The hPL test, also known as the human chorionic somatomammotropin test, is performed to evaluate placental function as an index of fetal well-being in at-risk pregnancies. hPL is a growth-promoting hormone of placental origin and is similar to hCG (see Hormone Testing). The level of hPL correlates best with placental weight, but the clinical significance of this hormone is controversial. Low hPL levels are associated with fetal growth restriction. Falling levels indicate a poor prognosis.

1. Obtain a serum sample of at least 1 mL in two separate vials (red-topped tube) by venipuncture. Observe standard precautions.

2. Record the week of gestation or last menstrual period on the test requisition or computer screen. These tests are usually done as serial measurements.

1. Normal values are associated with normal intrauterine growth but do not ensure lack of complications.

2. Decreased or falling values are associated with:

   1. Growth restriction

   2. Placental disease

   3. Fetal death

   4. Hypertensive state

   5. Toxemia

   6. Aborting hydatidiform mole

   7. Choriocarcinoma

   8. Placental insufficiency

3. Low levels are also associated with some normal pregnancies.

4. Increased values are found in:

   1. Multifetal pregnancy (twins or more)

   2. Placental site trophoblastic tumor

   3. Intact molar pregnancy

   4. Diabetes

   5. Rh incompatibility

Pretest Patient Care

1. Explain the reason for testing the patient’s blood.

2. Follow guidelines in Chapter 1 for safe, effective, informed pretest care.

Administration of radiopharmaceuticals 24 hours before venipuncture interferes with this test.

Normal

• Normal maternal serum: <0.5 μg/mL (<0.5 mg/L or <25 nmol/L)

  • First trimester: 0.2–2.1 μg/mL

  • Second trimester: 0.5–6.7 μg/mL

  • Third trimester: 4.5–12.8 μg/mL

• Men and nonpregnant women: 0–0.1 μg/mL