Correlation between uterine artery blood flow and three dimensional ultrasound assessment of gestational sac volume (GSV)‎ in the first trimester : Normal and missed abortion cases

Abstract EN

First trimester amniotic fluid is an ultra-filtrate of maternal plasma and constitutes the major component of Gestational Sac Volume (GSV).

GSV may reflect function of early utero-placental unit and therefore provide basis for predicting pregnancy outcome.

The main objective of this study is to assess 3D GSV and Uterine Artery (UA) Doppler indices in missed abortion and normal pregnancy and to correlate between them in both groups Two groups were selected: Study group ( 32 cases of missed abortion in 1st trimester) and Control group (50cases with normal 1st trimester pregnancy).

Both groups were characterized by having singleton pregnancy, with gestational age (6-12 weeks menstrual weeks) and sure date of the last menstrual period.

They were subjected to: Trans Vaginal Ultrasound (TVUS) examination with 2D mode to measure Crown Rump Length (CRL), Mean Gestational Sac Diameter (MGSD), internal cervical so (IO), presence or absence of fetal cardiac pulsations, evaluation of Yolk Sac (YS) and placental site in both groups.

Uterine artery Doppler (UA Doppler) wave-form was obtained on both sides using color Doppler mode then Resistance index (RI), systolic / diastolic (S / D) ratio, and plasticity index (PI) were automatically calculated by the machine.

3D scan for the pregnancy sac was done using TV volume probe 7.5 MHz (Sono Ace 9900, Medison).

The 2 groups were compared as regards CRL, GA, GSV, and Doppler indices.

Relation between these variables in each group was investigated. Gestational age (in days) was significantly higher in missed abortion than control group (71.34 ± 15.88 versus 62.04 ± 15.72 days, P = 0.013).

CRL was significantly higher in missed abortion than control group 28.25 ± 16.7 versus 20.04 ± 15.3 = mm, (P 0.012 GSV was insignificantly lower in missed abortion than control (27.76 ± 28.8 versus 28.38 ± 25.05 ml, P = 0.93).

The three uterine artery Doppler indices RI, PI, and S / D ratio were insignificantly higher in missed abortion than control.

Correlation between gestational age, CRL and GSV on one hand and uterine artery Doppler indices on the other hand, revealed only significant positive correlation between CRL and GSV in normal pregnancy and missed abortion.

No correlation was found between CRL, uterine artery Doppler indices in both groups.

Also no correlation was found between GSV and uterine artery Doppler indices in both groups.

We can conclude that 3D TVUS can give accurate and rapid measurement of GSV.

Gestational sac volume below the normal for age may predict 1st trimester pregnancy loss in complicated first trimester pregnancy.

Uterine artery Doppler indices may not reflect the actual role of uterine artery flow in GSV determination.

Uterine artery Doppler indices as predictor for pregnancy outcome have to be validated using larger number of cases at risk for abortion.