The same abdominal pain differential as non-pregnant patients, plus:
Ectopic pregnancy
First trimester abortion
Complete abortion
Threatened abortion
Inevitable abortion
Incomplete abortion
Missed abortion
Septic abortion
Round ligament stretching<unk> 
Malposition of the<unk> 
Complete abortion
Threatened abortion
Inevitable abortion
Incomplete abortion
Missed abortion
Septic abortion
Labor/Preterm labor
Placental abruption
Placenta previa
Vasa previa
Uterine rupture
Vaginal trauma
HELLP syndrome
Cholestasis of pregnancy
Chorioamnionitis<unk> 
Acute fatty liver of pregnancy
Malposition of the<unk> 
Placenta accreta
Placenta increta
Placenta percreta
Hemorrhagic ovarian cyst
Fibroid degeneration or torsion
Ovarian torsion
Constipation
Obstructive causes
BPH
Prostate cancer
Blood clot
Urethral Stricture
Bladder Calculi
Bladder neoplasm
Foreign body, urethral or bladder
Ovarian/uterine tumor<unk> 
Neurogenic causes
Multiple sclerosis
Parkinson's
Brain tumor
Cerebral vascular disease
Cauda equina syndrome
Spinal cord compression (non-traumatic)
Intervertebral disk herniation
Neuropathy
Nerve injury from pelvic surgery
Postoperative retention
Trauma
Urethral injury
Bladder injury
Spinal cord injury
Extraurinary causes
Perirectal or pelvic abscesses
Rectal or retroperitoneal masses
Fecal impaction
Abdominal Aortic Aneurysm
Psychogenic causes
Psychosexual stress
Acute anxiety
Infection
Cystitis
Prostatitis
Herpes Simplex (genital)
Herpes Zoster involving pelvic region
Local Abscess
PID
Meds
Anticholinergics
Antihistamines
Cold meds
Sympathomimetics
TCA
Muscle relaxants
Opioids
BPH
Prostate cancer
Blood clot
Urethral Stricture
Bladder Calculi
Bladder neoplasm
Foreign body, urethral or bladder
Ovarian/uterine tumor<unk> 
Multiple sclerosis
Parkinson's
Brain tumor
Cerebral vascular disease
Cauda equina syndrome
Spinal cord compression (non-traumatic)
Intervertebral disk herniation
Neuropathy
Nerve injury from pelvic surgery
Postoperative retention
Urethral injury
Bladder injury
Spinal cord injury
Perirectal or pelvic abscesses
Rectal or retroperitoneal masses
Fecal impaction
Abdominal Aortic Aneurysm
Psychosexual stress
Acute anxiety
Cystitis
Prostatitis
Herpes Simplex (genital)
Herpes Zoster involving pelvic region
Local Abscess
PID
Anticholinergics
Antihistamines
Cold meds
Sympathomimetics
TCA
Muscle relaxants
Opioids
Incarcerated uterus
The same abdominal pain differential as non-pregnant patients, plus:
Vaginal foreign body
Ectopic pregnancy
Tubo-ovarian abscess
First trimester abortion
Testicular trauma
Complete abortion