Abdominal pain in pregnancy

Can't Miss Diagnoses in the Pregnant Patient With Abdominal Pain

Dr.Tana Kiak

Specialist:Obstetrics & Gynecology

Contact: [email protected]

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Abdominal pain during the first trimester of pregnancy is a common presenting complaint. There are many conditions specific to and related only to pregnancy; however, it is important to remember that any condition causing pain in the non-obstetric patient may also occur in the obstetric patient, although the presenting history and physical examination may be different. Evaluating the pregnant patient with abdominal pain has inherent challenges because nausea, vomiting, and abdominal pain are common in the normal obstetric population. The expanding uterus can displace other intra-abdominal organs and anemia and leukocytosis are common in normal pregnancies and are not as predictive of blood loss or infection. The ultrasound image demonstrates intrauterine fluid and debris without evidence of an intrauterine pregnancy in a patient with an ectopic pregnancy.

http://reference.medscape.com/features/slideshow/abdominal-pain?src=mp

Normal implantation of the embryo into the uterine lining (illustration shown) can be associated with mild, intermittent cramping that lasts 1 or 2 days and a small amount of vaginal bleeding, called implantation bleeding. The spotting is often minimal and occurs between 6 and 12 days after the date of suspected conception, often on or around the same day as the next expected period. Hence, patients can often mistake it for a mild period.


Ectopic pregnancy is the leading cause of first trimester pregnancy-related mortality in the United States, and accounts for 2% of all pregnancies and 9% of all pregnancy-related deaths. An ectopic pregnancy most often occurs due to an abnormality in anatomy or function of the fallopian tube, ovary, or uterus, although approximately 95% of ectopic pregnancies occur in the fallopian tube. Anything that impedes the migration of the embryo to the endometrial cavity could predispose women to an ectopic pregnancy. Risk factors include pelvic inflammatory disease, age, previous ectopic pregnancy, previous tubal ligation, tobacco use, age > 35 years, progesterone-bearing intrauterine devices, and fertility treatment with ovulation induction or ovarian stimulation.


When concern for an ectopic pregnancy exists, a serum quantitative human chorionic gonadotropin (hCG) level is often used to determine if the discriminatory zone has been passed. The discriminatory zone is the level of hCG at which a normal intrauterine pregnancy should be visible with transvaginal ultrasound. Many studies suggest that a gestational sac should be seen by 5.5 weeks' gestation or with an hCG level of 1500-2400 mIU/mL for transvaginal ultrasound. If the hCG level is higher than the discriminatory zone and no gestational sac is seen in the uterus, then an ectopic pregnancy cannot be excluded. The image shown is a transverse grayscale ultrasound image of a gestational sac with yolk sac (arrow) indicating an intrauterine pregnancy.


By 6 weeks' gestation, all normal pregnancies (defined by a visible yolk sac, a fetal pole, or cardiac motion) should be visible with vaginal ultrasound. The usual finding for an ectopic pregnancy on ultrasound is a mass in the adnexa, fluid in the pelvis, and no visible intrauterine pregnancy. Conclusive diagnosis of ectopic by vaginal probe ultrasound, seen in only about 20% of ectopics, can only be made if fetus or fetal cardiac motion is seen outside the uterus. Heterotopic pregnancies (intrauterine pregnancy + ectopic) are very rare, accounting for 1:5000 pregnancies without fertility agent. The image shown is of an endovaginal sonogram demonstrating an early ectopic pregnancy. An echogenic ring (tubal ring) (arrow) found outside of the uterus can be seen in this view.


An ectopic pregnancy should be considered a medical emergency because virtually all ectopic pregnancies are considered nonviable and at risk for eventual rupture. The death rate from ectopic pregnancies is about 1 per 2000, resulting in at least 50 patient deaths each year in the United States. from rupture of an ectopic pregnancy and the resulting hemorrhage. No combination of history and physical elements can reliably exclude an ectopic pregnancy. Unless an intrauterine pregnancy has already been confirmed, any patient with amenorrhea, abdominal pain, vaginal bleeding, syncope, or hemodynamic instability should be considered to have a potential ectopic pregnancy until proven otherwise. This laparoscopic image is of an unruptured right ampullary ectopic pregnancy (arrow) with bleeding out of the fimbriated end of the fallopian tube resulting in hemoperitoneum.


