BGDA Practical Placenta - Diagnostic Techniques - Revision history

Z8600021 at 11:29, 2 Haziran 2019

2019-06-02T11:29:35Z

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	* 40 weeks ({{GA}}) - about 600 mL at term.		* 40 weeks ({{GA}}) - about 600 mL at term.

			<br>
			{{BGDA Practical 14 - Diagnostic Interactive}}

			<br>

	==Additional Information==		==Additional Information==

Z8600021 at 07:49, 1 Haziran 2019

2019-06-01T07:49:14Z

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	'''Noninvasive prenatal screening for fetal trisomies 21, 18, 13 and the common sex chromosome aneuploidies from maternal blood using massively parallel genomic sequencing of DNA'''{{#pmid:24657131\|PMID24657131}}		'''Noninvasive prenatal screening for fetal trisomies 21, 18, 13 and the common sex chromosome aneuploidies from maternal blood using massively parallel genomic sequencing of DNA'''{{#pmid:24657131\|PMID24657131}}
	:"The objective of this study was to validate the clinical performance of massively parallel genomic sequencing of cell-free deoxyribonucleic acid contained in specimens from pregnant women at high risk for fetal aneuploidy to test fetuses for {{trisomy 21}}, {{trisomy 18}}, and {{trisomy 13}}; fetal sex; and the common sex chromosome aneuploidies (45, X; 47, XXX; 47, XXY; 47, XYY). ...Our prospective study demonstrates that noninvasive prenatal analysis of cell-free deoxyribonucleic acid from maternal plasma is an accurate advanced screening test with extremely high sensitivity and specificity for trisomy 21 (>99%) but with less sensitivity for trisomies 18 and 13. Despite high sensitivity, there was modest positive predictive value for the small number of common sex chromosome aneuploidies because of their very low prevalence rate."		:"The objective of this study was to validate the clinical performance of massively parallel genomic sequencing of cell-free deoxyribonucleic acid contained in specimens from pregnant women at high risk for fetal aneuploidy to test fetuses for {{trisomy 21}}, {{trisomy 18}}, and {{trisomy 13}}; fetal sex; and the common sex chromosome aneuploidies (45, X; 47, XXX; 47, XXY; 47, XYY). ...Our prospective study demonstrates that noninvasive prenatal analysis of cell-free deoxyribonucleic acid from maternal plasma is an accurate advanced screening test with extremely high sensitivity and specificity for trisomy 21 (>99%) but with less sensitivity for trisomies 18 and 13. Despite high sensitivity, there was modest positive predictive value for the small number of common sex chromosome aneuploidies because of their very low prevalence rate."

			Note that some recent statistical analysis of the risk of miscarriage following {{amniocentesis}} or {{chorionic villus sampling}}{{#pmid:31124209\|PMID31124209}} suggests that "The procedure-related risks of miscarriage following amniocentesis and CVS are lower than currently quoted to women. The risk appears to be negligible when these interventions are compared to control groups of the same risk profile."

	==References==		==References==

Z8600021 at 07:29, 1 Haziran 2019

2019-06-01T07:29:47Z

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	{{Term Placenta Measurements table}}		{{Term Placenta Measurements table}}

			===Replacing Invasive Techniques===

			'''Noninvasive prenatal screening for fetal trisomies 21, 18, 13 and the common sex chromosome aneuploidies from maternal blood using massively parallel genomic sequencing of DNA'''{{#pmid:24657131\|PMID24657131}}
			:"The objective of this study was to validate the clinical performance of massively parallel genomic sequencing of cell-free deoxyribonucleic acid contained in specimens from pregnant women at high risk for fetal aneuploidy to test fetuses for {{trisomy 21}}, {{trisomy 18}}, and {{trisomy 13}}; fetal sex; and the common sex chromosome aneuploidies (45, X; 47, XXX; 47, XXY; 47, XYY). ...Our prospective study demonstrates that noninvasive prenatal analysis of cell-free deoxyribonucleic acid from maternal plasma is an accurate advanced screening test with extremely high sensitivity and specificity for trisomy 21 (>99%) but with less sensitivity for trisomies 18 and 13. Despite high sensitivity, there was modest positive predictive value for the small number of common sex chromosome aneuploidies because of their very low prevalence rate."

	==References==		==References==

Z8600021 at 07:22, 1 Haziran 2019

2019-06-01T07:22:22Z

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	{{Med Prac additional Information}}		{{Med Prac additional Information}}


			{{Prenatal diagnosis}}

			<br>
	Term placental composition, villous capillarization and the mean cross-sectional areas of peripheral villi and capillaries, data from a study sample of 15 normal placenta (mean placental volume, 652 ml).{{#pmid:19141109\|PMID19141109}}		Term placental composition, villous capillarization and the mean cross-sectional areas of peripheral villi and capillaries, data from a study sample of 15 normal placenta (mean placental volume, 652 ml).{{#pmid:19141109\|PMID19141109}}

