The impact of maternal obesity on midtrimester sonographic visualization of fetal cardiac and craniospinal structures

Abstract

OBJECTIVE:To examine the impact of maternal obesity on the rate of suboptimal ultrasound visualization (SUV) of fetal anatomy and determine the optimal timing of prenatal ultrasound examination for the obese gravida. METHODS: A computerized ultrasound database was used to identify ultrasound examinations for singleton gestations performed between 14 0/7 and 23 6/7 weeks at a tertiary care, university-based hospital. Patients were divided into four groups and categorized based on body mass index (BMI): nonobese (BMI o30 kg/m 2 ), class I obesity (30rBMIo35 kg/m 2 ), class II obesity (35rBMIo40 kg/m 2 ), and extreme obesity (BMI Z40 kg/m 2 ). The rates of SUV for fetal cardiac and craniospinal structures were calculated for each group and compared. RESULTS: A total of 11 019 pregnancies were studied, of which 38.6% of the patients were obese. Overall, the rate of SUV of the fetal structures was higher for obese compared to nonobese women for both cardiac (37. With increasing gestational age at examination, the rate of SUV decreased for both obese and nonobese women. However, for obese women there was minimal improvement in visualization after 18-20 weeks. Even after adjustment for gestational age and the type of ultrasound machine, obese women (class I, class II, and extreme obesity) were still associated with increased odds for SUV of the fetal cardiac and craniospinal structures compared to nonobese women. CONCLUSION: Maternal obesity increases the rate of SUV for the fetal cardiac structures by 49.8% and for the craniospinal structures by 31%. The optimal gestational age for visualization of fetal cardiac and craniospinal anatomy in obese patients may be after 18-20 weeks.

Pregnancy termination following prenatal diagnosis of anencephaly or spina bifida: A systematic review of the literature

“…As an example, ultrasound visualization of the fetal anatomy and prenatal diagnosis of birth defects is more difficult in obese mothers than normal weight mothers (Hendler et al, 2004;Dashe et al, 2009). If the ultrasound examination must be repeated later in pregnancy to complete the fetal anatomic examination or if an accurate diagnosis cannot be made, obese mothers might have on average a later gestational age at prenatal diagnosis than non-obese mothers and therefore be less likely to be able to consider a TOP (Hendler et al, 2004;Phatak and Ramsay, 2010). As a result, non-obese mothers might be more likely to have a TOP than obese mothers and cases of NTDs among nonobese mothers might be missed, creating a potentially spurious association between prepregnancy obesity and NTDs.…”

Obstetrical sonography in obese women: A review

“…The overall visualization of fetal organs with respect to F o r P e e r R e v i e w Obstetrical ultrasound and obesity increasing maternal size has been previously addressed by several studies 38,39 . Reduction in successful image generation was most marked for cardiac and cerebrospinal structures as well as the umbilical cord 40,41 . Catanzarite et al postulated five categories of potential barriers to complete fetal anatomic survey.…”

“…They found a degradation in image quality by 10 % for every further step in obesity classification 41 .…”

Feasibility of fetal cardiac magnetic resonance imaging: preliminary experience

“…Unlike ultrasound imaging, this modality is not affected by maternal and fetal conditions such as obesity 7 and oligohydramnios 8 , which particularly impair sonographic visualization of the fetal heart; maternal obesity increases the rate of sub-optimal ultrasound visualization of the fetal cardiac structures by 49.8% 7 , despite advanced ultrasound equipment 9 . We retrospectively (and arbitrarily) selected 10 of 69 patients (c. 14%) who had undergone fetal chest or urinary tract MRI during a 12-month period (April 2005 to April 2006).…”