should include a complete blood count and a comprehensive metabolic panel with liver function tests as well as a lipase, which help to exclude other common causes of acute abdominal pain in pregnancy.1 Leukocytosis in the setting of acute appendicitis is less useful in pregnancy, as pregnancy itself is associated with elevated white blood cell counts which may reach as high as 20,000 to 30,000 in the third trimester.1,13 Urinalysis may reveal leukocytes if the inflamed appendix is in contact with the urinary tract; clinicians should be particularly careful to avoid premature closure in these cases.1
Imaging is indicated if the diagnosis is not certain. The definitive management of appendicitis is surgical intervention, which carries its own risks to both the mother and the fetus, and imaging has been shown to reduce the rate of negative appendectomies.14 While CT is typically the preferred imaging modality for suspected appendicitis, its use in pregnancy is limited due to concern for fetal radiation exposure. In pregnant patients, ultrasound is the diagnostic modality of choice for the diagnosis of appendicitis.15,16 Ultrasound may show a thickened appendix with associated peri-appendiceal fluid, but ultrasound is highly operator dependent, with a sensitivity of 60-70% and specificity of 83-96%.17 The sensitivity of ultrasound is decreased in cases of appendiceal rupture.18 If ultrasound is equivocal, MRI can be used if available and rapidly accessible, with a sensitivity of 91% and a specificity of 98%.19 In the setting of limited MRI availability, CT can be considered for the diagnosis of appendicitis in pregnancy. The definitive management of appendicitis is surgical intervention, which may be laparoscopic or open. Minimal data is available for non-surgical management with antibiotics and fluid resuscitation in pregnant patients with appendicitis.9 Patients should receive antibiotics perioperatively and should include gram-negative and anaerobic coverage. Recommended regimens include second generation cephalosporins, extended-spectrum penicillins, or carbapenems.12
Biliary disease is very common in pregnancy, owing to physiologic changes that lead to increased gallstone production. These changes include increased cholesterol secretion, supersaturation of bile, and sluggish gallbladder contraction.5 Multiparous women have approximately twice the risk of the development of biliary disease in pregnancy.20 Patients typically present with right upper quadrant abdominal pain which may radiate to the right flank or shoulder. Associated symptoms include nausea, vomiting, and fatty food intolerance.15,16 The presence of fever is concerning for the development of cholecystitis or cholangitis. Transabdominal ultrasound is the initial test of choice and has a greater than 95% sensitivity for the detection of gallstones.8,13,15
Biliary colic can be managed with analgesic and antiemetics, with definitive management–elective cholecystectomy– delayed until after delivery.12 Similarly, initial management of cholecystitis is fluid resuscitation, analgesia, and intravenous antibiotics.1,12 Urgent surgical intervention is only necessary in cases of perforation.12 In non-severe case, definitive surgical management is controversial. Medical management is preferred in the first and third trimesters, as surgical intervention during this period is associated with increased risk of miscarriage or premature labor.1 However, biliary colic recurs in approximately 50% of medically-managed patients, and gallstone disease increases the risk of readmission nearly five times.21 Thus, definitive surgical management may be preferred for certain patients, and surgical consultation in the emergency department for patients with biliary disease is indicated both for management and follow-up.
