Nancy Fowler Larson

February 09, 2010

February 9, 2010 (Chicago, Illinois) — A simple urine test can rapidly predict and diagnose preeclampsia, according to a study presented here at the Society for Maternal-Fetal Medicine 30th Annual Meeting: The Pregnancy Meeting.

Each year, as many as 76,000 women and 500,000 infants die of severe preeclampsia and eclampsia. Magnesium sulfate can successfully prevent eclamptic seizures, but it is underused in developing countries because identifying appropriate patients requires a laboratory setting, researchers pointed out during the meeting.

In the United States, the lack of an effective test makes it difficult to distinguish mild preeclampsia, severe preeclampsia, and hypertension unrelated to pregnancy. This often results in another negative outcome: physicians inducing labor indiscriminately, resulting in unnecessary prematurity, said investigator Irina Buhimschi, MD, associate professor in the Department of Obstetrics, Gynecology and Reproductive Sciences at Yale University, New Haven, Connecticut, in an interview with Medscape Ob/Gyn and Women's Health.

"It is difficult for physicians to differentiate these cases, and many women end up overdiagnosed in this country because we tend to be overinterventionist [because of] the lawsuit environment," said Dr. Buhimschi. "But in developing countries, where they are not technically advanced [enough] to take care of premature babies, it's the opposite, and many women are underdiagnosed."

Preeclampsia is distinguished by an elevated excretion of misfolded, or misshapen, proteins that are attracted to an azo dye called Congo red. Congo red is also used to locate atypical brain amyloidal aggregates in Alzheimer's and prion disease. The goal of a study led by Dr. Buhimschi was to create and confirm a Congo Red Dot urine test to assess global protein misfolding load during pregnancy.

The study cohort consisted of 347 pregnant women, divided into 3 control groups — women without hypertension (n = 98), those with chronic hypertension (n = 40) and those with gestational hypertension (n = 8) — and 3 preeclampsia groups — those with mild (n = 36), severe (n = 117), and superimposed (n = 33) preeclampsia.

Congo Red Dot urine tests were conducted on 35 asymptomatic women throughout their pregnancies.

Results of all Congo Red Dot urine tests were calculated as a percentage of Congo red retention (CRR). The researchers compared CRR as a predictor of an indicated delivery for preeclampsia with 2 other tests — one for urine protein and another for the ratio of high soluble fms-like tyrosine kinase 1 to placental growth factor (sFlt1/PlGF).

Dr. Buhimschi reported these findings:

  • 61% (211/347) of the subjects had an indicated delivery for preeclampsia, with the highest percentages in those with superimposed preeclampsia (100%), severe preeclampsia (99%), and mild preeclampsia (69%); in the control group, the rate was 4%.

  • CRR levels were higher in women with mild preeclampsia than in those with gestational hypertension, and were even higher in women with severe and superimposed preeclampsia.

  • 11% (4/35) of the asymptomatic women evaluated longitudinally with Congo Red Dot urine testing had preterm indications for delivery for preeclampsia and elevated CRR levels before they developed symptoms.

  • CRR levels more accurately predicted an indicated delivery for preeclampsia than the more intensive urine protein test (P < .001) and sFlt1/PlGF (P = 0.014).

The findings point to the possibility of developing an on-the-spot urine test for predicting and diagnosing preeclampsia, Dr. Buhimschi observed. "It's something that can be done anywhere, even in third-world countries, with results in 10 to 15 minutes," she explained.

Eleni Tsigas, executive director of the Preeclampsia Foundation in Melbourne, Florida, who attended the presentation, is cautious but optimistic about the findings.

"Although the results are too preliminary to start celebrating or to even consider clinical translation, it is encouraging to see novel research being pursued for the diagnosis of preeclampsia," Ms. Tsigas told Medscape Ob/Gyn & Women's Health. "Our current methods are fraught with error, and missing a diagnosis can be deadly."

The study was funded by Yale University's Albert S. McKern endowment. Dr. Buhimschi and Ms. Tsigas disclosed no relevant financial relationships.

Society for Maternal-Fetal Medicine (SMFM) 30th Annual Meeting: The Pregnancy Meeting. Abstract 20. Presented February 4, 2010.

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