Trophoblastic volumetric bloodflow evaluation in women with trombophylia on 7–10th week of pregnancy
Authors: Asriyants M. A. , Astafieva O. V. 
Published: September 2021

Spontaneous abortion occur in 15–20% of all detected pregnancies, and 45–70% of all spontaneous miscarriages take place up to 10 weeks. Thrombophilia is one of the main causes of miscarriage and its effect on the course of pregnancy remains poorly understood. In this regard, there is great interest in the problem of diagnosing thrombophilia and further prevention of thrombosis in obstetric practice.

Purpose. Compare the parameters of volumetric blood flow in the chorion with different types of trophoblastic blood flow disturbance in pregnant women with thrombophilia in the first trimester for their quantitative verification.

Materials and methods. The study included 129 pregnant women at the 7th to 10th week of gestation with a diagnosis of thrombophilia and a control group - pregnant women with a normal course of this pregnancy and a successful outcome of past pregnancies.

The patients were divided into III clinical groups:

I. Pregnant women with a normal course of this pregnancy and a successful outcome of past pregnancies (n = 33) – comparison group;

II. Pregnant women with thrombophilia, in whom current pregnancy occurred on anticoagulant therapy (n = 28);

III. Pregnant women with thrombophilia without taking anticoagulant drugs before registration of pregnancy (n = 68).

Ultrasound was performed on Voluson E8 and S8 machines. All pregnant women underwent transabdominal and transvaginal ultrasound in B-mode, in color-doppler (CD) mode, and volumetric reconstruction of chorion was performed using the VOCAL program. In B-mode, the state of the embryo and extraembryonic structures were examined. The identification of trophoblastic vessels was carried out using the CD – region of interest was placed in the trophoblast area detected in B-mode, size and shape was adapted for a particular section.

Using three-dimensional echography, the chorion volume was performed. The degree of blood supply in chorionic volume were calculated; vascularization index (VI), flow index (FI) and perfusion index (VFI) were displayed on a histogram with quantitative indicators.

Results

In the CD mode, the types of trophoblastic blood flow were identified in the chorionic vessels:

1) continuous type – blood flow loci are continuously identified over the entire area of the basal surface of the trophoblast;

2) intermittent type – blood flow loci are unevenly identified along the basal surface of the trophoblast;

3) single loci – single blood flow loci are identified along the basal surface of the trophoblast;

4) lack of blood flow – blood flow loci are not determined along the basal surface of the trophoblast.

Assessment of the quantitative parameters of the volumetric blood flow was used in the corresponding type of blood flow to verify the classification of types of trophoblastic blood flow in the CD mode.

Statistical analysis of the volumetric blood flow indices using three-dimensional chorionic reconstruction showed a high degree of reliability (p < 0.0001) in the VI and VFI values between all corresponding types of blood flow.

Discussion. High incidence of spontaneous abortion and the significant role of thrombophilia in this pathology leads to necessity of expanding the research in this area. There has been a lot of research done over the past decade. The quantitative threshold values of the resistance indices in the chorionic vessels were calculated using pulse-wave Doppler, the chorionic blood supply indices were determined using volumetric reconstruction for various pathologies.

However, we have not previously met the classification of chorionic blood supply in the CD mode. This technique is very simple to perform and is a highly informative for predicting miscarriage in the first trimester. For the first time, we proposed the above classification of trophoblastic blood flow; for the first time, we proved the reliability of the classification developed by us using the method of volumetric reconstruction of the chorion with an assessment of trophoblastic blood flow, which allows us to recommend its use when writing a protocol for ultrasound of the fetus in the first trimester in pregnant women with thrombophilia.

Conclusion. The classification of trophoblastic blood flow was verified by three-dimensional echography with quantitative indicators of the volumetric blood flow of the trophoblast vessels, with a high degree of reliability (p < 0.001) which to indicates the reliability of this classification. It can be recommended to conduct a multicenter study for investigating fetal ultrasound with the additional use of the CD in the first trimester in pregnant women with a diagnosis of thrombophilia.