Role of sFlt-1/PlGF Ratio in Preeclampsia Detection

Preeclampsia is an important pregnancy complication to recognize early on. It is characterized by high blood pressure after 20 weeks of gestation and may be accompanied by proteinuria, or increased protein levels in the urine indicating kidney damage. If left untreated, preeclampsia can progress to a more severe condition that endangers both the mother and the fetus.

Early detection is key to managing preeclampsia. In addition to monitoring blood pressure and examining urine, a method now used in clinical practice is the sFlt-1/PlGF ratio test. This test helps assess the balance of vascular growth factors related to placental health and can be used to predict or rule out the risk of preeclampsia, especially in cases where the diagnosis is unclear.

Preeclampsia Cases in Indonesia

Preeclampsia occurs in about 5-7% of pregnancies worldwide and is a leading cause of maternal and fetal death, resulting in over 70,000 maternal and 500,000 fetal deaths annually. In Indonesia, the maternal mortality rate increased from 176 to 189 per 100,000 live births from 2021 to 2023 (SDKI). Preeclampsia was recorded at an incidence rate of 5.3% in 2022 and 4.7% in 2023. It accounted for 26.9% of all maternal deaths in 2023.

Symptoms of Preeclampsia

The hallmarks of preeclampsia are high blood pressure and proteinuria, or the presence of protein in the urine. Other signs may include organ damage, particularly to the kidneys and liver. In some cases, preeclampsia develops without obvious symptoms and is often only detected during routine prenatal checkups.

In addition to high blood pressure, symptoms of preeclampsia may include the following:

1. Proteinuria or other signs of impaired kidney function

2. Thrombocytopenia (decreased blood platelet count)

3. Elevated liver enzymes, indicating impaired liver function

4. Severe headaches that do not improve with regular medication

5. Visual disturbances, such as blurred vision, flashes of light, or temporary vision loss

6. Sensitivity to light (photophobia).

7. Shortness of breath due to fluid buildup in the lungs

8. Upper abdominal pain, usually under the right rib cage

9. Nausea or vomiting unrelated to normal pregnancy nausea

Although swelling (edema) and weight gain are common during pregnancy, a sudden onset of swelling, particularly in the face and hands, or sudden weight gain can indicate preeclampsia and require immediate medical attention.

Who is at risk of developing Preeclampsia?

Some conditions that may increase the risk of preeclampsia include:

• First pregnancy

• History of preeclampsia in a previous pregnancy

• Chronic hypertension and/or chronic kidney disease

• History of thrombophilia, a condition that increases the tendency of blood to clot

• In vitro fertilization (IVF) pregnancy

• Family history of pre-eclampsia

• Type 1 or type 2 diabetes

• Body mass index (BMI) ≥ 35 kg/m²

• Maternal age ≤ 20 years or ≥ 40 years

• Long gestation interval since the last pregnancy

The Role of the sFlt-1/PlGF Ratio in Detecting Preeclampsia

Although the exact cause of preeclampsia is not fully understood, one theory suggests that the condition is triggered by a disruption in the placenta. Imbalances in proteins produced by the placenta can lead to endothelial dysfunction, or damage to the lining of the mother's blood vessels. This can trigger high blood pressure and other complications.

The two main proteins involved in this process are:

• sFlt-1 (soluble fms-like tyrosine kinase-1), which is antiangiogenic and inhibits blood vessel formation, and

• PlGF (placental growth factor): proangiogenic (promotes blood vessel formation).

  
  

How does preeclampsia affect the body?

During a normal pregnancy, the placenta produces proteins that maintain a balance in blood vessel formation. This ensures optimal blood flow to the fetus. In preeclampsia, however, the production of sFlt-1 increases abnormally, which inhibits the function of PlGF. This imbalance disrupts the placental and maternal blood vessels, leading to symptoms such as high blood pressure, protein in the urine, and impaired kidney, liver, and other organ function.

These changes occur before clinical symptoms appear. Therefore, the sFlt-1/PlGF ratio test can provide an early indication of impaired placental function and help predict the risk of developing severe preeclampsia in the near future.

When should the sFlt-1/PlGF Ratio Check be Performed?

The sFlt-1/PlGF ratio test is recommended for pregnant women with suspected preeclampsia, especially if one or more of the following conditions are met:

• Gestational age between 20 to 34 weeks, and suspicion of pre-eclampsia

• Proteinuria, ie:

• Urine dipstick test result ≥ 1+, or

• 24-hour urine examination shows protein levels ≥ 300 mg/L

• Stunted fetal growth (IUGR)

• Liver function abnormalities, based on laboratory examination results

• Previous history of preeclampsia or family history of preeclampsia

• History of chronic hypertension

• Kidney disease

• Diabetes mellitus

• Twin pregnancy or fetal movement disorder (reduced fetal movement)

The sFlt-1/PlGF ratio test is a useful tool for assessing preeclampsia risk, particularly in patients with unspecified clinical manifestations. While it does not replace other clinical and laboratory tests, the test can provide information to help medical personnel determine the need for further monitoring or referral. Integrating this test into antenatal care is expected to improve detection accuracy and accelerate targeted management of preeclampsia.

Source:

• Mayo Clinic – Preeclampsia

• Dinas Kesehatan Provinsi Sumatera Selatan. Profil Dinas Kesehatan Provinsi Sumatera Selatan. 2023

• Mayo Clinic - Preeclampsia sFlt-1/PIGF (Soluble fms-Like Tyrosine Kinase 1

• SCL Guide book, 2025