Is there a good time for nuchal translucency measurement?

Abstract

A combined screening for Down syndrome and other aneuploidies can be offered to pregnant women between 11 +0 and 13 +6 weeks of gestation. It includes ultrasound evaluation of nuchal translucency (NT) and maternal plasma assay of f-βhCG and PAPP-A (Bindra et al., 2002;Nicolaides 2003Nicolaides , 2005. The technique of NT measurement should follow exact criteria: the sonographer should obtain an image of the fetal head, neck and upper part of the thorax and should enlarge it as much as 3/4 of the screen. To avoid over-or underestimating NT thickness, the fetus should be in a neutral position, neither too extended nor flexed. It is very important to distinguish fetal skin from the amniotic membrane and this can be obtained by waiting for the fetus to move spontaneously or by gently pressing on maternal abdomen (Pandya et al., 1995;Nicolaides et al., 1998;Evans et al., 2007).Active fetal movements are one of the factors that can help the operator to acquire rapidly the best view for NT assessment. We hypothesize that fetal movement may be related to the fetal metabolic status.Glucose, which passes from the maternal compartment through the placenta by direct diffusion, represents the most important metabolic substrate for the fetus, and it is totally dependent on maternal glycemia (Weissgerber and Wolte, 2006). The circadian glycemic profile in normal pregnant women is characterized by postprandial prolonged hyperglycemia (facilitated anabolism) that permits transfer of glucose to the fetus despite the mother's intermitting feeding (Herrera, 2002). Glycemic mean levels during the day are similar to nonpregnant condition as hyperglycemic postprandial periods are counterbalanced by hypoglycemic ones far away from the meals (Yogeu et al., 2004).Because we had the impression that NT thickness assessment was faster when done early in the morning than later, we hypothesized that maternal glucose intake may affect time for NT measurement.We enrolled a total of 220 women with singleton pregnancy booked for first trimester screening for Down syndrome and other aneuploidies from

The Fundamentals of Fetal MR Imaging: Part 1

“…41 Maternal fasting has been suggested before the procedure to reduce both maternal bowel peristalsis and fetal movement. 2 Although there is evidence that a recent maternal meal can increase fetal movements, 42 in our experience, having the mother fast has not had a significant effect on imaging quality and is not routinely requested. However, we do request that the mother abstain from caffeine and other stimulants on the day of the examination.…”

Canadian Association of Radiologists Recommendations for the Safe Use of MRI During Pregnancy

“…59 This is supported by one ultrasound study that found active fetal movements during the first and third hours after food intake. 60 However, in a prospective survey study of 228 mothers, Yen et al recently reported no relationship between intake of high glucose or caffeinated beverages with fetal motion on MRI. 61 Ultimately, based on the limited data available, the use of sedatives and/or fasting does not appear to be necessary in most routine cases.…”