Pelvic Pain During Early Pregnancy: A Merck Manual of Patient Symptoms podcast

Pelvic pain is common during early pregnancy and may accompany serious or minor disorders. Some conditions causing pelvic pain also cause vaginal bleeding. In some of these disorders (eg, ruptured ectopic pregnancy, ruptured hemorrhagic corpus luteum cyst), bleeding may be severe, sometimes leading to hemorrhagic shock.

Causes of upper and generalized abdominal pain are similar to those in nonpregnant patients.

Etiology

Causes of pelvic pain during early pregnancy (see Table 1: Symptoms During Pregnancy: Some Causes of Pelvic Pain During Early Pregnancy) may be

• Obstetric
• Gynecologic, nonobstetric
• Nongynecologic

Sometimes no particular disorder is identified.

The most common obstetric cause is

• Spontaneous abortion (threatened, inevitable, incomplete, complete, septic, or missed)

The most common serious obstetric cause is

• Ruptured ectopic pregnancy

Nonobstetric gynecologic causes include adnexal torsion, which is more common during pregnancy because during pregnancy, the corpus luteum causes the ovaries to enlarge, increasing the risk of the ovary twisting around the pedicle.

Common nongynecologic causes include various common GI and GU disorders:

• Viral gastroenteritis
• Irritable bowel syndrome
• Appendicitis
• Inflammatory bowel disease
• UTI
• Nephrolithiasis

Pelvic pain during late pregnancy may result from labor or one of the many nonobstetric causes of pelvic pain.

Table 1
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Some Causes of Pelvic Pain During Early Pregnancy Cause Suggestive Findings Diagnostic Approach Obstetric disorders Ectopic pregnancy Abdominal or pelvic pain, which is often sudden, localized, and constant (not crampy), with or without vaginal bleeding Closed cervical os No fetal heart sounds Possibly hemodynamic instability if ectopic pregnancy has ruptured Quantitative β-hCG measurement CBC Blood type and Rh typing Pelvic ultrasonography Spontaneous abortion (threatened, inevitable, incomplete, complete, missed) Crampy, diffuse abdominal pain, often with vaginal bleeding Open or closed cervical os depending on the type of abortion (see Table 2: Symptoms During Pregnancy: Some Causes of Vaginal Bleeding During Early Pregnancy) Evaluation as for ectopic pregnancy Septic abortion Usually, apparent history of recent instrumentation of the uterus or induced abortion (often illegal or self-induced) Fever, chills, constant abdominal or pelvic pain with a purulent vaginal discharge Open cervical os Evaluation as for ectopic pregnancy plus cervical cultures Normal changes of pregnancy, including those due to stretching and growth of the uterus during early pregnancy Crampy or burning sensation in the lower abdomen, pelvis, lower back, or a combination Evaluation as for ectopic pregnancy Diagnosis of exclusion Nonobstetric gynecologic disorders Uterine fibroid degeneration Sudden onset of pelvic pain, often with nausea, vomiting, and fever Sometimes vaginal bleeding Evaluation as for ectopic pregnancy Adnexal (ovarian) torsion Sudden onset of localized pelvic pain, which may be colicky and often mild if torsion spontaneously resolves Often, nausea, vomiting Evaluation as for ectopic pregnancy plus Doppler ultrasonography Ruptured corpus luteum cyst Localized abdominal or pelvic pain, sometimes mimicking adnexal torsion Vaginal bleeding Usually, sudden onset Evaluation as for ectopic pregnancy plus Doppler ultrasonography Pelvic inflammatory disease (uncommon during pregnancy) Cervical discharge, significant adnexal tenderness Evaluation as for ectopic pregnancy plus cervical cultures Nongynecologic disorders Appendicitis Usually, continuous pain, tenderness Possibly atypical location (eg, right upper quadrant) or qualities (milder, crampy, no peritoneal signs) compared with pain in nonpregnant patients Evaluation as for ectopic pregnancy plus cervical cultures Pelvic/abdominal ultrasonography Consideration of CT if ultrasonography is inconclusive UTI Suprapubic discomfort, often with bladder symptoms (eg, burning, frequency, urgency) Urinalysis and culture Inflammatory bowel disease Variable pains (crampy or constant) in no consistent location, often with diarrhea and sometimes with mucus or blood Usually, a known history Clinical evaluation Sometimes endoscopy Bowel obstruction Colicky pain, vomiting, no bowel movements or flatus Distended, tympanitic abdomen Usually, history of abdominal surgery (causing adhesions) or sometimes an incarcerated hernia detected during examination Evaluation as for ectopic pregnancy plus cervical cultures Pelvic/abdominal ultrasonography Consideration of CT if ultrasonography is inconclusive Gastroenteritis Usually, vomiting, diarrhea No peritoneal signs Clinical evaluation *β-hCG = β subunit of human chorionic gonadotropin. Some Causes of Pelvic Pain During Early Pregnancy Cause Suggestive Findings Diagnostic Approach Obstetric disorders Ectopic pregnancy Abdominal or pelvic pain, which is often sudden, localized, and constant (not crampy), with or without vaginal bleeding Closed cervical os No fetal heart sounds Possibly hemodynamic instability if ectopic pregnancy has ruptured Quantitative β-hCG measurement CBC Blood type and Rh typing Pelvic ultrasonography Spontaneous abortion (threatened, inevitable, incomplete, complete, missed) Crampy, diffuse abdominal pain, often with vaginal bleeding Open or closed cervical os depending on the type of abortion (see Table 2: Symptoms During Pregnancy: Some Causes of Vaginal Bleeding During Early Pregnancy) Evaluation as for ectopic pregnancy Septic abortion Usually, apparent history of recent instrumentation of the uterus or induced abortion (often illegal or self-induced) Fever, chills, constant abdominal or pelvic pain with a purulent vaginal discharge Open cervical os Evaluation as for ectopic pregnancy plus cervical cultures Normal changes of pregnancy, including those due to stretching and growth of the uterus during early pregnancy Crampy or burning sensation in the lower abdomen, pelvis, lower back, or a combination Evaluation as for ectopic pregnancy Diagnosis of exclusion Nonobstetric gynecologic disorders Uterine fibroid degeneration Sudden onset of pelvic pain, often with nausea, vomiting, and fever Sometimes vaginal bleeding Evaluation as for ectopic pregnancy Adnexal (ovarian) torsion Sudden onset of localized pelvic pain, which may be colicky and often mild if torsion spontaneously resolves Often, nausea, vomiting Evaluation as for ectopic pregnancy plus Doppler ultrasonography Ruptured corpus luteum cyst Localized abdominal or pelvic pain, sometimes mimicking adnexal torsion Vaginal bleeding Usually, sudden onset Evaluation as for ectopic pregnancy plus Doppler ultrasonography Pelvic inflammatory disease (uncommon during pregnancy) Cervical discharge, significant adnexal tenderness Evaluation as for ectopic pregnancy plus cervical cultures Nongynecologic disorders Appendicitis Usually, continuous pain, tenderness Possibly atypical location (eg, right upper quadrant) or qualities (milder, crampy, no peritoneal signs) compared with pain in nonpregnant patients Evaluation as for ectopic pregnancy plus cervical cultures Pelvic/abdominal ultrasonography Consideration of CT if ultrasonography is inconclusive UTI Suprapubic discomfort, often with bladder symptoms (eg, burning, frequency, urgency) Urinalysis and culture Inflammatory bowel disease Variable pains (crampy or constant) in no consistent location, often with diarrhea and sometimes with mucus or blood Usually, a known history Clinical evaluation Sometimes endoscopy Bowel obstruction Colicky pain, vomiting, no bowel movements or flatus Distended, tympanitic abdomen Usually, history of abdominal surgery (causing adhesions) or sometimes an incarcerated hernia detected during examination Evaluation as for ectopic pregnancy plus cervical cultures Pelvic/abdominal ultrasonography Consideration of CT if ultrasonography is inconclusive Gastroenteritis Usually, vomiting, diarrhea No peritoneal signs Clinical evaluation *β-hCG = β subunit of human chorionic gonadotropin.