Intestinal obstruction complicates approximately 1 in 1500-3000 in pregnancies and is the third most common indication for non-obstetric laparotomy in pregnancy.5,12,22,23 About two thirds of these cases are secondary to adhesions, though other causes include intussusception, hernia, neoplasm, and appendicitis.5 Approximately one fifth of intestinal obstructions are idiopathic.1 Pregnant patients are significantly more likely to develop obstruction secondary to volvulus than their non-pregnant counterparts.22 This is most likely to occur in the second trimester due to rapid changes in uterine size.12 Bowel displacement and distortion by the gravid uterus may predispose to twisting of the bowel loops, causing obstruction.5 Attention to the patient’s past surgical history is important, as adhesions account for more than two-thirds of intestinal obstructions, and women with a history of Roux-en-Y gastric bypass at particular risk for the development of obstruction.24–26
Symptoms of intestinal obstruction are non-specific and may be dismissed as typical symptoms of pregnancy. These include cramping abdominal pain, nausea and vomiting, and constipation. The gravid uterus may obscure the abdominal distention typical of intestinal obstruction, further delaying diagnosis.12 The diagnosis should be considered in pregnant patients who have intractable nausea and vomiting.12 A plain abdominal radiograph can be utilized first, as it is associated with limited radiation and is diagnostic in approximately 82% of cases.27 If plain films are normal and suspicion for obstruction is high, contrasted CT should be obtained, given that fetal loss is approximately 25% with delayed treatment.28 Ultrasound is emerging as a valuable diagnostic tool for the diagnosis of small bowel obstruction, with a 92% sensitivity and a 96% specificity in the general population. Additionally, a small case series of two patients in the third trimester of pregnancy in whom the diagnosis of SBO by point-of-care ultrasound (POCUS) notes that the ultrasound findings typical of bowel obstruction were all visible despite the presence of the gravid uterus.29 MRI can be utilized if available, but patients with high clinical suspicion of obstruction but negative radiograph and POCUS findings should undergo CT. Initial treatment of SBO is non-surgical, with fluid resuscitations, nasogastric decompression, and NPO status being the cornerstones of early management.5 Surgical intervention is indicated if non-operative management fails.12
Peptic ulcer disease/gastroesophageal reflux/perforated viscous
Peptic ulcer disease (PUD) is uncommon in pregnancy due to the protective effect of increased prostaglandin circulation in pregnancy.30 Estimates in the literature of the incidence of PUD are variable and range between 1 in 4,000 and 1 in 23,000 pregnancies.31–33 Unlike PUD, symptoms of gastrointestinal reflux disease (GERD) are more prominent in pregnancy, resulting from increased intra-abdominal pressure and anatomic displacement of the gastroesophageal junction by the enlarging uterus as well as from relaxation of the lower esophageal sphincter in response to increased progesterone levels.1 GERD affects 40-85% of pregnant women.34 Both PUD and GERD may present with burning epigastric pain. Hemorrhage and perforation from PUD are rare in pregnancy but associated with significant maternal and fetal mortality.32,35,36 Case reports exist of survival with prompt surgical treatment. 31,34,35 Treatment of uncomplicated PUD and GERD includes proton-pump inhibitors, histamine receptor blockers, antacids, and sucralfate, all of which are safe for use in pregnancy.1 Misoprostol, a prostaglandin analogue, is contraindicated due to increased risk of preterm labor.30
Urolithiasis and nephrolithiasis affect 1 out of 200-500 pregnancies, making stone disease of the urinary tract one of the most common causes of non-obstetric abdominal pain in pregnancy.37 A variety of hormonal and mechanical factors contribute to this high rate of stone formation in pregnancy. These include increasing glomerular filtration rate (GFR), which results in increased renal delivery of calcium, oxalate, and uric acid, all substances implicated in the development of stones. Decreased ureteral peristalsis leads to lithogenic urinary stasis in response to increasing progesterone levels.38 The alkaline urine and calciuria observed in pregnancy increase the formation of calcium phosphate crystals. Finally, physiologic hydronephrosis of the right side is seen in the majority of pregnancies and occurs between 6-10 weeks of gestation. The most notable diagnostic challenge in the pregnant patient with suspected urolithiasis is distinguishing this physiologic hydronephrosis from pathologic hydronephrosis. Retrospective analysis has shown that, while right hydronephrosis is often physiologic in pregnancy, the