Faculty Bibliography

BACKGROUND: Low plasma folate concentrations in pregnancy are associated with preterm birth. Here we show an association between preconceptional folate supplementation and the risk of spontaneous preterm birth. METHODS AND FINDINGS: In a cohort of 34,480 low-risk singleton pregnancies enrolled in a study of aneuploidy risk, preconceptional folate supplementation was prospectively recorded in the first trimester of pregnancy. Duration of pregnancy was estimated based on first trimester ultrasound examination. Natural length of pregnancy was defined as gestational age at delivery in pregnancies with no medical or obstetrical complications that may have constituted an indication for delivery. Spontaneous preterm birth was defined as duration of pregnancy between 20 and 37 wk without those complications. The association between preconceptional folate supplementation and the risk of spontaneous preterm birth was evaluated using survival analysis. Comparing to no supplementation, preconceptional folate supplementation for 1 y or longer was associated with a 70% decrease in the risk of spontaneous preterm delivery between 20 and 28 wk (41 [0.27%] versus 4 [0.04%] spontaneous preterm births, respectively; HR 0.22, 95% confidence interval [CI] 0.08-0.61, p = 0.004) and a 50% decrease in the risk of spontaneous preterm delivery between 28 and 32 wk (58 [0.38%] versus 12 [0.18%] preterm birth, respectively; HR 0.45, 95% CI 0.24-0.83, p = 0.010). Adjustment for maternal characteristics age, race, body mass index, education, marital status, smoking, parity, and history of prior preterm birth did not have a material effect on the association between folate supplementation for 1 y or longer and spontaneous preterm birth between 20 and 28, and 28 to 32 wk (adjusted HR 0.31, 95% CI 0.11-0.90, p = 0.031 and 0.53, 0.28-0.99, p = 0.046, respectively). Preconceptional folate supplementation was not significantly associated with the risk of spontaneous preterm birth beyond 32 wk. The association between shorter duration (<1 y) of preconceptional folate supplementation and the risk of spontaneous preterm birth was not significant after adjustment for maternal characteristics. However, the risk of spontaneous preterm birth decreased with the duration of preconceptional folate supplementation (test for trend of survivor functions, p = 0.01) and was the lowest in women who used folate supplementation for 1 y or longer. There was also no significant association with other complications of pregnancy studied after adjustment for maternal characteristics. CONCLUSIONS: Preconceptional folate supplementation is associated with a 50%-70% reduction in the incidence of early spontaneous preterm birth. The risk of early spontaneous preterm birth is inversely proportional to the duration of preconceptional folate supplementation. Preconceptional folate supplementation was specifically related to early spontaneous preterm birth and not associated with other complications of pregnancy

The developmental changes of the fetal central nervous system (CNS) during the second and third trimesters, specifically the brain, relate mostly to changes in size. However, other changes do occur in the fetal brain during the second and third trimester such as: the union of the cerebellar hemispheres, development of the corpus callosum (CC), and increasing complexity of the cerebral cortex. These changes follow a well-defined developmental timeline recognizable by sonography.The fetal neuroscan can be divided into a 'basic scan' which is performed transabdominally and a 'targeted Exam or neurosonogram' which uses a multiplanar approach, which preferably should be performed transvaginally. During the 'basic scan', several brain structures are imaged in addition to obtaining important biometric measurements. The 'neurosonogram' is a more extensive or detailed fetal study during which the emphasis is on the addition of coronal and sagittal planes. The easiest way to obtain these planes, if the fetus is in a cephalic presentation, is the transvaginal route. Three-dimensional (3D) sonography should, if possible, be performed transvaginally using the multiplanar approach. An added benefit of 3D sonography is the ability to display and render the volume in a variety of ways which may enhance the detection of pathology.

Over the past decade, prenatal diagnosis has shifted rapidly from the second trimester into the first trimester. Although the nuchal-translucency scan may detect a small proportion of fetal structural malformations, fetal anatomy is not routinely assessed until the fetal anatomical survey is performed in the second trimester between 18 and 22 weeks. The recent development of high-frequency transvaginal ultrasound transducers has led to vastly improved ultrasound resolution and improved visualization of fetal anatomy earlier in gestation. Several pilot studies of a first-trimester anatomic survey have reported detection rates comparable with those achieved in the routine second-trimester anatomic survey. As advanced ultrasound technology becomes more available, there is an urgent need to evaluate the diagnostic ability of a first-trimester anatomic survey and to determine the role of a first-trimester anatomic survey in the current screening paradigm

OBJECTIVE: Pre-natal ultrasonography presents an opportunity for in-utero therapy of a fetal goiter. Because of the morbidity associated with a large goiter and the risks of repeated intra-amniotic injections, controversy arose about the precise indications of this mode of treatment. We describe our observations in treating a 22-week-old fetus with a large goiter because of dyshormogenesis, monitored with serial 3D high frequency, high resolution ultrasonography and amniotic hormonal measurements. Fetal hypothyroidism was confirmed by cordocentesis and amniotic hormone levels. After assessment of relevant risk factors and the criteria for in-utero intervention, including goiter volume, amniotic fluid index, polyhydramnios and tracheal compression, we determined that hormonal therapy was warranted. Levothyroxine was injected every 7-10 days, and its efficacy monitored by ultrasound changes and amniotic hormone sampling. RESULTS: Reduction in goiter volume restored normal neck flexion relieving the pressure on the trachea, polyhydramnios was prevented and amniotic hormone levels were normalised. The infant was euthyroid at birth, however, by age 4 days hypothyroidism was diagnosed, and treatment with l-thyroxine started. CONCLUSION: Advances in fetal ultrasonography permit judicious therapy of an enlarging goiter in a hypothyroid fetus, which may contribute to enhancing cognitive development. We discuss the value of amniotic hormone sampling, the objectives and risks of in-utero intervention in the light of recent literature and our own observations

Imaging the fallopian tube with transvaginal sonography is a daunting task for any sonologist. High-frequency ultrasound transducers, the advancement of color and power Doppler, as well as 3D surface rendering, have advanced the assessment of fallopian tubes in healthy and pathologic states. This review focuses on fallopian tube anatomy, imaging modalities available for its assessment and common pathologic processes, including infection/inflammation, ectopic pregnancy, salpingitis isthmica nodosum, tubal torsion and prolapse, and fallopian tube carcinoma. The natural history of pelvic inflammatory disease is discussed in detail with a sonographic representation of the disease process. 2009 Expert Reviews Ltd