Evaluation

Evaluation should exclude potentially serious treatable causes (eg, ruptured or unruptured ectopic pregnancy, septic abortion, appendicitis).

History : History of present illness should include the patient's gravidity and parity as well as the pain's onset (sudden or gradual), location (localized or diffuse), and character (crampy or colicky). A history of illicitly attempted termination of pregnancy suggests septic abortion, but absence of this history does not exclude this diagnosis.

Review of systems should seek GU and GI symptoms that suggest a cause. Important GU symptoms include vaginal bleeding (ectopic pregnancy or abortion); syncope or near syncope (ectopic pregnancy); urinary frequency, urgency, or dysuria (UTI); and vaginal discharge and history of unprotected intercourse (pelvic inflammatory disease). Important GI symptoms include diarrhea (gastroenteritis, inflammatory bowel disease, or irritable bowel syndrome), vomiting (due to many disorders, including gastroenteritis and bowel obstruction), and obstipation (bowel obstruction, irritable bowel, or a functional disorder).

Past medical history should seek disorders known to cause pelvic pain (eg, inflammatory bowel disease, irritable bowel syndrome, nephrolithiasis, ectopic pregnancy, spontaneous abortion). Risk factors for these disorders should be identified.

Risk factors for ectopic pregnancy include

• History of sexually transmitted disease or pelvic inflammatory disease
• Cigarette smoking
• Use of intrauterine device
• Age > 35
• Previous abdominal surgery (especially tubal surgery)
• Use of fertility drugs or assisted reproductive techniques
• Previous ectopic pregnancy (the most important)
• Multiple sex partners
• Douching

Risk factors for spontaneous abortion include

• Age > 35
• History of spontaneous abortion
• Cigarette smoking
• Drugs (eg, cocaine, alcohol, high doses of caffeine)
• Uterine abnormalities (eg, leiomyoma, adhesions)

Risk factors for bowel obstruction include

• Previous abdominal surgery
• Hernia

Physical examination: Physical examination begins with a review of vital signs, particularly for fever and signs of hypovolemia (hypotension, tachycardia).

