Talk:Third Trimester

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Cite this page: Hill, M.A. (2021, May 7) Embryology Third Trimester. Retrieved from


He LX, Wan L, Xiang W, Li JM, Pan AH & Lu DH. (2020). Synaptic development of layer V pyramidal neurons in the prenatal human prefrontal neocortex: a Neurolucida-aided Golgi study. Neural Regen Res , 15, 1490-1495. PMID: 31997813 DOI. Synaptic development of layer V pyramidal neurons in the prenatal human prefrontal neocortex: a Neurolucida-aided Golgi study.

Abstract The prefrontal neocortex is involved in many high cognitive functions in humans. Deficits in neuronal and neurocircuitry development in this part of the cerebrum have been associated with various neuropsychiatric disorders in adolescents and adults. There are currently little available data regarding prenatal dendrite and spine formation on projecting neurons in the human prefrontal neocortex. Previous studies have demonstrated that Golgi silver staining can identify neurons in the frontal lobe and visual cortex in human embryos. In the present study, five fetal brains, at 19, 20, 26, 35, and 38 gestational weeks, were obtained via the body donation program at Xiangya School of Medicine, Central South University, China. Golgi-stained pyramidal neurons in layer V of Brodmann area 46 in fetuses were quantitatively analyzed using the Neurolucida morphometry system. Results revealed that somal size, total dendritic length, and branching points of these neurons increased from 26 to 38 gestational weeks. There was also a large increase in dendritic spines from 35 to 38 gestational weeks. These findings indicate that, in the human prefrontal neocortex, dendritic growth in layer V pyramidal neurons occurs rapidly during the third trimester of gestation. The use of human fetal brain tissue was approved by the Animal Ethics Committee of Xiangya School of Medicine, Central South University, China (approval No. 2011-045) on April 5, 2011. KEYWORDS: Golgi staining; Neurolucida; human brain banking; neurodevelopment; neuropsychiatric disorders; prefrontal cortex; synaptogenesis; three-dimensional reconstruction PMID: 31997813 DOI: 10.4103/1673-5374.274345


Quantitative Folding Pattern Analysis of Early Primary Sulci in Human Fetuses with Brain Abnormalities

AJNR Am J Neuroradiol. 2017 May 18. doi: 10.3174/ajnr.A5217. [Epub ahead of print]

Im K1, Guimaraes A2, Kim Y2, Cottrill E2, Gagoski B2, Rollins C2, Ortinau C2, Yang E2, Grant PE2.


BACKGROUND AND PURPOSE: Aberrant gyral folding is a key feature in the diagnosis of many cerebral malformations. However, in fetal life, it is particularly challenging to confidently diagnose aberrant folding because of the rapid spatiotemporal changes of gyral development. Currently, there is no resource to measure how an individual fetal brain compares with normal spatiotemporal variations. In this study, we assessed the potential for automatic analysis of early sulcal patterns to detect individual fetal brains with cerebral abnormalities. MATERIALS AND METHODS: Triplane MR images were aligned to create a motion-corrected volume for each individual fetal brain, and cortical plate surfaces were extracted. Sulcal basins were automatically identified on the cortical plate surface and compared with a combined set generated from 9 normal fetal brain templates. Sulcal pattern similarities to the templates were quantified by using multivariate geometric features and intersulcal relationships for 14 normal fetal brains and 5 fetal brains that were proved to be abnormal on postnatal MR imaging. Results were compared with the gyrification index. RESULTS: Significantly reduced sulcal pattern similarities to normal templates were found in all abnormal individual fetuses compared with normal fetuses (mean similarity [normal, abnormal], left: 0.818, 0.752; P < .001; right: 0.810, 0.753; P < .01). Altered location and depth patterns of sulcal basins were the primary distinguishing features. The gyrification index was not significantly different between the normal and abnormal groups. CONCLUSIONS: Automated analysis of interrelated patterning of early primary sulci could outperform the traditional gyrification index and has the potential to quantitatively detect individual fetuses with emerging abnormal sulcal patterns. © 2017 American Society of Neuroradiology.

