The diagnosis of pregnancy and some of its potential complications focus on 3 diagnostic tools:
- History and physical exam
- Hormonal assays
- Ultrasonography
SIGNS AND SYMPTOMS 
- Amenorrhea accompanied by nausea and vomiting in a sexually active woman
- Amenorrhea:
- Most common cause of secondary amenorrhea in a woman of reproductive age is pregnancy
- Nausea and vomiting (morning sickness)
- Breast tenderness (mastodynia)
- Urinary frequency
- Headache
- Low back pain
- Pica
- Edema of feet and ankles
- Weight gain
- Easy fatigability, generalized malaise
- Increase in abdominal girth
- Constipation
- Heartburn
- Excessive eructation
- Skin darkening
History
- Determine 1st day of last menstrual period (FDLMP)
- 40% of women cannot accurately remember their FDLMP
Physical Exam
Pelvic exam:
- Estimate expected date of delivery by determining uterine fundal height
- Centimeters from pubic bone to top of uterus approximates gestational age after 16 wk
- Detect abnormal pelvic pain or masses
DIAGNOSIS TESTS & INTERPRETATION
Lab
- Pregnancy tests:
- β-subunit of hCG
- Quantitative hCG normally doubles every 2 days until 6–7 wk gestation
- Progesterone
- Measurement of β-hCG:
- Most urine pregnancy tests have sensitivity at 25 mIU/mL:
- False-negative tests with dilute urine and high vitamin C intake
- Home pregnancy tests are not that accurate:
- Detect pregnancy 9–12 days post conception
- Positive home pregnancy tests should be confirmed by serum hCG levels.
- Serum level of hCG:
- Detectable 8–11 days post conception
- hCG levels may remain detectable up to 60 days after an abortion.
- Serum progesterone level is an indicator of the viability of the pregnancy and may be used to predict the outcome of the pregnancy:
- A serum progesterone level of < 5 ng/mL is indicative of a nonviable pregnancy (spontaneous abortion or ectopic pregnancy).
- Progesterone level 25 ng/mL denotes a viable pregnancy.
Imaging
- Ultrasonography is used to confirm pregnancy in the setting of abdominal pain, vaginal bleeding, or some other potential obstetric complication:
- Can estimate gestational age
- Confirm intrauterine or ectopic pregnancy
- Evaluate fetal viability
- Identify fetal abnormalities
- Transabdominal US vs. transvaginal US:
- Transvaginal US is more sensitive but more difficult to perform.
- Intrauterine pregnancy seen at 4–5 wk in transvaginal US
- Gestational sac seen at 5.5–6 wk in transabdominal US
- Transvaginal US is contraindicated in the setting of premature rupture of membranes and 3rd-trimester bleeding.
- When used in combination with hCG levels, US is a very helpful tool in detecting abnormal/problem pregnancy.
- MRI: No significant side effects have been documented.
- Often the study of choice to evaluate for appendicitis in pregnancy
- Plain radiography and CT:
- Dose-dependent teratogen
- Slight increase in risk of childhood cancer
- Goal is to not exceed 5,000 mrad fetal dose of radiation:
- CXR with abdominal shield: < 1 mrad
- Abdominal plain film: 240 mrad
- Chest CT: < 10 mrad
- Head CT: < 10 mrad
- Abdominal CT with and without contrast: 2,000 and 1,000 mrad
- Cardiac catheterization: 1,300 mrad
- VQ scan: < 50 mrad
DIFFERENTIAL DIAGNOSIS
Any woman who is of the age to be sexually active who presents to the ED should be assumed to be pregnant until proven otherwise.
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PRE-HOSPITAL
- Assume the patient is pregnant
- Administer medications only when necessary to avoid teratogenetic side effects or placental–fetal compromise (e.g., epinephrine)
- If > 24 wk gestation, transport in left lateral recumbent position
INITIAL STABILIZATION/THERAPY
- Advanced cardiac life support, advanced trauma life support measures as needed: Oxygen, cardiac monitor, IV access, and fluids:
- 1st objective is to resuscitate mother
- If > 24 wk gestation, place in the left lateral recumbent position
ED TREATMENT/PROCEDURES
The goal is to optimize maternal condition to improve fetal condition.
MEDICATION
- 1st trimester is when organogenesis is occurring.
- Fetal malformation continues beyond the 1st trimester.
- Before using any drug, refer to its Food and Drug Administration safety classification in pregnancy:
- This classification system categorizes drugs as A, B, C, D, and X, with category A being the safest and category X being the most toxic.
- Analgesics: Acetaminophen is the preferred OTC analgesic
- Aspirin and NSAIDs are not teratogenic but are best used in consultation with an obstetrician
- Oxycodone, codeine, hydrocodone, meperidine, and morphine have no known teratogenic affect and can be used for the control of severe pain in pregnancy for short periods of time (3–4 days).
- Antibiotics: Selecting the right antibiotic in a gravid female depends on 3 factors:
- Maternal drug allergies
- Gestational age
- Type of infections and associated pathogens
- Consider placing patient on prenatal vitamins
- Pain control:
- Acetaminophen: 500 mg PO q6h; do not exceed 4g/d
- Antiemetic:
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DISPOSITION
Admission Criteria
- Pregnant women with the following obstetric complications should be admitted to the hospital:
- Pregnant women with medical conditions that would warrant admission in a nongravid female.
Discharge Criteria
Women without the above conditions may be discharged from the ED.
FOLLOW-UP RECOMMENDATIONS
Need OB follow up for prenatal care by 6–8 wk gestation
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