Fetal Scalp Blood Lab Report

Fetal Scalp Blood Sampling-

According to the American College of Obstetricians and Gynecologists11, measurements of the pH in capillary scalp blood may help to identify the fetus in distress.

Procedure of fetal scalp blood sampling-25

After rupture of membranes, an illuminated endoscope is inserted through the dilated cervix and pressed firmly against the fetal scalp. The skin is wiped clean with a cotton swab and coated with a silicone gel to cause the blood to accumulate as discrete globules. An incision is then made through the skin to a depth of 2 mm with a special blade on a long handle. As a drop of blood forms on the surface, it is immediately collected into a heparinized glass capillary tube. The pH of the blood is measured promptly.

There are changes in the T-wave and in the ST segment of the fetal ECG due to a worsening fetal hypoxia. Hence these parameters can be assessed to diagnose a hypoxaemic fetus. A mature fetus exposed to hypoxemia develops an elevated ST segment with a progressive rise in T-wave height that is expressed as T:QRS ratio. An increasing T:QRS ratio indicates fetal cardiac ability to adapt to hypoxia. When hypoxia worsens, it results in an increasingly negative ST-segment deflection such that it appears as a biphasic waveform25. The manufacturer— Neoventa Medical—received FDA (2012) approval for their ST analysis program—the STAN system93 in

Becker97 et al performed a metaanalysis of five randomized trials comprising 15,352 patients and found that use of ST-segment analysis did not reduce the rates of cesarean delivery or fetal metabolic acidemia at birth.

Neilson98 reviewed the Cochrane Database to assess fetal ECG analysis during labor. There were 16,295 women in which such monitoring was performed. It was concluded that fetal ST-segment waveform analysis was useful in preventing fetal acidosis and neonatal encephalopathy when standard fetal heart rate monitoring suggested abnormal patterns.

Intrapartum Doppler Velocimetry-

Doppler analysis of the umbilical artery has been studied as another potential adjunct to conventional fetal monitoring. Abnormal Doppler waveforms may signify pathological umbilical-placental vessel resistance. Farrell99 et al have concluded that this technique is a poor predictor of adverse perinatal outcomes. They concluded that Doppler velocimetry had little role in fetal surveillance during