PMID 28522661 DOI: 10.3174/ajnr.A5217


Impact of maternal characteristics on fetal growth in the third trimester of pregnancy. A population-based study

Ultrasound Obstet Gynecol. 2012 Feb 3. doi: 10.1002/uog.11125. [Epub ahead of print]

Lindell G, Maršál K, Källén K. Source Department of Obstetrics and Gynecology, Clinical Sciences Lund, Lund University, Lund, Sweden.


Objectives. To investigate the association between maternal characteristics and fetal growth during the third trimester of pregnancy. Methods. Using a population-based perinatal register, 48,809 term singleton pregnancies were identified for which a routine ultrasound examination in the third trimester was performed between 1995 and 2009. Fetal and infant weight, respectively, were expressed as gestational age specific standard deviation scores (z-scores) using a Swedish ultrasound-based reference curve. The growth of each fetus was assessed using the difference between the birth weight z-score and the fetal weight z-score estimated at the ultrasound examination, adjusted for gestational age, and divided by the time elapsed between the ultrasound examination and birth. Analyses were performed using multivariate linear and polynomial regression analyses. Results. Positive associations were found between maternal body mass index (BMI), height, preexisting diabetes mellitus, and a high fetal growth, whereas maternal smoking had a negative impact. In the univariate analyses, primiparity and grand multiparity (≥4 previous children) were significantly associated with a reduced fetal growth, but in the multivariate analysis, no association between parity and fetal growth could be detected. Both the univariate and the multivariate analyses revealed a significant inverse u-shaped association between maternal age and fetal growth. Conclusions. Fetal third trimester growth was positively associated with increasing maternal BMI, height, and pre-existing diabetes mellitus, and was negatively associated with maternal smoking. No significant association between fetal growth and maternal parity or gestational diabetes mellitus was detected when adjustments were made for gestational age and the other maternal characteristics. Copyright © 2012 ISUOG. Published by John Wiley & Sons, Ltd. Copyright © 2012 ISUOG. Published by John Wiley & Sons, Ltd.

PMID 22302307

Third-trimester pregnancy complications

Prim Care. 2012 Mar;39(1):95-113.

Newfield E. Source Department of Obstetrics and Gynecology, Contra Costa Regional Medical Center, 2500 Alhambra Avenue, Martinez, CA 94543, USA.


Complications arising in the third trimester often challenge the clinician to balance the concern for maternal well-being with the consequences of infant prematurity. The most serious and challenging antepartum issues relate to preterm labor and birth, hypertensive disorders, and bleeding events. This article guides the practitioner through decision-making and management of these problems. Copyright © 2012 Elsevier Inc. All rights reserved.

PMID 22309584

A morphometric study of suprarenal gland development in the fetal period

Surg Radiol Anat. 2012 Mar 20. [Epub ahead of print]

Ozgüner G, Sulak O, Koyuncu E. Source Department of Anatomy, Faculty of Medicine, Suleyman Demirel University, 32260, Isparta, Turkey,


PURPOSE: The present study's purpose was to examine the morphometric development of the suprarenal gland using anatomic dissection methods during the fetal period. METHODS: This study was performed on 172 human fetuses (76 males and 96 females) and 344 fetal suprarenal glands obtained from ages 9-40 weeks of gestation with no external pathology or anomaly. Fetuses were divided into 4 groups between gestational ages as follows: Group 1, 9-12 weeks (first trimester); Group 2, 13-25 weeks (second trimester); Group 3, 26-37 weeks (third trimester); and Group 4, 38-40 weeks (full term). Also, the fetuses were grouped into monthly cohorts: 9-12 weeks 3rd month, 13-16 weeks 4th month, 17-20 weeks 5th month, 21-24 weeks 6th month, 25-28 weeks 7th month, 29-32 weeks 8th month, 33-36 weeks 9th month, and 37-40 weeks 10th month. The suprarenal glands were dissected in the abdominal cavity. The dimensions (width, length, and thickness), volumes and weights of the suprarenal glands were evaluated. The ratio of the fetal suprarenal gland weight/fetal body weight, the ratio of the fetal suprarenal gland volume/fetal kidney volume, and the ratio of the fetal suprarenal gland dimensions/fetal kidney dimensions were evaluated. RESULTS: Mean values and standard deviations of all parameters according to gestational weeks and trimesters were calculated. It is found that all parameters increase with gestational age. There was significant correlation between gestational age and all parameters (p < 0.001). No significant differences were observed between sexes for any of the parameters (p > 0.05). There was no difference between the right and left sides of parameters except the thickness of the suprarenal glands. The left suprarenal glands were thicker than the right. The ratio of suprarenal volumes to kidney volumes was determined, and we observed that the ratio decreased during the fetal period. CONCLUSIONS: We believe that the results obtained from this study will be beneficial in understanding the development of suprarenal glands and also contribute to future studies in obstetrics, perinatology, and fetopathology.