Z8600021 at 04:07, 2 Haziran 2018

2018-06-02T04:07:26Z

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 Term placental composition, villous capillarization and the mean cross-sectional areas of peripheral villi and capillaries, data from a study sample of 15 normal placenta (mean placental volume, 652 ml).{{#pmid:19141109|PMID19141109}}
+{{Term Placenta Measurements table}}
 ==References==

Z8600021 at 03:59, 2 Haziran 2018

2018-06-02T03:59:35Z

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	{{Med Prac additional Information}}		{{Med Prac additional Information}}

	Term placental composition, villous capillarization and the mean cross-sectional areas of peripheral villi and capillaries, data from a study sample of 15 normal placenta (mean placental volume, 652 ml). ~~<ref><pubmed>~~19141109~~</pubmed></ref>~~		Term placental composition, villous capillarization and the mean cross-sectional areas of peripheral villi and capillaries, data from a study sample of 15 normal placenta (mean placental volume, 652 ml).{{#pmid:19141109\|PMID19141109}}


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	\|}		\|}


			==References==

	<references/>		<references/>

Z8600021 at 03:28, 5 Haziran 2017

2017-06-05T03:28:08Z

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	* '''placental thickness''' - is measured at its mid-portion from the chorionic plate to the basilar plate, on a longitudinal plane (less than 4 cm at term). Excludes any abnormalities (fibroids, myometrial contractions, or venous lakes). The placental thickness approximates in millimeters to the weeks of gestation.		* '''placental thickness''' - is measured at its mid-portion from the chorionic plate to the basilar plate, on a longitudinal plane (less than 4 cm at term). Excludes any abnormalities (fibroids, myometrial contractions, or venous lakes). The placental thickness approximates in millimeters to the weeks of gestation.
	* '''placental volume''' - is measured by a range of different methods and calculations, more recently with three-dimensional ultrasound.		* '''placental volume''' - is measured by a range of different methods and calculations, more recently with three-dimensional ultrasound.

			==Amniotic Fluid Volume==
			The amniotic fluid volume increases as the embryo and then fetus grows and rate of change varies during the pregnancy.
			* up to 8 weeks - increases at 10 ml/week
			* 8 to 13 weeks - increases at 25 ml/week
			* 13 to 21 weeks - increases at 60 ml/week
			* 21 to 33 weeks - amniotic volume increase starts decreasing and eventually levels.
			* 34 weeks ({{GA}}) - peaks at about 800 mL.
			* 40 weeks ({{GA}}) - about 600 mL at term.

Z8600021 at 01:56, 5 Haziran 2017

2017-06-05T01:56:18Z

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	{\|		{\|
	\| [[File:Cvs.jpg]]		\| [[File:Cvs.jpg]]
	\| Chorionic Villus Sampling test is done in ~~the 10th~~ to ~~12th week after the first day of the mother's last menstrual period~~. The test is done by looking at cells taken from the chorionic membrane or placenta. No anaesthetic is required, and a test result is usually available in two to three weeks.		\| Chorionic Villus Sampling test is done in {{GA}} week 10 to 12.

			The test is done by looking at cells taken from the chorionic membrane or placenta. No anaesthetic is required, and a test result is usually available in two to three weeks.

	When the test is carried out by an obstetrician experienced in the technique, the risk of miscarriage related to the test is about 2%.		When the test is carried out by an obstetrician experienced in the technique, the risk of miscarriage related to the test is about 2%.
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	{\|		{\|
	\| [[File:Amniocentesis.jpg]]		\| [[File:Amniocentesis.jpg]]
	\| Amniocentesis is a prenatal diagnostic test carried out mainly between ~~14th~~ to ~~18th week of pregnancy~~. Amniotic fluid is taken from the uterus, sent to a diagnostic laboratory and embryonic cells isolated from the amniotic fluid. No anaesthetic is required, and a result is usually obtained in about three to four weeks. When the test is carried out by an obstetrician experienced in the technique, the risk of a miscarriage related to the test is about 1 %.		\| Amniocentesis is a prenatal diagnostic test carried out mainly between {{GA}} week 14 to 18.

			Amniotic fluid is taken from the uterus, sent to a diagnostic laboratory and embryonic cells isolated from the amniotic fluid. No anaesthetic is required, and a result is usually obtained in about three to four weeks. When the test is carried out by an obstetrician experienced in the technique, the risk of a miscarriage related to the test is about 1 %.

Z8600021 at 04:22, 10 Haziran 2014

2014-06-10T04:22:54Z

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	:'''Links:''' [[Chorionic villus sampling]]		:'''Links:''' [[Chorionic villus sampling]] \| [[Trisomy 21]] \| [[Abnormal_Development_-_Genetic\|Abnormal Genetic]]
	\|}		\|}

Z8600021 at 01:57, 10 Haziran 2014

2014-06-10T01:57:49Z

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	[[File:Gray0038.jpg\|thumb\|~~300px~~\|Fetus in Utero Between fifth and sixth months]]		[[File:Gray0038.jpg\|thumb\|200px\|Fetus in Utero Between fifth and sixth months]]