Treatment for ectopic pregnancy may be medical or surgical. Medical treatment often involves the use of methotrexate (MTX). Criteria for MTX therapy include unruptured ectopic mass < 4 cm on ultrasound or 3.5 cm if cardiac activity is seen, beta-hCG < 5000 mIU/mL, hemodynamic stability, no hepatic or renal disease, white blood cell count > 2000 cells/µL, and platelet count > 100,000 platelets/µL. The patient's decreasing beta-hCG level is then often followed on an outpatient basis. The success rate of MTX is 35% for beta-hCG > 4000 mIU/mL. MTX treatment can result in nausea and vomiting, increased abdominal pain (up to 60%), and tubal rupture (4%). In hemodynamically unstable patients or those who do not meet MTX criteria, surgery may be required. Shown is a laparoscopic image of an ampullary ectopic pregnancy protruding (arrow) after a linear salpingostomy was performed.


Any vaginal bleeding during early pregnancy without cervical dilatation or change in cervical consistency is considered a threatened abortion. An abortion is the spontaneous (miscarriage) or induced (medical or surgical) loss of a pregnancy prior to fetal viability outside of the uterus. Early pregnancy is often considered to end at 20 weeks' gestation. Spontaneous abortions are common in the first trimester and are divided into 4 stages: threatened, inevitable, incomplete, and complete. Twenty-five percent to 30% of all pregnancies have bleeding during the pregnancy and less than 50% proceed to a complete abortion. This endovaginal ultrasound

(shown) reveals an approximate 6-week intrauterine pregnancy. http://reference.medscape.com/features/slideshow/abdominal-pain?src=mp

An inevitable abortion is an early pregnancy with a dilatation of the cervix, although no tissue has yet passed. Symptoms of abdominal cramping and vaginal bleeding are often worse than with a threatened abortion. An ultrasound may reveal products of conception located in the lower uterine segment or the cervical canal. Lack of fluid surrounding this 8-week embryo (arrow) resulted in a disproportionately small sac. A follow-up scan 1 week later revealed fetal demise.


An incomplete abortion is an early pregnancy that is associated with dilatation of the cervix, heavy vaginal bleeding, and intense abdominal cramping with passage of products of conception. Tissue and large blood clots may provide evidence of tissue passage within the vagina. Ultrasound may show that some of the products of conception are still present in the uterus. This image shows an endovaginal longitudinal view of a low-lying gestational sac (GS) within the uterus (Ut), representing an incomplete miscarriage. A complete abortion is a completed miscarriage.


An ovarian cyst is a sac filled with fluid arising in an ovary (arrows). Ovarian cysts during pregnancy occur at a ratio of about 1 in 1000 women. During pregnancy, large cysts may rupture or result in ovarian torsion, resulting in severe abdominal pain and increasing the risk for miscarriage or preterm labor. If they do not decrease in size spontaneously over the course of a few weeks, large (more than 6-8 cm) cysts are usually removed surgically. The best time to operate in pregnancy is the second trimester around 14-16 weeks. The vast majority of ovarian cysts are benign, although the incidence of ovarian cancer is 1 in 25,000 births.


Ovarian torsion is an infrequent, but important, cause of acute abdominal pain and results in the total or partial rotation of the ovary around its vasculature axis. Ovarian torsion occurs far more commonly during pregnancy than in the nonpregnant patient. Torsion of a normal ovary is rare and the typical presentation is a unilateral torsion of a pathologically enlarged ovary. Early on, continued arterial flow with blockage of the venous and lymphatic channels may result in enlargement of the ovary. If the torsion remains undiagnosed or untreated, arterial stasis can lead to hemorrhagic infarction and necrosis of the ovary. Adnexal torsion almost always involves both the ovary and fallopian tube and isolated ovarian torsion is rare. The mobility of the left ovary tends to be limited by the sigmoid colon, hence about two thirds of adnexal torsions are right-sided. This image reveals an ovarian cyst that has undergone torsion.


