Talk:Second Trimester: Difference between revisions

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==2015==
==2020==
{{#pmid:31751665}}
'''Morphometric development of the human fetal cerebellum during the early second trimester'''
 
Abstract
The protracted nature of development makes the cerebellum vulnerable to a broad spectrum of pathologic conditions, especially during the early fetal period. This study aims to characterize normal cerebellar growth in human fetuses during the early second trimester. We manually segmented the fetal cerebellum using 7.0-T high-resolution MR images obtained in 35 specimens with gestational ages ranging from 15 to 22 weeks. Volume measurements and shape analysis were performed to quantitatively evaluate global and regional cerebellar growth. The absolute volume of the fetal cerebellum showed a quadratic growth with increasing gestational age, while the pattern of relative volume changes revealed that the cerebellum grew at a greater pace than the cerebrum after 17 gestational weeks. Shape analysis was used to examine the distinctive development of subregions of the cerebellum. The extreme lateral portions of both cerebellar hemispheres showed the lowest rate of growth. The anterior lobe grew faster than most of the posterior lobe. These findings expand our understanding of the early growth pattern of the human cerebellum and could be further used to assess the developmental conditions of the fetal brain.
Copyright © 2019 Elsevier Inc. All rights reserved.
KEYWORDS:
Cerebellum; Fetal brain development; High-resolution MRI; Shape analysis
PMID: 31751665 DOI: 10.1016/j.neuroimage.2019.116372
 


==2014==
==2014==

Latest revision as of 01:12, 21 February 2020

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Cite this page: Hill, M.A. (2024, March 28) Embryology Second Trimester. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/Talk:Second_Trimester


2020

Xu F, Ge X, Shi Y, Zhang Z, Tang Y, Lin X, Teng G, Zang F, Gao N, Liu H, Toga AW & Liu S. (2020). Morphometric development of the human fetal cerebellum during the early second trimester. Neuroimage , 207, 116372. PMID: 31751665 DOI. Morphometric development of the human fetal cerebellum during the early second trimester

Abstract The protracted nature of development makes the cerebellum vulnerable to a broad spectrum of pathologic conditions, especially during the early fetal period. This study aims to characterize normal cerebellar growth in human fetuses during the early second trimester. We manually segmented the fetal cerebellum using 7.0-T high-resolution MR images obtained in 35 specimens with gestational ages ranging from 15 to 22 weeks. Volume measurements and shape analysis were performed to quantitatively evaluate global and regional cerebellar growth. The absolute volume of the fetal cerebellum showed a quadratic growth with increasing gestational age, while the pattern of relative volume changes revealed that the cerebellum grew at a greater pace than the cerebrum after 17 gestational weeks. Shape analysis was used to examine the distinctive development of subregions of the cerebellum. The extreme lateral portions of both cerebellar hemispheres showed the lowest rate of growth. The anterior lobe grew faster than most of the posterior lobe. These findings expand our understanding of the early growth pattern of the human cerebellum and could be further used to assess the developmental conditions of the fetal brain. Copyright © 2019 Elsevier Inc. All rights reserved. KEYWORDS: Cerebellum; Fetal brain development; High-resolution MRI; Shape analysis PMID: 31751665 DOI: 10.1016/j.neuroimage.2019.116372


2014

Second trimester sonographic features of fetal chromosomal defects

Mymensingh Med J. 2014 Apr;23(2):412-6.

Akhter N1, Chakraborty RK.

Abstract

Advances in ultrasound technology have dramatically improved the detection of fetal chromosomal defects. Each chromosomal defect has its own syndromal pattern of detectable abnormalities prenataly. Most commonly detectable defects are Trisomies & Triploidies. Although only an invasive test can provide a definitive diagnosis, fetuses with major chromosomal abnormalities have either external or internal defects that can be recognized by detailed ultrasonographic examination at second trimester. These are defined as ultrasound markers for fetal aneuploidy. This article provides an overview and discussion on prenatal sonographic features that may suggest the presence of a common fetal chromosomal defect.

PMID 24858178

2008

Fetal size in the second trimester is associated with the duration of pregnancy, small fetuses having longer pregnancies

BMC Pregnancy Childbirth. 2008 Jul 16;8:25. doi: 10.1186/1471-2393-8-25.

Johnsen SL1, Wilsgaard T, Rasmussen S, Hanson MA, Godfrey KM, Kiserud T. Author information Abstract BACKGROUND: Conventionally, the pregnancy duration is accepted to be 280-282 days. Fetuses determined by ultrasound biometry to be small in early pregnancy, have an increased risk of premature birth. We speculate that the higher rate of preterm delivery in such small fetuses represents a pathological outcome not applicable to physiological pregnancies. Here we test the hypothesis that in low-risk pregnancies fetal growth (expressed by fetal size in the second trimester) is itself a determinant for pregnancy duration with the slower growing fetuses having a longer pregnancy. METHODS: We analysed duration of gestation data for 541 women who had a spontaneous delivery having previously been recruited to a cross-sectional study of 650 low-risk pregnancies. All had a regular menses and a known date of their last menstrual period (LMP). Subjects were examined using ultrasound to determine fetal head circumference (HC), abdominal circumference (AC) and femur length (FL) at 10-24 weeks of gestation. Length of the pregnancy was calculated from LMP, and birth weights were noted. The effect of fetal size at 10-24 weeks of gestation on pregnancy duration was assessed also when adjusting for the difference between LMP and ultrasound based fetal age. RESULTS: Small fetuses (z-score -2.5) at second trimester ultrasound scan had lower birth weights (p < 0.0001) and longer duration of pregnancy (p < 0.0001) than large fetuses (z-score +2.5): 289.6 days (95%CI 288.0 to 291.1) vs. 276.1 (95%CI 273.6 to 278.4) for HC, 289.0 days (95%CI 287.4 to 290.6) vs. 276.9 days (95%CI 274.4 to 279.2) for AC and 288.3 vs. 277.9 days (95%CI 275.6 to 280.1) for FL. Controlling for the difference between LMP and ultrasound dating (using HC measurement), the effect of fetal size on pregnancy length was reduced to half but was still present for AC and FL (comparing z-score -2.5 with +2.5, 286.6 vs. 280.2 days, p = 0.004, and 286.0 vs. 280.9, p = 0.008, respectively). CONCLUSION: Fetal size in the second trimester is a determinant of birth weight and pregnancy duration, small fetuses having lower birth weights and longer pregnancies (up to 13 days compared with large fetuses). Our results support a concept of individually assigned pregnancy duration according to growth rates rather than imposing a standard of 280-282 days on all pregnancies. PMID 18627638