Doppler sonography of uterine arteries at 20-23 weeks: depth of notch gives information on probability of adverse pregnancy outcome and degree of fetal growth restriction in a low-risk population.

OBJECTIVE: Our purpose was to assess the relation between the depth of notch in the uterine arteries at 20-23 weeks and the incidence and severity of subsequent pregnancy complications. METHODS: The Notch Index (NI) was defined as (C - D)/C, with C = postsystolic zenith and D = postsystolic nadir. For evaluation, the mean NI of the two uterine arteries was determined. Adverse pregnancy outcome was defined as presence of SGA < or =5th percentile, pre-eclampsia, preterm delivery <33 weeks, placental abruption or intrauterine or neonatal death. Women who received preventive treatment (Aspirin or low-molecular heparin) were excluded. RESULTS: A notch was present in 957 of 15,888 singleton pregnancies (6.0%; unilateral = 4.37%, bilateral = 1.66%). The incidence of adverse pregnancy outcome was 5.3%; it increased from 4.6% for women without notch to 41.8% for those with a mean NI > or =0.2 and higher. Moreover, higher mean NI values tended to be associated with lower birth weight. In addition to the maternal age, parity, mean Pulsatility Index and presence of notch, the depth of notch made an additional significant contribution to the assessment of the probability of adverse pregnancy outcome. CONCLUSION: Besides the classic parameters such as maternal age, history of adverse pregnancy outcome, parity, impedance and the presence of notch, also the depth of notch seems to be valuable in the assessment of adverse pregnancy outcome risk. Especially in cases where very high or very low values of NI are measured, quantification of the depth of notch may give more information than the description of the presence of notch alone. This might be of value for future multivariate models for risk assessment of adverse pregnancy outcome.

Doppler sonography of uterine arteries at 20-23 weeks: risk assessment of adverse pregnancy outcome by quantification of impedance and notch.

OBJECTIVE: To assess the diagnostic value of Doppler sonography of the uterine arteries (DSUA) at 20-23 gestational weeks as screening procedure in a low risk population. PATIENTS AND METHODS: The study group consisted of 7508 singleton low-risk pregnancies. Doppler sonography of both uterine arteries was performed as routine part of anomaly scan. Impedance of both uterine arteries was registered using the mean PI of the two uterine arteries. In case of notch, "Notch-Index" was defined as (C-D)/C with D = post-systolic nadir and C = following zenith of the waveform. Outcome variables were placental abruption, pre-eclampsia, intrauterine growth retardation, intrauterine/neonatal death and preterm delivery before 32 completed gestational weeks. To discriminate normal and pathological waveform, incidence of adverse pregnancy outcome was related to four different definitions of pathological waveform. To describe the severity of impairment of perfusion, the frequency of adverse pregnancy outcome was related to different classes of impedance. RESULTS: To find a simple discrimination between normal and pathological uterine perfusion, best diagnostic performance was reached by a definition using a combination of high impedance and notch (no notch and mean PI > P'95 or unilateral notch and mean PI > P'90 or bilateral notch and mean PI > P'50). The prevalence of notch in nulliparae (8.5%) was higher than in parae (4.7%) and decreased with increasing gestational age (20 weeks: 8.6%-23 weeks: 5.4%). We found a clear relation between elevation of impedance, depth of notch and frequency of adverse pregnancy outcome with a frequency of complications varying from 3.2% (mean PI < or = 0.8, mean NI = 0.1) to 38.4% (mean PI > 2.0, mean NI > 0.1). CONCLUSION: Doppler sonography of the uterine arteries at 20-23 weeks has the capacity to predict at least a part of severe forms of adverse pregnancy outcome and to assess the probability of complications by quantification of the impairment of the uterine blood flow.