PMID 22430763

Acute and Long-Term Purkinje Cell Loss Following a Single Ethanol Binge During the Early Third Trimester Equivalent in the Rat

Alcohol Clin Exp Res. 2012 Mar 8. doi: 10.1111/j.1530-0277.2012.01743.x. [Epub ahead of print]

Idrus NM, Napper RM. Source Department of Anatomy and Structural Biology, University of Otago, Dunedin, New Zealand. Abstract BACKGROUND: In the rat, binge-like ethanol (EtOH) exposure during the early neonatal period (a developmental period equivalent to the human third trimester) can result in a permanent deficit of cerebellar Purkinje cells (Pcells). However, the consequences of a moderate binge alcohol exposure on a single day during this postnatal period have not been established. This is an issue of importance as many pregnant women binge drink periodically at social drinking levels. This study aimed to identify both the acute and long-term effects of exposure to a single alcohol binge that achieved a mean peak blood EtOH concentration of approximately 250 mg/dl during early postnatal life using a rat model of fetal alcohol spectrum disorders. METHODS: Acute apoptotic Pcell death 10 hours after a moderate dose binge EtOH exposure from postnatal days (PDs) 0 to 10 was assessed using active caspase-3 immunolabeling. Acute Pcell apoptosis was quantified in cerebellar vermal lobules I-X using the physical disector method. Long-term effects were assessed at PD 60 using stereological methods to determine total Pcell numbers in the vermis, lobule III, and lobule IX, following a moderate dose binge EtOH exposure at PDs 0, 2, or 4. RESULTS: Acute apoptosis was induced by EtOH on PDs 1 to 8 in a time and lobular-dependent manner. For EtOH exposure on PD 2, significant long-term Pcell loss occurred in lobule III. EtOH exposure on PD 4 resulted in significant long-term Pcell loss throughout the entire vermis. CONCLUSIONS: These results indicate that a single, early EtOH episode of moderate dose can create significant and permanent Pcell loss in the developing cerebellum. Copyright © 2012 by the Research Society on Alcoholism.

PMID 22404759


Ultrasound screening in second and third trimester of pregnancy: an update

Acta Biomed. 2007 Dec;78(3):229-32.

Verrotti C, Caforio E, Gramellini D, Nardelli GB. Source Department of Obstetrics, Gynecology, and Neonatology, Section of Gynecology and Obstetrics, University of Parma.


Ultrasound screening of structural fetal malformations is mainly based on the use of ultrasounds during the second trimester of pregnancy. The diagnostic sensibility of ultrasounds varies in the different multicentric studies reported in literature and is correlated to different factors: gestation period, type of malformation, number of ultrasounds performed, operator experience, etc. Third trimester ultrasounds may identify late-onset malformations and offer adequate information for postnatal assistance.

PMID 18330085


Teenage pregnancy: use of drugs in the third trimester and prevalence of psychiatric disorders

Rev Bras Psiquiatr. 2006 Jun;28(2):122-5. Epub 2006 Jun 26.

Mitsuhiro SS, Chalem E, Barros MM, Guinsburg R, Laranjeira R. Source Research Unit of Alcohol and Drugs, Department of Psychiatry, Universidade Federal de São Paulo, São Paulo, SP, Brazil.


