Umbilical cord blood flow

Introduction Checking the umbilical blood flow is to determine the development of the fetus in the uterus, such as the presence of intrauterine growth retardation, to determine whether there is a tendency to develop hypertensive syndrome in pregnancy, to determine whether there is intrauterine hypoxia, fetal chromosomal abnormalities Umbilical blood flow such as congenital malformation can sometimes show abnormalities. Abnormal umbilical blood flow may also be associated with developmental defects in the placenta, histological abnormalities. The normal value is related to the number of weeks of pregnancy.

Cause

Abnormal umbilical blood flow may be associated with hypertensive syndrome of pregnancy, intrauterine hypoxia or fetal chromosomal abnormalities, developmental defects of the placenta, and histological abnormalities.

an examination

Related inspection

Bleeding time blood routine

The normal value is related to the number of weeks of pregnancy. There are three main items, the S/D value is the main indicator, and the S/D value in the late pregnancy is less than or equal to 3.0 as the normal value. The umbilical blood flow has a close relationship with the gestational age. Generally, with the increase of gestational age, the umbilical blood flow shows a downward trend. The normal value of umbilical blood flow is 3.5 at 24 weeks, and the upper limit is 4.25, which is abnormal.

Differential diagnosis

Umbilical cord blood flow examination needs to be identified as follows.

The first stage: If the S/D and RI values increase during the 26th to 28th week of pregnancy (S/D should be less than 3 after 28 weeks, RI should be less than 0.8), the main consideration should be:

(1) Fetal malformation: fetal congenital disease is closely related to umbilical artery resistance, and should be further examined by B-ultrasound.

(2) Umbilical cord abnormality: When the umbilical cord is entangled, too long or too short, and too fine to affect the placental circulation, the abnormality is the blood flow impedance index. If the S/D value is higher than the normal value, and the B-ultrasound shows abnormal conditions such as the umbilical cord around the neck, it should be closely observed according to the stage of pregnancy.

(3) Placental dysfunction: The pathological changes of the placenta can reduce the volume of the placenta, reduce the total cross-sectional area of the effective blood vessels, increase the blood flow resistance, and reduce the blood perfusion.

(4) Intrauterine growth retardation (IUGR): There are many reasons for the occurrence of IUGR in pregnant women. In addition to factors such as genetic nutrition, harmful contact, malformation, and viruses, the proportion of IUGR due to pregnancy accessories such as placenta is increasing. , the performance of S / D, RI increased.

The second stage: after 36 to 37 weeks of monitoring, the umbilical artery blood flow impedance is divided into three levels:

Grade 1: S/D value <3.0, umbilical artery blood flow impedance is at a normal level.

Level 2: S/D value >3.0, but <4.0, will not cause acute fetal distress, should be treated in time to prevent the disease from worsening.

Level 3: S/D values > 4.0, which will lead to poor prognosis in perinatal.

The third stage: umbilical artery impedance index during childbirth:

There was no significant change in the S/D value during normal pregnancy in pregnant women. If the index is abnormal, the prognosis of perinatal is poor.

If the diagnosis is abnormal for umbilical blood flow, it is best to monitor the fetal condition several times per day. If the abnormality of the umbilical blood flow is not very serious, it is recommended to take the left lateral position. If it does not improve, oxygen therapy is needed if necessary.

The material in this site is intended to be of general informational use and is not intended to constitute medical advice, probable diagnosis, or recommended treatments.