presence of left hydronephrosis is highly predictive of urolithiasis.39 Renal ultrasound is diagnostic study of choice in pregnant patients with suspected renal colic due to its lack of radiation and widespread availability. Management of urolithiasis is similar to non-pregnant patients. Patients with controlled pain who are able to tolerate oral intake and have preserved renal function and no evidence of infection can attempt a trial of stone passage as an outpatient.38 Tamsulosin, which is often used as an adjunctive medical expulsive therapy, is a class B medication in pregnancy and was proven in a small cohort study of 28 pregnant patients to increase rates of stone expulsion without statistically significant risk to the fetus, though this trial did not have matched controls for stone size.40
Infections of the urinary tract
The hormonal and anatomic changes of pregnancy increase the risk of development of infections of the urinary tract. As with urolithiasis, the hydronephrosis and decreased ureteral peristalsis associated with pregnancy lead to urinary stasis and therefore increased risk of infection.41 Like in the non-pregnant population, Escherichia coli is the most common organism and is implicated in 70-90% of cases of urinary tract infection in pregnancy.41 Asymptomatic bacteriuria is common and should be treated in pregnant patients, as 20-30% progress to pyelonephritis.42,43 Recommended regimens for ASB and cystitis in pregnancy include oral beta-lactams, nitrofurantoin, and fosfomycin.41,44 However, up to 30% of patients will have persistent ASB following the first course of antibiotics and guidelines recommend that all patients have a repeat outpatient urine culture one week after completion of antibiotics as a test of cure. 45,46 Associated flank pain, especially if fever is present, should raise concern for pyelonephritis. If concurrent urolithiasis is suspected, an urgent ultrasound is indicated.47 Cases of pyelonephritis in pregnancy are considered complicated and should be admitted for monitoring, intravenous antibiotics, and fluid resuscitation.48 Surgical intervention may be necessary for those who develop a perinephric abscess, emphysematous pyelonephritis, or an obstructing calculus.39
Although still rare, the risk of abdominal aneurysm risk is significantly increased in pregnancy, with pregnant women having four-fold risk of abdominal aneurysms compared to the general population.49 Half of all arterial aneurysm ruptures in women of child-bearing age are associated with pregnancy.1 Splenic artery aneurysm rupture is most common, and underlying—often undiagnosed—connective tissue disease is a major risk factor.50 Uterine compression of the aorta and iliac arteries leading to increased blood flow to the splenic and splanchnic arterial contributes to the increased rate of splenic artery aneurysm development and rupture in pregnancy.50 Hormone-induced remodeling and weakening of the arterial walls is likewise contributory to the increased rate of arterial rupture in pregnancy.50 Management is balanced resuscitation with permissive hypotension to avoid clot displacement or increased bleeding.1 Open repair is often preferred to avoid the fetal radiation exposure associated with endoscopic repair.1
Deep vein thrombosis
Pregnant women are approximately five times more likely to develop deep venous thrombosis than non-pregnant women of child-bearing age.51 Embolic disease to the lungs from these deep venous thromboses is the leading cause of maternal death in industrialized nations and nulliparity and non-O blood types confer an increased risk of antenatal thrombosis 52,53 Thrombosis of the pelvic venous system is uncommon outside of pregnancy but accounts for approximately 10% of pregnancy-related DVT.54 Pelvic venous thrombosis presents with non-specific symptoms such as sharp or cramping abdominal pain, fevers, nausea and vomiting, and may easily be initially misdiagnosed as other intra-abdominal pathology, including appendicitis or gastroenteritis.54 Clinical vigilance is, therefore, paramount to making this diagnosis, and it should be high on the differential in patients with known thrombophilic disease, including lupus and factor V Leiden mutation as well as in those with prior history of thrombosis.54 Magnetic resonance venography (MRV) is the imaging modality of choice for the diagnosis of proximal deep venous thrombosis, with a sensitivity of 98% for the diagnosis. 55 Ultrasonography can also be used for diagnosis where MRV is not available but is notably poorly sensitive for the diagnosis, with a reported 42% sensitivity.55 Anticoagulation with low molecular weight heparins (LMWH) is safe in pregnancy and is not associated with adverse maternal or fetal outcomes.53 Warfarin is teratogenic and contraindicated in pregnancy.
Table 1: Causes of non-obstetric abdominal pain in pregnancy.
