Appendicitis is the most common cause of non-obstetric emergency surgery in pregnancy, affecting 1 of every 1500 pregnancies and accounting for approximately one-quarter of non-obstetric operations [1, 2, 4]. The incidence of appendicitis in pregnant women is the same as the incidence of appendicitis in nonpregnant women, with 40% of cases occurring in the second trimester [1, 2]. Appendix rupture is two to four times more common in pregnant women than nonpregnant women, often due to diagnostic delay or hesitancy to perform an operation [1, 2, 5]. A perforated appendix increases fetal mortality from 0–1.5% to 20–35% [1, 2].

Diagnosing appendicitis in pregnancy can be challenging. The clinical presentation of appendicitis during pregnancy may differ from that of nonpregnant women, especially in the third trimester when the growing uterus can displace the appendix cranially and pain may be felt in the right flank or right upper quadrant [2, 6, 7]. Computed tomography (CT) is commonly used in nonpregnant patients to diagnose appendicitis, but should be used judiciously during pregnancy. Ultrasound and magnetic resonance imaging (MRI) are alternative imaging modalities that are safe during pregnancy [1]. A sequential imaging approach may be necessary. Ultrasound is more readily available, less expensive, and easier to perform; however, if ultrasound is inconclusive, MRI without contrast may be useful to rule out appendicitis due to its higher sensitivity (33–100% for ultrasound versus 80–100% for MRI) [8–10]. In addition, MRI may also reveal alternative causes of the patient’s abdominal pain, such as ovarian masses, intra-abdominal abscess, and nephrolithiasis [11]. If MRI is inconclusive, unavailable, or impractical, CT may be performed in consultation with obstetricians, radiologists, and the patient. The risks associated with a missed diagnosis of acute appendicitis are high and generally considered to outweigh the risks of radiation to the fetus [12, 13]. A necessary diagnostic test should not be withheld from a pregnant patient out of concern for the fetus.

Appendicitis is a surgical emergency, and delayed treatment leads to increased maternal complications, including septic shock, peritonitis, and venous thromboembolism, as well as increased fetal loss [1, 2, 4]. Delaying operative intervention may also lead to increased fetal morbidity, including preterm delivery and fetal loss [14]. In remote areas where surgical services are not available, intravenous antibiotic therapy should be used as a bridge during transport to a higher level of care [15].

Increased estrogen levels during pregnancy lead to increased cholesterol formation, and higher progesterone levels during pregnancy slow movement of the gallbladder and lead to bile stasis. When combined, these lead to increased development of cholelithiasis and cholecystitis [1, 16, 17]. Symptomatic gallstone disease affects 0.05–3% of pregnancies, and cholecystitis is the second most common non-obstetric surgical complication during pregnancy, affecting approximately 0.1% of pregnancies [1, 2, 13, 16]. The signs and symptoms of gallbladder disease in pregnant women are similar to those in their nonpregnant counterparts: nausea, vomiting, fever, right upper quadrant or epigastric pain radiating to the back, and symptoms that worsen with eating [1].

Ultrasound is the diagnostic test of choice for gallstone disease and cholecystitis [1]. If concern exists for choledocholithiasis, endoscopic retrograde cholangiopancreatography (ERCP) should be performed as it is both diagnostic and therapeutic. Magnetic resonance cholangiopancreatography (MRCP) can be performed prior to ERCP; however, MRCP may miss small stones less than 6 mm [18].

Patients with symptomatic cholelithiasis or cholecystitis may be treated surgically or conservatively with hydration, antibiotics, symptom control, and delayed cholecystectomy after pregnancy is complete [1]. However, conservative treatment of symptomatic cholelithiasis leads to higher symptom recurrence rate, increases the number of emergency department (ED) visits and hospitalizations, and increases the incidence of both cholecystitis and biliary pancreatitis [2, 13, 16, 19]. Rates of spontaneous abortions vary from 0 to 12% with conservative management and 0–2% with surgical management [16, 20].

Acute pancreatitis in pregnancy is rare, affecting less than 0.05% of pregnancies, with more than 50% of cases occurring in the third trimester [1, 21]. Symptoms are similar to those in nonpregnant women: pain, nausea, vomiting, and fever [1]. Gallstone disease is the most common cause of pancreatitis in pregnancy, occurring in about two-thirds of patients, but elevated triglyceride levels may also cause pancreatitis. Rarely, preeclampsia can cause vascular change in the pancreas as well [1, 13, 21, 22].

