FIRST LINE SOFTMARKERS IN ROUTINE SCREENING – UNACCEPTABLE HIGH INCIDENCE

Problemstellung: Softmarkers as indicators of chromosomal abnormalities of the fetus are described for more than 15 years now. The main problems of softmarkers are, that they are usually published as sonographic phenomenon in high risk pregnancies prior to amniocentesis. So the positive predictive value is usually overestimated when applied to a screening population. On the other hand, many of those in between almost inumerable softmarkers occur quite often in normal fetuses causing unnecessary anxiety in the mother to be.

Methoden: We evaluated prospectively the occurrence of softmarkers in a medium risk population referred for screening, due to advanced maternal age or suspected fetal anomalies. We differentiated first-line softmarkers, which were looked after in every fetus and second line softmarkers, which were sought after in case of the occurrence of a first –line softmarker or found by chance. All examinations were done by a single operator (M.E.). First and second line softmarkers and their incidence are listed below. Between 8th Sep. 2003 and 31st Aug 2004 2243 fetuses between 15+0 and 29+6 weeks of gestation were examined. Median gestational age was 22 weeks and median maternal age was 32 years (range 14–44 years).

Ergebnisse: Incidence of first line softmarkers: Thickened Nuchal fold 1% (22), Pyelectasis 1,3% (30), Choroid plexus cyst 0,8% (19), Echogenic intracardiac focus 6,2% (140), Single umbilical artery 1,5% (33), Ventricular septal defect 0,7% (15), Echogenic bowel 0,6% (14), Polyhydramnios 1,1% (25), Cerebral ventriculomegaly 1,4% (32), Short femur 1,1% (25), Short humerus 0,8% (19), Elevated ratio Biparietal diameter/ femur length 0,8% (19), brachycephaly 0,7% (15), enlarged cisterna magna 0,0% (1), short nasal bone 2,1% (48).

At least one first line softmarker: 14,9% (334/2243).

Incidence of second-line softmarkers: short middle phalanx Digit V 0,9% (20), more than two renal arteries 2,5% (56), tricuspid regurgitation 2,9% (64), mitral regurgitation 0,1% (2), malalignment of atrioventricular valves 1,2% (26), pericardial effusion 0,4% (10), sandal gap 0,7% (15).

Incidence of at least one second line softmarker: 7,6% (170/2243).

Incidence of at least one first- or second-line softmarker: 19,5% (438/2243)

Schlussfolgerungen: Our data show, that in routine ultrasound screening every fifth pregnant woman will be confronted with some type of softmarker, in the patients perspective an abnormality, which causes anxiety and is hard to understand for the normal patient. Besides focussing on the diagnostic power of additional softmarkers we should focus on regimens and guidelines to handle the problem of softmarkers in everyday routine, where pregnant women are seeking reassurance or hard facts instead of vague propabilities. One strategy could be to ignore second-line softmarkers in otherwise normal fetuses and to use a single softmarker as indication of a thorough examination of the fetus and reevaluation of the individual risk for chromosomal abnormalities before any consequences are taken.