- Abdominal pain is a common complaint in pregnancy and abdominal pathology in pregnant patients may arise from both obstetric and non-obstetric
- Delayed diagnosis of common conditions in pregnant patients results in significant morbidity in this high-risk groupcompared to their peers.
- The principles of diagnosis and management are the same in pregnant and non-pregnant patients.
- CT is still extremely useful as a diagnostic modality in pregnancy and should not be withheld from pregnant patients if indicated. A conversation with the patient regarding the associated risk of radiation should be undertaken and shared decision making regarding how to proceed should be applied.
- An understanding of the anatomic and physiologic changes associated with pregnancy and how they affect patient presentation is paramount to timely diagnosis and management in these patients. A multi-disciplinary team-based approach to these patients can help in the diagnosis and ideal treatment of this vulnerable patient population.
- Woodhead N, Nkwam O, Caddick V, Morad S, Mylvaganam S. Surgical causes of acute abdominal pain in pregnancy. Obstet Gynaecol. 2019;21(1):27-35. doi:10.1111/tog.12536
- Pacagnella RC, Souza JP, Durocher J, et al. A Systematic Review of the Relationship between Blood Loss and Clinical Signs. Hawkins SM, ed. PLoS One. 2013;8(3):e57594. doi:10.1371/journal.pone.0057594
- Mumford EA, Liu W, Joseph H. Postpartum Domestic Violence in Homes With Young Children: The Role of Maternal and Paternal Drinking. Violence Against Women. 2018;24(2):144-162. doi:10.1177/1077801216678093
- Knight M, Tuffnell D, Kenyon S, Shakespeare J, Gray R, Kurinczuk JJ. Saving Lives, Improving Mothers’ Care Surveillance of Maternal Deaths in the UK 2011-13 and Lessons Learned to Inform Maternity Care from the UK and Ireland Confidential Enquiries into Maternal Deaths and Morbidity 2009-13 Maternal, Newborn and Infant Clinical Outcome Review Programme.; 2015. https://www.npeu.ox.ac.uk/downloads/files/mbrrace-uk/reports/MBRRACE-UK Maternal Report 2015.pdf. Accessed May 10, 2019.
- Shervington JP, Cox C. Abdominal pain in pregnancy: diagnosis, surgery and anaesthesia. Obstet Gynaecol. 2005;2(1):17-22. doi:10.1576/toag.2000.2.1.17
- Mazze RI, Källén B. Appendectomy during pregnancy: a Swedish registry study of 778 cases. Obstet Gynecol. 1991;77(6):835-840. http://www.ncbi.nlm.nih.gov/pubmed/2030853. Accessed April 22, 2019.
- Hodjati H, Kazerooni T. Location of the appendix in the gravid patient: a re-evaluation of the established concept. Int J Gynaecol Obstet. 2003;81(3):245-247. http://www.ncbi.nlm.nih.gov/pubmed/12767564. Accessed April 22, 2019.
- Parangi S, Levine D, Henry A, Isakovich N, Pories S. Surgical gastrointestinal disorders during pregnancy. Am J Surg. 2007;193(2):223-232. doi:10.1016/J.AMJSURG.2006.04.021
- Weston P, Moroz P. Appendicitis in pregnancy: how to manage and whether to deliver. Obstet Gynaecol. 2015;17(2):105-110. doi:10.1111/tog.12188
- Basaran A, Basaran M. Diagnosis of Acute Appendicitis During Pregnancy. Obstet Gynecol Surv. 2009;64(7):481-488. doi:10.1097/OGX.0b013e3181a714bf
- Tamir IL, Bongard FS, Klein SR. Acute appendicitis in the pregnant patient. Am J Surg. 1990;160(6):571-575; discussion 575-6. http://www.ncbi.nlm.nih.gov/pubmed/2252115. Accessed April 22, 2019.
