Blood Test Predicts Low Birth Weight

A protein found in the blood of pregnant women can predict if they are likely to have a fetus that does not grow properly.

The assay could lead to a widely available blood test that could help develop ways for improving the outcomes of women and their children who face this high risk of stillbirth and long-term health complications.

Scientists at the Ottawa Hospital Research Institute (ON, Canada) conducted a nested case-control study to examine circulating levels of Insulin Growth Factor Binding Protein 4 (IGBP-4) and other biomarkers by Western blot in early gestation in 36 women who went on to develop fetal growth restriction (FGR) and 36 controls having normal-weight babies.

The investigators found that IGFBP-4 was elevated in early pregnancy compared with nonpregnant women and women in later pregnancy, consistent with the presence of abundant extravillous trophoblasts and decidual cells that highly expressed IGFBP-4. High expression of pregnancy-associated plasma protein-A (PAPP-A) was observed in extravillous trophoblasts and decidual cells in early pregnancy but hardly detectable in the circulation at the same time. The women with high levels of IGFBP-4 were 22 times more likely to give birth to tiny babies, defined as the smallest 5% by weight for their gestational age, than women with normal levels of IGFBP-4.

Andrée Gruslin, MD, the lead author of the study, said, "Usually, we don’t find out until later in a pregnancy that a fetus isn’t growing properly, but this test can tell us in the first trimester if there’s likely to be a problem. By identifying these high-risk pregnancies early on, we will be able to monitor these women more closely and hopefully help them deliver a healthier baby.” Dr. Gruslin hopes that her studies on IGFBP-4 could lead to new approaches that would improve fetal growth in high-risk pregnancies. This condition, called Fetal Growth Restriction or Intrauterine Growth Restriction, is thought to affect 3%-5% of all pregnancies, and cause close to half of all stillbirths. The study was published on August 1, 2012, in the Journal of Clinical Endocrinology and Metabolism.

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Ottawa Hospital Research Institute