Management of pancreatitis includes hydration, bowel rest, and analgesia, with early resumption of enteral feeding [1, 22]. Feeding should begin by the mouth after symptom resolution in mild acute pancreatitis or by nasogastric tube in severe pancreatitis. Total parental nutrition should be avoided in pregnancy, as pregnant patients are at higher risk of acquiring catheter-related infections [24]. Recurrent gallstone pancreatitis occurs in 70% of pregnant patients, compared with 20–30% of the general population; thus, surgical consultation for cholecystectomy planning should be considered during the first episode [13, 22].

Abdominal ultrasound can be used to look for a dilated common bile duct, cholelithiasis, pancreatic abscess, and pancreatic pseudocysts; MRI also provides excellent soft tissue imaging and can be used to look for complications [1]. Endoscopic ultrasound, ERCP, and MRCP can also aid in the evaluation for common bile duct stones and should be considered if symptoms of moderate to severe pancreatitis do not improve after 2–3 days of treatment [22–24].

Due to advances in diagnosis and treatment, maternal mortality from pancreatitis has decreased from 30 to 40% in the 1970s to less than 1% in the 2000s [22]. Fetal loss secondary to maternal pancreatitis has decreased significantly as well, from near 50% to less than 5%, but can be as high as 20% when acute pancreatitis occurs in the first trimester [23, 25–27].

Diverticular disease is typically a disease of elderly patients; thus it often is forgotten in the differential diagnosis of abdominal pain in pregnancy. However, there are case reports of diverticulitis with perforation as the ultimate cause of a pregnant patient’s abdominal pain [28], and incidence of diverticular disease at one facility was 1 in 600 pregnancies [5]. Symptoms of diverticulitis may mimic that of appendicitis if the condition is right sided or due to a Meckel’s diverticulitis [28, 29]. Imaging with ultrasound, MRI, or CT should be considered to help differentiate the cause of the patient’s pain [5, 28]. Treatment with antibiotics may remove the need for surgical intervention; however, if surgery is required, a laparoscopic approach is recommended [5, 29].

As many as 1 in 1500 pregnancies are complicated by bowel obstruction [1, 12, 30]. Maternal mortality is as high as 6%, but can reach 20% in the third trimester; fetal mortality can be as high as 26% [1]. Bowel obstructions can be due to adhesions, either secondary to prior surgery or pelvic inflammatory disease, intussusception, hernias, or carcinoma. Additionally, the rapidly growing uterus can cause mechanical compression of the gastrointestinal tract; thus bowel obstruction is most common in the third trimester when the uterus is at its largest [1, 12]. In pregnant patients, volvulus is a common cause of bowel obstruction, found in 25–44% of obstructed patients, unlike in the general population where the incidence is much lower (<1%) [3, 12, 30].

Symptoms of bowel obstruction are nonspecific, as many women experience abdominal distension, pain, nausea, vomiting, and constipation as part of pregnancy [3]. Diagnosis of volvulus can often be made by plain radiograph, with a characteristic horseshoe-shaped distended bowel loop seen in 80–90% of cases. In other cases, ultrasound, MRI, colonoscopy, or even CT may be required to make the diagnosis [3, 30, 31]. Bowel obstruction may respond to conservative therapy (bowel rest, nasogastric suction, fluid and electrolyte replacement), but many cases require operative intervention, especially if signs of bowel necrosis, perforation, or peritonitis are present [3, 12, 30, 32, 33]. Occasionally, endoscopy or flexible sigmoidoscopy can successfully reduce a volvulus, allowing for operative intervention after completion of pregnancy [34, 35].

Inflammatory bowel disease (IBD) encompasses both ulcerative colitis (UC) and Crohn’s disease (CD). If the disease is inactive at conception, approximately one-third of patients experience a relapse during pregnancy, most often during the first trimester or immediate postpartum period. If conception occurs during active disease, disease activity persists or worsens in two-thirds of patients [5, 36]. Disease activity at conception and throughout pregnancy is associated with higher rates of spontaneous abortion, preterm delivery, and low birth weight infants [37–39]. Pregnancy complications, including preeclampsia, preterm premature rupture of membranes, and venous thromboembolism, are higher in patients with IBD [39].

Symptoms of IBD flares include abdominal pain, diarrhea, rectal bleeding, and weight loss. Evaluation is similar to that of nonpregnant patients; however, laboratory testing should include testing stool for Clostridium difficile, as this is more common in pregnancy [40]. If imaging studies are necessary, MRI without contrast is preferred to CT scanning, to limit radiation exposure to the fetus. Flexible sigmoidoscopy and colonoscopy can also be used to investigate disease severity [40, 41].