- Dietrich CS, Hill CC, Hueman M. Surgical Diseases Presenting in Pregnancy. Surg Clin North Am. 2008;88(2):403-419. doi:10.1016/J.SUC.2007.12.003
- Skubic JJ, Salim A. Emergency general surgery in pregnancy. Trauma Surg Acute Care Open. 2017;2(1):e000125. doi:10.1136/tsaco-2017-000125
- Wallace CA, Petrov MS, Soybel DI, Ferzoco SJ, Ashley SW, Tavakkolizadeh A. Influence of Imaging on the Negative Appendectomy Rate in Pregnancy. J Gastrointest Surg. 2008;12(1):46-50. doi:10.1007/s11605-007-0377-7
- Bouyou J, Gaujoux S, Marcellin L, et al. Abdominal emergencies during pregnancy. J Visc Surg. 2015;152(6):S105-S115. doi:10.1016/J.JVISCSURG.2015.09.017
- Mukherjee R, Samanta S. Surgical emergencies in pregnancy in the era of modern diagnostics and treatment. Taiwan J Obstet Gynecol. 2019;58(2):177-182. doi:10.1016/J.TJOG.2019.01.001
- Williams R, Shaw J. Ultrasound scanning in the diagnosis of acute appendicitis in pregnancy. Emerg Med J. 2007;24(5):359-360. doi:10.1136/emj.2007.048488
- Poortman P, Lohle PNM, Schoemaker CMC, et al. Comparison of CT and Sonography in the Diagnosis of Acute Appendicitis: A Blinded Prospective Study. Am J Roentgenol. 2003;181(5):1355-1359. doi:10.2214/ajr.181.5.1811355
- Ho A et al. MRI OF RIGHT LOWER QUADRANT PAIN IN PREGNANCY A B C A C E B D. J Pract Med imaging Manag. 2017. www.appliedradiology.com. Accessed May 11, 2019.
- Gilat T, Konikoff F. Pregnancy and the biliary tract. Can J Gastroenterol. 2000;14 Suppl D:55D-59D. http://www.ncbi.nlm.nih.gov/pubmed/11110613. Accessed April 25, 2019.
- Lu EJ, Curet MJ, El-Sayed YY, Kirkwood KS. Medical versus surgical management of biliary tract disease in pregnancy. Am J Surg. 2004;188(6):755-759. doi:10.1016/j.amjsurg.2004.09.002
- Augustin G, Majerovic M. Non-obstetrical acute abdomen during pregnancy. Eur J Obstet Gynecol Reprod Biol. 2007;131(1):4-12. doi:10.1016/j.ejogrb.2006.07.052
- Kilpatrick CC, Monga M. Approach to the Acute Abdomen in Pregnancy. Obstet Gynecol Clin North Am. 2007;34(3):389-402. doi:10.1016/J.OGC.2007.06.002
- Vaynshtein J, Guetta O, Replyansky I. Abdominal Pain in Pregnancy. JAMA Surg. 2019;154(2):176. doi:10.1001/jamasurg.2018.3860
- Kannan U, Gupta R, Gilchrist BF, Kella VN. Laparoscopic management of an internal hernia in a pregnant woman with Roux-en-Y gastric bypass. BMJ Case Rep. 2018;2018:bcr-2017-221979. doi:10.1136/bcr-2017-221979
- Mortelmans D, Mannaerts D, Van den Broeck S, Jacquemyn Y, Hubens G. Intussusception in pregnancy after gastric bypass: a case report. Acta Chir Belg. 2016;116(6):379-382. doi:10.1080/00015458.2016.1181311
- Coleman MT, Trianfo VA, Rund DA. Nonobstetric emergencies in pregnancy: Trauma and surgical conditions. Am J Obstet Gynecol. 1997;177(3):497-502. doi:10.1016/S0002-9378(97)70135-2
- Perdue PW, Johnson HW, Stafford PW. Intestinal obstruction complicating pregnancy. Am J Surg. 1992;164(4):384-388. doi:10.1016/S0002-9610(05)80910-9
- Sherer DM, Dalloul M, Schwartzman A, et al. Point-of-care sonographic diagnosis of maternal small bowel obstruction during pregnancy. Ultrasound Obstet Gynecol. 2016;48(3):403-404. doi:10.1002/uog.15860
- Pinas-Carrillo A, Chandraharan E. Abdominal Pain in Pregnancy: A Rational Approach to Management. Vol 27.; 2017. doi:10.1016/j.ogrm.2017.01.009
- Cappell MS. Gastric and duodenal ulcers during pregnancy. Gastroenterol Clin North Am. 2003;32(1):263-308. doi:10.1016/S0889-8553(02)00063-8
- Goel B, Rani J, Huria A, Gupta P, Dalal U. Perforated duodenal ulcer -a rare cause of acute abdomen in pregnancy. J Clin Diagn Res. 2014;8(9):OD03-4. doi:10.7860/JCDR/2014/9130.4846
- Voutilainen M, Mäntynen T, Färkkilä M, Juhola M, Sipponen P. Impact of non-steroidal anti-inflammatory drug and aspirin use on the prevalence of dyspepsia and uncomplicated peptic ulcer disease. Scand J Gastroenterol. 2001;36(8):817-821. http://www.ncbi.nlm.nih.gov/pubmed/11495076. Accessed July 22, 2019.