OBJECTIVE: To determine the prevalence of psychiatric disorders during pregnancy, the prevalence of cocaine and marijuana use during the third trimester of gestation and the socio-demographic characteristics of a population of low-income teenagers. METHOD: One thousand pregnant teenagers were evaluated using the Composite International Diagnostic Interview, and a socio-demographic and socio-economic questionnaire at the obstetric center of a public hospital in São Paulo, Brazil. Hair sample was collected for analysis. RESULTS: Of the 1000 pregnant teenagers interviewed, 53.6% were poor, 90.4% were unemployed, 92.5% were financially dependent and 60.2% dropped out of school. Those using drugs during the third trimester of pregnancy were equal to 6% (marijuana: 4%, cocaine: 1.7%, both: 0.3%). Those having at least one psychiatric disorder equaled 27.6%. The most frequent diagnoses were depression (12.9%), posttraumatic stress disorder (10.0%) and anxiety disorders (5.6%). DISCUSSION: Unstructured families, dropping out of school, unemployment and a low level of professional training are all contributing factors to the maintenance of an unfavorable socio-economic environment in which there is a high prevalence of cocaine and marijuana use during the third trimester of pregnancy and an abnormally high incidence of psychiatric disorders.

PMID 16810395


Third-trimester ultrasound dating algorithms derived from pregnancies conceived with artificial reproductive techniques

Ultrasound Obstet Gynecol. 2005 Aug;26(2):129-31.

Mongelli M, Chew S, Yuxin NG, Biswas A. Source Division of Women and Children's Health, Nepean Hospital, Penrith, NSW, Australia.


OBJECTIVE: To derive an accurate formula for ultrasound estimation of gestational age in late pregnancy. METHODS: A database of 123 singleton pregnancies conceived by artificial reproductive techniques with third-trimester ultrasound measurements was studied. Biometry variables included the fetal head circumference (HC) and femur length (FL). The dataset was equally divided into a derivation sample and a target sample. To derive the equations of best fit, regression analysis was used, with true menstrual age as the dependent variable and fetal biometry measurements as independent variables. The formulae were tested on the target set and the menstrual age estimates were compared with the actual menstrual age. Clinical performance was estimated in terms of systematic and random errors, absolute errors and their 95% CI values. RESULTS: The menstrual ages at time of scanning ranged from 26 to 41 weeks, with a mean of 33 weeks. The best performing derived formula was a combination of HC and FL. This had a random error of 7.5 days and prediction errors within a 95% confidence limit of -13 to +17 days. With FL only, the random error was 8.2 days, whereas using the HC only yielded a random error of 9.4 days. CONCLUSIONS: Ultrasound estimation of gestational age in late pregnancy is better than indicated by older publications. It is more accurately estimated by combining the HC with the FL than by using the FL measurements alone. Copyright 2005 ISUOG. Published by John Wiley & Sons, Ltd.

PMID 16041677


Phenotypic and functional analysis of human T lymphocytes in early second- and third-trimester fetuses

Clin Exp Immunol. 2002 Aug;129(2):302-8.

Zhao Y, Dai ZP, Lv P, Gao XM. Source Department of Obstetrics & Gynaecology, People's Hospital, Peking University, Beijing, China.


This study was undertaken to investigate the phenotypic and functional status of T lymphocytes of human fetuses from early second- to third-trimester. Cord blood samples were obtained from 19 healthy human fetuses (gestation weeks: 18-36), by cordocentesis, and 16 term newborns (gestation weeks 37-42). Maternal and unrelated male blood samples were also taken as controls. Percentage of lymphocytes in fetal white blood cells was 79.3%, reducing to 40% by term birth, much higher than that of adults. Cord blood mononuclear cells (CBMC), prepared by density gradient centrifugation followed by lysis of erythrocytes, were stained using PE- or FITC-labelled monoclonal Abs and analysed by flow cytometry. The frequencies of CD3+ T cells in fetal (40.1%) and neonatal (42.4%) CBMC were significantly lower than that of men (59.6%) and pregnant women (53.6%). Proportions of CD8+ T cells (9.5%), gammadelta-T cells (0.5%) and NK cells (4.8%) in fetal CBMC were also lower than that of neonates (except gammadelta-T cells) and adults. A negative linear correlation (r = -0.609) between the ratio of CD4+/CD8+ T cells in fetal blood and gestation age could also be established. Fetal CBMC showed vigorous spontaneous proliferation but failed to respond to mitogen (PHA) or allogeneic stimulation in vitro. The fetal mononuclear cells were unable to produce IL-2, IL-4 or IFN-gamma, but spontaneously secreted IL-10, IL-6 and TNF-alphain vitro. Stimulation with PHA up-regulated the production of IL-10, IL-6 and TNF-alpha substantially.

PMID 12165087