Clinical Trial: Identification of Early Predictors of Fetomaternal Hemorrhage

Study Status: Completed
Recruit Status: Completed
Study Type: Observational

Official Title: Identification of Early Predictors of Fetomaternal Hemorrhage And Development Of An Automated Screening Strategy For At-Risk Pregnancies

Brief Summary:

Objectives: 1) To determine risk factors for fetomaternal hemorrhage. 2) To identify a cost-effective method to detect fetomaternal hemorrhage prior to significant fetal anemia.

Significance/Background: Fetomaternal hemorrhage (FMH) is a condition in which occurs when the placenta transfers blood from the fetus to the mother. Normally, nutrition and gasses pass from mother to baby through the placenta and only waste products pass from baby to mother through the placenta. Whole blood cells do not normally cross the placenta in significant amounts. Mild FMH, where a small amount of whole blood passes from fetus to mother but does not hurt the mother or baby, occurs in about 75% of pregnancies. A pregnant woman does not know this occurs. It is only discovered if a special blood test that is labor-intensive to perform and difficult to interpret called the Kleihauer-Betke acid elution test is done. As mild FMH hurts no one, this test is not part of routine care. In most cases, testing is done only if a baby is born sick with unexplained anemia. Severe FMH, which can cause the baby to become sick from anemia (low red blood cell count) is caused by large blood loss into the mother, occurs in only 1-3 per 1000 births. Severe anemia caused by FMH can result in death of the baby before or after birth, or significant illness in the newborn period. Short term problems for the baby include difficulty breathing, difficulty maintaining blood pressure, and difficulty providing oxygen to all parts of the body. This can cause multiple problems with the function of internal organs including the liver, kidneys, intestines, and brain. Babies who become sick from severe FMH can develop long-term problems including cerebral palsy (a lifelong problem with body movements) and/or mental retardation.

It is not known why some pregnancies are affected

Detailed Summary:

1. Introduction:

   The objective of this study is to identify candidate clinical predictors of fetomaternal hemorrhage (FMH) and to devise a screening strategy to identify pregnancies affected by the condition before the fetus is compromised by severe anemia.

   Fetomaternal hemorrhage is a condition in which the placental barrier fails and the fetus "bleeds" into the maternal circulation. When functioning correctly, the placenta allows transfer of nutrients and waste between the mother and fetus while keeping the cellular components of blood separate. It is not uncommon for small amounts of fetal blood to reach the maternal circulation without adverse effect on the fetus. In fact, mild FMH can be detected in up to 75% of normal pregnancies. In approximately 3 in 1000 pregnancies, however, the volume of fetal blood transferred to the mother causes clinically-significant anemia in the fetus. Fetal anemia can cause significant morbidity and mortality. In fetuses who survive severe anemia, life-long disability is common.

   Diagnosis of FMH is most commonly made after an adverse fetal or neonatal outcome has occurred, indicating the need for testing. Early risk factors for FMH are unknown. Clinical predictors of FMH have been suggested, but have not been born out in retrospective study. Current standard of care testing for FMH, the Kleihauer-Betke (KB) acid elution test, is labor-intensive and time-consuming, and therefore expensive. Additionally, the KB test is observer-dependent and can be significantly affected by variations in sample preparation. No screening protocol for FMH with automated laboratory testing appropriate for use in the general pregnant population exists.

   Blood drawn in conjunction with the mandated New York State Newborn Screening Program specimen