- Ali RAR, Egan LJ. Gastroesophageal reflux disease in pregnancy. Best Pract Res Clin Gastroenterol. 2007;21(5):793-806. doi:10.1016/j.bpg.2007.05.006
- Paul M, Tew WL, Holliday RL. Perforated peptic ulcer in pregnancy with survival of mother and child: case report and review of the literature. Can J Surg. 1976;19(5):427-429. http://www.ncbi.nlm.nih.gov/pubmed/974928. Accessed June 6, 2019.
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- Maikranz P, Coe FL, Parks JH, Lindheimer MD. Nephrolithiasis and gestation. Baillieres Clin Obstet Gynaecol. 1987;1(4):909-919. http://www.ncbi.nlm.nih.gov/pubmed/3330492. Accessed May 14, 2019.
- Biyani CS, Joyce AD. Urolithiasis in pregnancy. I: pathophysiology, fetal considerations and diagnosis. BJU Int. 2002;89(8):811-818; quiz i-ii. http://www.ncbi.nlm.nih.gov/pubmed/11972502. Accessed May 14, 2019.
- N’gamba M, Lebdai S, Hasting C, et al. Acute renal colic during pregnancy: management and predictive factors. Can J Urol. 2015;22(2):7732-7738. http://www.ncbi.nlm.nih.gov/pubmed/25891338. Accessed May 14, 2019.
- Bailey G, Vaughan L, Rose C, Krambeck A. Perinatal Outcomes with Tamsulosin Therapy for Symptomatic Urolithiasis. J Urol. 2016;195(1):99-103. doi:10.1016/j.juro.2015.06.097
- Szweda H, Jóźwik M. Urinary tract infections during pregnancy – an updated overview. Dev period Med. 20(4):263-272. http://www.ncbi.nlm.nih.gov/pubmed/28216479. Accessed May 14, 2019.
- Rouse DJ, Andrews WW, Goldenberg RL, Owen J. Screening and treatment of asymptomatic bacteriuria of pregnancy to prevent pyelonephritis: a cost-effectiveness and cost-benefit analysis. Obstet Gynecol. 1995;86(1):119-123. doi:10.1016/0029-7844(95)00097-B
- Schnarr J, Smaill F. Asymptomatic bacteriuria and symptomatic urinary tract infections in pregnancy. Eur J Clin Invest. 2008;38:50-57. doi:10.1111/j.1365-2362.2008.02009.x
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- Jacobsen AF, Skjeldestad FE, Sandset PM. Incidence and risk patterns of venous thromboembolism in pregnancy and puerperium—a register-based case-control study. Am J Obstet Gynecol. 2008;198(2):233.e1-233.e7. doi:10.1016/j.ajog.2007.08.041
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- Torkzad MR, Bremme K, Hellgren M, et al. Magnetic resonance imaging and ultrasonography in diagnosis of pelvic vein thrombosis during pregnancy. Thromb Res. 2010;126(2):107-112. doi:10.1016/j.thromres.2010.05.011