Uterine leiomyomas (fibroids) are benign growths in the wall of the uterus (arrows) and affect more than 20% of reproductive-aged women. Most are small and asymptomatic, although when enlarged they can cause a mass effect, resulting in pelvic pressure and pain or a distortion of the uterine wall or endometrial cavity, which leads to abnormal uterine bleeding. It appears that there is an increased risk for pregnancy loss associated with the presence of uterine fibroids in early pregnancy, especially with multiple fibroids.


Appendicitis develops in pregnant women with the same frequency as nonpregnant women of the same age, and the cases are equally distributed throughout the 3 trimesters of pregnancy. Appendicitis is the most common nonobstetric cause of an acute surgical abdomen in the pregnant patient, affecting 1 in 1500 pregnancies and if undiagnosed can be a potentially fatal surgical emergency. Ruptured appendicitis is also associated with a 30% chance of fetal loss, vs a 3%-5% risk without rupture. Appendectomy during pregnancy is often followed by preterm labor but rarely by preterm delivery. This image shows a normal appendix (blue arrow) in a pregnant patient (orange arrow = fetus).


Gallstones (cholelithiasis) develop in women at twice the risk as men, and hormonal changes that occur during pregnancy can put patients at even higher risk. Cholelithiasis is one of the most common abnormalities found on bedside ultrasonography. Ultrasonography has a sensitivity of 95% in the diagnosis of cholelithiasis. Symptomatic patients often experience severe right upper quadrant abdominal pain with associated nausea and vomiting. Depending on symptoms and risk factors, patients may be monitored or undergo emergent cholecystectomy. A gallstone (yellow arrow) is seen as a hyperechoic, well-defined focal lesion, typically with an acoustic shadow (white arrow), situated on the dependent portion of the gallbladder wall.


Acute cholecystitis is the sudden inflammation of the gallbladder that causes severe abdominal pain often associated with nausea and vomiting. In 90% of cases, acute cholecystitis is caused by gallstones. Once diagnosed, management is initially conservative and includes antibiotic therapy. Subsequent management depends on the gestational age at diagnosis. Surgical therapy, when indicated, should not be delayed and a planned intervention during the second trimester appears to offer a better outcome than surgery performed under emergent conditions. Acute cholecystitis findings on ultrasonography may include dilatation, stones, a thickened gallbladder wall (> 4 mm; yellow arrow and circle), wall edema (target signs), pericholecystic fluid, and a positive

sonographic Murphy sign.http://reference.medscape.com/features/slideshow/abdominal-pain?src=mp

Urinary tract infections are more common during pregnancy because of changes in the urinary tract. The uterus sits directly on top of the bladder. As the uterus grows, its increased weight can block the drainage of urine from the bladder, causing an infection. Suprapubic abdominal pain with dysuria, urgency, and frequency are common. The image shown demonstrates urinary sediment with visible white blood cells (yellow arrow) and bacteria (red arrow).


Round ligament pain is caused by the stretching of the round ligaments (arrow), which suspend the uterus in the abdomen. As the uterus grows and stretches, these ligaments pull on nearby nerve fibers, causing pain. A ligament spasm, an involuntary contraction or cramp, usually triggers a sharp pain. These spasms are found more frequently on the right side than the left because of the normal tendency of the uterus to turn to the right. Image courtesy of Wikimedia Commons.


Ultrasonography is the most frequently used radiologic modality for evaluating the pregnant abdomen. Extensive experience documents the safety of ultrasonography in pregnancy. The maternal gallbladder, pancreas, and kidneys can be evaluated easily. Ultrasonography is also used with graded compression as a diagnostic aid for appendicitis. Ionizing radiation in the first trimester pregnant patient with abdominal pain is a source of anxiety, but limited radiation exposure does not result in harmful fetal effects. If multiple diagnostic procedures are needed, remember that exposure to less than 50 mGy (Gray) has not been associated with an increase in fetal anomalies or pregnancy loss. During pregnancy, perform medically indicated diagnostic radiograph procedures when needed, but consider other imaging modalities when possible.

Data from McCollough et al. Radiographics. 2007;27:909-917.


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Abdominal pain in pregnancy