Routine ultrasound screening in diabetic pregnancies.
OBJECTIVE
To assess the detection rate of congenital fetal malformations and specific problems related to routine ultrasound screening in women with pre-existing diabetes.


METHODS
A retrospective study was carried out to assess the performance of routine ultrasound screening in women with pre-existing diabetes (Types 1 and 2) within a tertiary institution. The incidence, type and risk factors for congenital fetal malformations were determined. The detection rate of fetal anomalies for diabetic women was compared with that for the low-risk population. Factors affecting these detection rates were evaluated.


RESULTS
During the study period, 12 169 low-risk pregnant women and 130 women with pre-existing diabetes had routine ultrasound screening performed within the institution. A total of 10 major anomalies (7.7%) and three minor anomalies (2.3%) were present in the fetuses of the diabetic women. Central nervous system and cardiovascular system anomalies accounted for 60% of the major anomalies. Periconceptional hemoglobin A1c of more than 9% was associated with a high prevalence of major anomalies (143/1000). Women who had fetuses with major anomalies had a significantly higher incidence of obesity (78% vs. 37%; P < 0.05). Ultrasound examination of these diabetic pregnancies showed high incidences of suboptimal image quality (37%), incomplete examinations, and repeat examinations (17%). Compared to the 'low-risk' non-diabetic population from the same institution, the relative risk for a major congenital anomaly among the diabetic women was 5.9-fold higher (95% confidence interval, 2.9-11.9). The detection rate for major fetal anomalies was significantly lower for diabetic women (30% vs. 73%; P < 0.01), and the mean body mass index for the diabetic group was significantly higher (29 vs. 23 kg/m2; P < 0.001).


CONCLUSIONS
The incidence of congenital anomalies is higher in diabetic pregnancies. Unfortunately, the detection rate for fetal anomalies by antenatal ultrasound scan was significantly worse than that for the low-risk population. This is likely to be related to the maternal body habitus and unsatisfactory examinations. Methods to overcome these difficulties are discussed.
Wong
S F
SF
Department of Maternal Fetal Medicine, Mater Mothers' Hospital, South Brisbane, Queensland, Australia.
Chan
F Y
FY
Cincotta
R B
RB
Oats
J J N
JJ
McIntyre
H D
HD
D000328:Adult; D000013:Congenital Abnormalities / Q000000981:diagnostic imaging* / Q000453:epidemiology; D003955:Diagnostic Tests, Routine; D005260:Female; D005315:Fetal Diseases / Q000000981:diagnostic imaging*; D006801:Humans; D008403:Mass Screening; D011247:Pregnancy; D011254:Pregnancy in Diabetics / Q000000981:diagnostic imaging*; D016216:Ultrasonography, Prenatal