Treatment of IBD typically involves a combination of aminosalicylates, corticosteroids or other immune suppressants, and antibiotics [5]. The aminosalicylates, sulfasalazine, and mesalazine are considered safe to use in pregnancy, though women should receive 2 mg of daily folic acid supplementation to prevent folate deficiency [5, 37, 39, 41, 42]. In animal studies, corticosteroids have led to a higher rate of spontaneous abortions, low birth weight, and cleft palate; however, these studies have not been validated in humans [5, 37, 40, 42]. Corticosteroid use is associated with gestational diabetes, low birth weight, and preterm birth [39]. Thus, corticosteroids should be used at the lowest effective dose and for the shortest duration possible [5, 37, 39, 40]. The decision to use azathioprine, 6-mercaptopurine, infliximab, and cyclosporine, though generally considered to be safe in pregnancy, should be made in consultation with both gastroenterology and obstetrics colleagues [5, 37, 38, 40]. The use of methotrexate is contraindicated in pregnancy, as it is a known teratogen [5, 37, 39–42]. Metronidazole and quinolones are the antibiotics used most commonly to treat flares of IBD in nonpregnant patients. Some human studies have shown increased rates of cleft lip and cleft palate with the use of metronidazole; thus, its use should be avoided in the first trimester [39–42]. Most authors agree that quinolones should be avoided during pregnancy due to cartilage toxicity shown in animal studies, though no harm has been shown in human case reports [5, 37, 39–42]. Macrolide antibiotics and amoxicillin-clavulanic acid can be used as alternatives [5, 39, 40].

Pregnant women with Crohn’s disease may be at higher risk of surgical complications of CD than nonpregnant women with CD, particularly anorectal abscesses and intestinal-genitourinary fistulas [36]. Indications for surgery in IBD include severe bleeding, disease refractory to medical management, perforation, obstruction, and abscess [39, 40, 42]. Surgical intervention for IBD during pregnancy has led to increased rates of spontaneous abortion and stillbirth [5].

Gastroesophageal reflux disease (GERD) affects 30–85% of women during pregnancy, and symptoms typically worsen during pregnancy for those women already diagnosed with GERD [37, 43, 44]. The growing uterus increases intra-abdominal pressure, and increased estrogen and progesterone levels during pregnancy lead to lower esophageal sphincter relaxation and decreased gastrointestinal motility. Symptoms include heartburn, nausea, vomiting, regurgitation, epigastric pain, anorexia, dysphagia, water brash, chronic cough, and sore throat [43, 44]. Symptoms may worsen after meals or when lying flat [37, 43].

Treatment begins with diet and lifestyle modifications; however, if these are not successful, antacids and sucralfate are safe to use in pregnancy [37, 43, 44]. Histamine type 2 receptor antagonists are likely safe in pregnancy, but proton pump inhibitors should be used only in refractory cases, as some animal studies have shown teratogenic effects [37, 43–45], The pro-motility agent metoclopramide is safe in pregnancy and can improve GERD symptoms by promoting gastric emptying and increasing lower esophageal sphincter pressure [44].

Ulcer development and perforation can occur during pregnancy, though perforation is rare [45]. Ulcer perforation causes acute severe abdominal pain, nausea, and vomiting. Peritoneal signs such as guarding, rebound, and tense abdominal wall should prompt surgical evaluation [45, 46].

Constipation is a common complaint during pregnancy, affecting as many as 40% of women [5, 44, 47]. Patients present with abdominal pain, bloating, and occasionally with blood in the stool after straining [44]. Causes include increased levels of estrogen and progesterone which increase bowel transit time, mechanical blockage from the growing uterus, decreased level of maternal activity, as well as iron supplementation common during pregnancy [5, 43, 44].

Treatment focuses on patient education, with the goal of increasing dietary water and fiber intake and maternal exercise. Bulking agents and probiotics may also be helpful, and stool softeners are safe to use in pregnancy [5, 43, 44, 48, 49]. Osmotic and stimulant laxatives such as sorbitol can be used when other measures fail but can lead to electrolyte disturbances, so should only be used for short duration [5, 43, 44]. Mineral oil, castor oil, and saline hyperosmotic agents should be avoided in pregnancy, as they may lead to neonatal hypoprothrombinemia and hemorrhage, uterine contractions, and maternal fluid retention, respectively [44].

