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UMBILICAL BLOOD FLOW INDICES IN PREGNANCIES COMPLICATED BY TYPE 1 DIABETES MELLITUS. Finn Lauszus, Hanne Søndergaard, Carsten Byrialsen, Ervin Kallfa Obstetrical Dept., Herning Hospital, Denmark. What do we do with umbilical indices?.
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UMBILICAL BLOOD FLOW INDICES IN PREGNANCIESCOMPLICATED BY TYPE 1 DIABETES MELLITUS Finn Lauszus, Hanne Søndergaard, Carsten Byrialsen, Ervin Kallfa Obstetrical Dept., Herning Hospital, Denmark
What do we do with umbilical indices? • Estimate symptoms of distress in umbilical arteries, i.e. clinical anticipated risk correspondind to physiological signal of distress • Types of measurements: • ratios between peak systolic velocity (A), • end-diastolic peak velocity (B) and • mean velocity (mean). Most common in clinical practice are pulsatility index (PI = (A - B)/mean), resistant index (RI = (A - B)/A), and S/D ratio (A/B).
What do we know for sure about umbilical indices ?(Evidence group 1, Cochrane Coll.) • We do umbilical blood flow as an indicator for fetal distress and serial measurements are an established tool used for timing of delivery of fetuses with intrauterine growth retardation (IUGR). • However, the latest review is from 1996, stating: ”The use of Doppler ultrasound in high risk pregnancies appears to improve a number of obstetric care outcomes and appears promising in helping to reducing perinatal deaths.”
What did they find? • Doppler ultrasound for fetal assessment in high risk pregnancies by Neilson JP, Alfirevic Z. Cochrane Database of Systematic Reviews 1996, Issue 4. • 11 eligable studies • Less inductions (OR=0.85, p<0.006) • Less perinatal deaths (mainly neonatal) (OR=0.71, p<0.06) • Less hospital admissions (OR=0.61, p<0.0001) • Less cesareans for fetal distress (OR=0.36, p<0.0016) • A new review is under way……
High risk pregnancies… • For most researchers, ‘high risk’ will include maternal diseases like DM, hypertensive disorders, cardiac, renal and autoimmune disorders. All of these conditions are associated with increased perinatal mortality and morbidity • One shortcoming in fetal conditions of high risk is our inability to discern between IUGR, SGA, and fetuses that are constitutionally small with no increased perinatal mortality and mortality
Studies - on T1DM pregnancies • Bracero L 1986 (n=43) Maternal hyperglycemia correlate with S/D ratios • Salvesen DR 1992 (n=14 with nephropathy) Fetuses acidemic and hypoxemic (by amniocenthesis) despite normal umbilical flow values 24 hours before delivery • Zimmermann 1992 (n=53) Vascular resistance declined during the course of pregnancy (measured 3 times range 1-7), no correlation with glycemia • Johnstone FD 1992 (n=128) Abnormal RI is a significant predictor of fetal compromise
T1DM-studies cont’d • Yoon BH 1993 (n=24) A strong relationship between the degree of fetal acidemia and hypercarbia (by cordocentesis) and Doppler velocimetry • Grunewald C 1996 (n=24) Decline in pulsatility indices was absent and not influenced by glycemia (measured two times with one month’s interval) • Wong SF 2003 (n=104) Umbilical artery Doppler velocimetry is not a good predictor of adverse perinatal outcomes in diabetic pregnancies (only 54 had scans within one week of delivery, 4 scans from week 28-38).
Our study • Consecutive, n=129 • Weekly measurement, gestational week 31-36 (total 450), median 4, mean 3.5, range 2-6 • Calculations performed on complete data • Umbilical pH measured in 101 at birth • 77 delivered before week 37 and 8 before week 34, 42 in week 36
The best fitting model According to SPSS
Conclusions • No decrease in umbilical arterial flow indices is seen with progressing gestational age from week 32. • We confirm that newborn of diabetic mothers are more likely to have acidemia and that it is associated with umbilical arterial flow indices.
Strength and weakness • Numbers and consecutive design • Non-randomization, non-blinding • Bias by other (maternal )factors (known or unknown) • Predictive value compared to other variables • If this is standard care what is standard values to aim at? • What are we looking at? Prematurity?