Evaluation focuses on abdominal and pelvic examinations. The abdomen is palpated for tenderness, peritoneal signs (rebound, rigidity, guarding), and uterine size and is percussed for tympany. Fetal heart sounds are checked using a Doppler probe.

Pelvic examination includes inspection of the cervix for discharge, dilation, and bleeding. Discharge, if present, should be sampled and sent for culture. Any blood or clots in the vaginal vault are gently removed. Bimanual examination should check for cervical motion tenderness, adnexal masses or tenderness, and uterine size.

Red flags: The following findings are of particular concern:

• Hemodynamic instability (hypotension, tachycardia, or both)
• Syncope or near syncope
• Peritoneal signs (rebound, rigidity, guarding)
• Fever, chills, and purulent vaginal discharge
• Vaginal bleeding

Interpretation of findings: Certain findings suggest causes of pelvic pain but are not always diagnostic (see Table 1: Symptoms During Pregnancy: Some Causes of Pelvic Pain During Early Pregnancy).

For all women who present with pelvic pain during early pregnancy, the most serious cause—ectopic pregnancy—must be excluded, regardless of any other findings. Nonobstetric causes of pelvic pain (eg, acute appendicitis) must always be considered and investigated as in nonpregnant women.

As in any patient, findings of peritoneal irritation (eg, focal tenderness, guarding, rebound, rigidity) are a concern. Common causes include appendicitis, ruptured ectopic pregnancy, and, less often, ruptured ovarian cyst. However, absence of peritoneal irritation does not rule out such disorders, and index of suspicion must be high.

Vaginal bleeding accompanying the pain suggests spontaneous abortion or ectopic pregnancy. An open cervical os or tissue passed through the cervix strongly suggests an inevitable, incomplete, or complete abortion. The presence of fever, chills, and a purulent vaginal discharge suggests a septic abortion (particularly in patients with a history of instrumentation of the uterus or illicitly attempted termination of pregnancy). Pelvic inflammatory disease is rare during pregnancy but may occur.

Testing: If an obstetric cause of pelvic pain is suspected, quantitative measurement of β-hCG, CBC, blood type, and Rh typing should be done. If the patient is hemodynamically unstable (with hypotension, persistent tachycardia, or both), blood should be cross-matched, and fibrinogen level, fibrin split products, and PT/ PTT are determined.

Pelvic ultrasonography is done to confirm an intrauterine pregnancy. However, ultrasonography can and should be deferred in the hemodynamically unstable patient with a positive pregnancy test, given the very high likelihood of either ectopic pregnancy or spontaneous abortion with hemorrhage. Both transabdominal and transvaginal ultrasonography should be used as necessary. If the uterus is empty and tissue has not been passed, ectopic pregnancy is suspected. If Doppler ultrasonography shows that blood flow to the adnexa is absent or decreased, adnexal (ovarian) torsion is suspected. However, this finding is not always present because spontaneous detorsion can occur.

Treatment

Treatment is directed at the cause. If ectopic pregnancy is confirmed and is not ruptured, methotrexateSome Trade Names
RHEUMATREX
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can often be considered, or surgical salpingotomy or salpingectomy may be done. If the ectopic pregnancy is ruptured or leaking, treatment is immediate laparoscopy or laparotomy.

Treatment of spontaneous abortions depends on the type of abortion and the patient's hemodynamic stability. Threatened abortions are treated conservatively with oral analgesics. Inevitable, incomplete, or missed abortions are treated medically with misoprostolSome Trade Names
CYTOTEC
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or surgically with uterine evacuation via D & C. Septic abortions are treated with uterine evacuation plus IV antibiotics.

Women who have Rh-negative blood should be given Rh₀(D) immune globulin if they have vaginal bleeding or an ectopic pregnancy.

Ruptured corpus luteum cysts and degeneration of a uterine fibroid are treated conservatively with oral analgesics.

Treatment of adnexal torsion is surgical: manual detorsion if the ovary is viable; oophorectomy or salpingectomy if the ovary is infarcted and nonviable.

Key Points

• Clinicians should always be alert for ectopic pregnancy.
• Nonobstetric causes should be considered; acute abdomen may develop during pregnancy.
• If no clear nonobstetric cause is identified, ultrasonography is usually necessary.
• A septic abortion is suspected when there is a history of recent uterine instrumentation or induced abortion.
• If vaginal bleeding occurred, Rh status is determined, and all women with Rh-negative blood are given Rh₀(D) immune globulin.

Last full review/revision August 2009 by R. Phillips Heine, MD; Geeta K. Swamy, MD

Content last modified February 2012