Pregnancy is a risk factor for ovarian torsion, though torsion occurs rarely affecting 1 in 5000 pregnancies [50, 51]. Torsion may involve the ovary, fallopian tube, or both [52]. It is caused by partial or complete twisting of the vascular pedicle, which leads to venous, arterial, and lymphatic obstruction that can ultimately result in ovarian necrosis [52]. When ovarian torsion occurs during pregnancy, it usually occurs in the first trimester—this is most likely due to the higher incidence of functional cysts during this period [50, 51]. Ovarian torsion is more common on the right side due to the longer right ovarian ligament, which results in increased mobility of the right ovary. The presence of the sigmoid colon in the left adnexa decreases the mobility of the left ovary [50, 51]. In addition to pregnancy, risk factors for ovarian torsion include increased ovarian size, ovarian tumors, and ovarian hyperstimulation. Assisted reproductive treatments and ovarian hyperstimulation may increase the size of ovaries and subsequently increase the chance of adnexal torsion [50]. The incidence of ovarian torsion rises to 6% after ovarian stimulation and up to 16% in cases of ovarian hyperstimulation syndrome [51]. An ovarian mass 6–8 cm is most likely to undergo torsion [50].

The most common symptom of ovarian torsion is lower abdominal pain [52, 53]. Other presenting signs and symptoms include nausea, vomiting, fever, adnexal mass, and leukocytosis [50, 51, 53]. These symptoms are nonspecific which can lead to misdiagnosis, delayed treatment, and complications such as loss of a fallopian tube or ovary [51, 53]. Pelvic ultrasound with Doppler is the imaging modality of choice, and the most common finding is an enlarged ovary or an echoic adnexal mass [50, 52–54]. The absence of arterial and venous blood flow has a 94% positive predictive value for ovarian torsion and is predictive of a nonviable ovary [52, 54]. Pelvic ultrasound with Doppler flow, however, has a high false-negative rate for ovarian torsion because of the dual blood supply from the ovarian artery and the utero-ovarian vessels [54]. The presence of blood flow on Doppler ultrasound does not rule out ovarian torsion. Early diagnosis and prompt surgical intervention are critical in order to preserve the pregnancy and the patient’s fertility [50, 53]. Laparoscopic surgery in early pregnancy has been shown to be safe for the fetus and is preferable to laparotomy [50, 51]. Delay in surgery may lead to serious infection and jeopardize the lives of both the fetus and mother [50].

The incidence of adnexal masses during pregnancy ranges between 0.2 and 2% [55, 56]. The majority of adnexal masses are found incidentally during first trimester ultrasound, but 1–2% become symptomatic during the first trimester and can develop complications that require surgical intervention [55]. The most common adnexal masses during pregnancy are functional cysts, such as follicular cysts and corpus luteal cysts, which are hormonally influenced [56, 57]. Functional cysts typically resolve spontaneously after the first 14–16 weeks of gestation. Other causes of adnexal mass during pregnancy include dermoid cysts, serous and mucinous cystadenomas, and endometriomas, which are all benign tumors [55, 56].

Ovarian cysts in pregnancy most commonly occur during the first trimester. Cysts may become symptomatic due to rupture, hemorrhage, or torsion. The main presenting symptom is acute abdominal pain, with or without signs of hemodynamic instability. Pelvic ultrasound (transabdominal or transvaginal) is used to diagnose ruptured or hemorrhagic ovarian cysts [57]. If the ultrasound diagnosis is uncertain or an adnexal mass is too big to fully assess by ultrasound, non-contrast MRI can be used. Gadolinium-based contrast material should be avoided in pregnancy [56].

Most ovarian cysts in pregnancy will resolve spontaneously. Surgical intervention is required in the case of suspected ovarian torsion. Although most adnexal masses during pregnancy are benign, ectopic and heterotopic pregnancy should be ruled out in patients who present with a symptomatic adnexal mass early in pregnancy.

Uterine fibroids, or leiomyomas, are benign smooth muscle tumors of the uterus. Approximately 20–50% of women of reproductive age have fibroids, and the incidence of fibroids increases with maternal age at pregnancy [58, 59]. During pregnancy, the size of fibroids can fluctuate. The majority does not significantly change in size, but one-third of fibroids may grow in the first trimester. The larger the size of the fibroid, the higher the risk is of adverse events in pregnancy [58, 60, 61].

Most fibroids are asymptomatic in pregnancy, but they can lead to complications including miscarriage, hemorrhage, abdominal pain, preterm labor, malposition of the fetus, red degeneration, retained products of conception, and intrauterine growth restriction (IUGR). The most common complications in order of frequency are abdominal pain (47%), threatened preterm labor, and anemia. Painful fibroids in pregnancy are most often seen in women with large fibroids (>5 cm) during the second and third trimesters of pregnancy. Pain is usually due to “red degeneration,” which is the result of decreased blood supply to the fibroid causing the fibroid to turn red and become necrotic [57–61]. Rupture, hemorrhage, and acute twisting of fibroids also cause pain.