[Qualitative blood flow parameters in the spiral artery and progesterone concentration in pregnancy complicated by threatened abortion].

Objectives: The aim of the study was to determine the values of i.e. resistance index (RI) and pulsatility index (PI) in the spiral arteries and to evaluate the maternal serum concentration of progesterone trying to find correlation between these parameters in the group of patients in early pregnancy complicated by threatened abortion.
Study Methods: We have analysed 30 pregnant women between 5th and 12th weeks of pregnancy with the symptoms of vaginal bleeding & lower abdominal pains diagnosed as threatened abortion. In all patients transvaginal ultrasound examination with pulse color Doppler was performed. The RI and PI values were calculated for blood flow velocity waveforms obtained from the spiral arteries. The concentration of progesterone in maternal serum was evaluated by Microparticle Enzyme Immunoassay. The correlation between analysed parameters and pregnancy duration was examined with use of linear correlation by Pearson. The correlation between Doppler and biochemical parameters were analysed with use of rang correlation method by Spearman.
Results: Thirty flow velocity waveforms from spiral arteries were analysed and blood flow indices were calculated. We have found statistically significant negative correlation between the values of both blood flow parameters (RI & PI) and successive weeks of pregnancy (p < 0.001) and statistically significant positive correlation between maternal serum concentration of progesterone and pregnancy duration (p < 0.05). In the tested group in 40% of patients the level of progesterone was abnormal. We have not find any correlation between serum progesterone concentration and doppler parameters in our study.
Conclusions: There is observed the characteristic drop of resistance to the blood flow in the vessels of the uteroplacental circulation in the successive weeks of early pregnancy in patients with threatened abortion similar to normal early pregnancies. Lack of correlation between maternal serum concentration of progesterone and blood flow parameters indicates that other hormonal factors play major role in the regulation of the blood flow in these vessels in early pregnancy. Only the combination of Doppler blood flow analysis in spiral arteries and progesterone evaluation in the maternal serum performed in first trimester may be useful for the intensive fetal monitoring of high risk pregnancies.