[Uteroplacental haemodynamics and uterine artery Doppler practice at 12 weeks gestation]

Comparison of two different sites of measurement for transabdominal uterine artery Doppler velocimetry at 11-13 weeks

OBJECTIVES

To compare the feasibility of two transabdominal approaches for performing first-trimester uterine artery (UtA) Doppler and to evaluate the correlation with pulsatility index (PI) in the second trimester.

METHODS

This was a prospective longitudinal Doppler study of the uterine arteries at 11-13 and 21-22 weeks' gestation. Transabdominal ultrasound and color Doppler were used to measure the UtA-PI of the ascending branch of the uterine artery at the level of the internal cervical os (Site A) and at the level of the apparent crossover with the external iliac artery (Site B) at 11-13 weeks, and at Site B only at 21-22 weeks. In all cases the measured left and right PI were converted to a multiple of the median (MoM) for gestational age, and the intercorrelation between the measurements at different sites and gestational ages was calculated using non-parametric analysis (Spearman's rank correlation).

RESULTS

Satisfactory measurements were obtained at 11-13 weeks from both uterine arteries in all 81 women at Site A and in 50 (62%; 95% CI, 50-72%) at Site B (P < 0.01). Measurements were obtained at Site B at 21-22 weeks in all cases. In the 50 cases with measurements from both sites at 11-13 weeks, the correlation of PI-MoMs between Sites A and B at 11-13 weeks was only moderate (ρ = 0.61). The correlation between first-trimester UtA-PI MoMs at Site A and second-trimester UtA-PI MoMs was stronger than that between first-trimester UtA-PI MoMs at Site B and second-trimester UtA-PI MoMs (ρ = 0.73 vs ρ = 0.47, P < 0.01).

CONCLUSION

Evaluation of UtA-PI at 11-13 weeks can be achieved at the level of the internal cervical os in a greater proportion of women than at the level of the apparent crossover with the external iliac vessels, and the measurements obtained correlate better with second-trimester UtA-PI.

The significance of uterine notching in Doppler sonography in early pregnancy as a predictor for pathologic outcome of the pregnancy

INTRODUCTION

Doppler sonography of maternal vessels as a predictor for preeclampsia is an established screening method in the second trimester. Considering the first trimester its benefit has not been conclusively proven so far. Up to now the flow pattern of maternal vessels in the first trimester has only been insufficiently characterized and documented. Thus, there are only few pieces of information concerning the predictive value of the different kinds of flow patterns during the early pregnancy as regards the pathological and physiological outcome of the pregnancy. This survey aimed at evaluating the significance and the clinical importance of Doppler sonographical examinations of the Aa. uterinae during early pregnancy. It had to be analyzed whether various perfusions can be applied as a predictive value for the specific development during the pregnancy and whether therefore a risk group for pregnancy-associated hypertension can already be detected during the early pregnancy.

MATERIALS AND METHODS

A non-selected collective of 104 pregnant patients was examined with Doppler sonography and retrospectively divided into a standard collective and a high-risk collective. The standard collective contained 89 patients, who in the course of their pregnancy remained without any pathological findings. Fifteen patients, who were assigned to the high-risk collective, either developed a pregnancy-induced hypertension during their pregnancy or an intrauterine fetal growth retardation. The Doppler-sonographic examination of the Aa. uterinae was applied for the first time between the 6 and 8 weeks gestation (WG), then in the 9 WG, 10 WG, 11 WG, between the 12 and 14 WG, as well as between the 20 and 24 WG.

RESULTS

Contrary to published data, there can be traced a completely transformed flow pattern in the Aa. uterinae already during the first trimester to an increasing extent. This correlates with a positive outcome of the pregnancy. There is a definite association between pathological Doppler sonography in the first third of the pregnancy and the development of a uteroplacental insufficiency as well as a pregnancy-associated hypertension (SIH) in the further course of the pregnancy.

CONCLUSION

Doppler sonography is an approved method in order to become early attentive of a reduced uterine blood flow. Applying Doppler sonographic treatment of the maternal vessels, uteroplacental insufficiency can be traced at an early stage. Pregnancies, which might develop a pregnancy-associated hypertension (SIH) or a placental insufficiency, can be detected during the early pregnancy to decrease the morbidity rate and the mortality of premature newborns. Further studies in larger collectives are necessary to obtain adequate solid datasets and to further evaluate the clinical meaning and the significance concerning pathological maternal Doppler parameters.