Preeclampsia Screening - 1st Trimester

Definition

Preeclampsia (PE) is a pregnancy-related condition characterized by:

• New-onset hypertension (>140/90 mmHg)
• Proteinuria (>0.3 g/24 hours)
• New-onset edema

Most common after 20 weeks of gestation, it can be subdivided into:

• Early PE < 34 weeks
• Intermediate PE between 34 and 37 weeks
• Late PE > 37 weeks

Epidemiology

The prevalence of preeclampsia in Portugal is 2% of pregnancies. Preeclampsia is the leading cause of death (10–15%) for both the child and the mother during pregnancy and is responsible for 12% of stillbirths* and 19% of preterm births in industrialized countries.

_{* FGR—Fetal Growth Restriction}

Etiology

Preeclampsia is a condition that begins early in pregnancy. It results from dysfunction of the uteroplacental bed, involving remodeling of the spiral arteries and hemodynamic impairment, leading to vasoconstriction, platelet aggregation, and hypercoagulability. Clinical manifestations occur only in the second or third trimester.

Diagnosis

The diagnosis of preeclampsia (PE) is based on signs and symptoms and is only possible once the condition manifests:

HELLP Syndrome

If preeclampsia goes undiagnosed, it progresses to HELLP syndrome:

• Hemolysis
• Elevated Liver Enzymes
• Low Platelet Count

Maternal Complications

• Permanent neurological damage
• Renal Failure
• Premature placental abruption of a normally inserted placenta (DPPNI)
• Death
• Recurrence in 25% of pregnancies
• Increased risk of essential hypertension

First-Trimester Screening

• Preeclampsia screening involves estimating the risk of developing the condition before any signs or symptoms appear.
• Screening allows for the early identification of a pregnancy at high risk for preeclampsia and increases the likelihood of a better outcome for that pregnancy.

Detection Rate

• Maternal Age (MA) ≥ 30%
• MA + uA-PI + PAPP-A: 60%
• MA + MAP + uA-PI + PAPP-A = 84%
• MA + MAP + uA-PI + PlGF: 89%
• MA + MAP + uA-PI + PAPP-A + PlGF k 93%

Early prediction of preeclampsia

• Maternal History: A Priori Risk
• +
• Biophysical and Ultrasound Markers (from 11 weeks to 13 weeks + 6 days)
• +
• Biochemical markers (from 10 weeks to 13 weeks + 6 days)
• =
• Combined Risk

Placental Growth Factor (plgf)

• PlGF is produced by the placenta.
• PlGF is an angiogenic factor that acts as a vasodilator, increasing the diameter of existing arteries.
• Low levels of PlGF contribute to vascular dysfunction, which is one of the symptoms of preeclampsia.
• PlGF levels are reduced in a high percentage of pregnancies that progress to preeclampsia.
• This reduction is most pronounced in the first trimester.
• PlGF is the ideal marker for early screening of the risk of preeclampsia.

_{PlGF increases the detection rate of PE by 5%.}

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