Lecture 12

Question 1

embryo

Answer 1

conception to end at 9th week post LMP

Question 2

fetal

Answer 2

10 weeks +

Question 3

LMP

Answer 3

1st day of LMP

scan offered at 8-10 weeks

Question 4

first signs of pregnancy

Answer 4

missed period

common symptoms - sickness/ bloating

due to hormone changes (hCG, estrogen and progesterone)

Question 5

implantation

Answer 5

cervix closes womb but increasing mucus so endometrium can continue to develop

Question 6

pregnancy diagnosis

Answer 6

urine tests

blood tests - hCG doubles in 48 hours

Question 7

hCG decrease

Answer 7

when placenta takes over

Question 8

ultrasound

Answer 8

freq 2-20mHZ
2D/3D/4D

pulse reflected at tissue interfaces - strength of reflection depends on tissue density

fat attenuates return signal

Question 9

advantages of ultrasound

Answer 9

safe
very experienced
safe

Question 10

ultrasound uses

Answer 10

diagnosis
screening
surveillance

Question 11

ultrasound risks

Answer 11

heat

cavitation

Question 12

1st trimester USS

Answer 12

transabdominal (TA)
transvaginal (TV)

thickened endometrium is a good indication but not a diagnostic

Question 13

thickened endometrium can be seen in

Answer 13

1st trimester
late luteal phase
decidual reaction in an ectopic pregnancy
retained products of conception (miscarriage)

Question 14

early USS

Answer 14

gestation sac 
day 12-13 of development 
chorionic cavity 
decidual reaction 
TV - time of missed period 
TA - 5 weeks post period

Question 15

yolk sac

Answer 15

mesoderm that gives rise to blood vessels and blood cells

provides nutrients

Question 16

yolk sac visible from

Answer 16

37 days post LMP

initially very close to foetus

Question 17

yolk sac after 45 days

Answer 17

growth
enlargement of amniotic cavity
not visible after 11 weeks

Question 18

when is pregnancy viable

Answer 18

heart pulsations can be visualised within gestation sac

TV - 5.5 weeks post LMP
TA - 6 weeks post LMP

Question 19

embryogenesis

Answer 19

differentiation
migration
folding

Question 20

when does embryogenesis occur

Answer 20

trilaminar embryo week 3

Question 21

brain and spinal cord origin

Answer 21

neural plate develops from ectoderm day 18-19

neural tube closes day 27

Question 22

heart formation

Answer 22

mesenchyme cord canalsies week 4

dilates and constriction to form 4 chambers in weeks 4-7

Question 23

all major organs form by

Answer 23

week 6-10

Question 24

teratogenesis

Answer 24

developmental defects by a chemical agent

dose dependent, exposure

smoking/ drugs/ alcohol/ thalaminde

Question 25

first trimester complications

Answer 25

experience bleeding - normal, ectopic or miscarriage

Question 26

miscarriage

Answer 26

90% of chromosomal abnormalities that implant 60% of all 1st trimester miscarriages are chromosomal abnormalities 93% normal chromosomes carry on

Question 27

normal embryos that miscarry

Answer 27

maternal abnormalities: - poor decidualisation - spiral arteries restrict remodelling - failure of immune recognition - blood clotting system fails

Question 28

implantation stats

Answer 28

70% implant 60% recognised as pregnancies 50% go on to live birth

Question 29

ectopic pregnancies

Answer 29

embryos that implant outside the uterus (broad ligaments)

Question 30

ectopic risks

Answer 30

haemorrhage - rupture and internal 10 reported deaths

Question 31

ectopic diagnostics

Answer 31

hCG progesterone USS aneuploidy screen

Question 32

abnormal karyotype

Answer 32

monosomy and trisomy causes by errors meiosis and fail before or after implantation

Question 33

trisomy 21

Answer 33

downs | 1:600

Question 34

trisomy 13

Answer 34

pataus | 1:5000

Question 35

trisomy 18

Answer 35

edwards | 1:3000

Question 36

to reduce risk of trisomy

Answer 36

use younger persons oocytes | ART/ IVF

Question 37

chromosomal abnormalities stats

Answer 37

oocytes - 20% sperm - 7% human zygotes - 40% blastocysts - 50%

Question 38

nuchal translucency

Answer 38

back of foetal neck has translucent material size increase after 11 weeks by 0.37cm blood tests and screens

Question 39

problems with screening

Answer 39

high risk 1:150 invasive can cause miscarriage QT-PCR for trisomy

Question 40

diagnostic testing for abnormalities

Answer 40

aminocentesis CVS withdraw fluid from baby at 15 weeks

Question 41

QT PCR

Answer 41

short tandem repeats to detect copy number targets whole chromosome markers rapid results - 2 days

Question 42

out dated tests

Answer 42

FISH | full karyotype

Question 43

non-invasive prenatal test (NIPT)

Answer 43

cell free foetal DNA (cffDNA) derived from foetus via mother's plasma 4-5 weeks detection and quantified at 10 weeks

Question 44

cfDNA and karyotype

Answer 44

used for haemophilia, Rhesus disease and aneuploidy

Question 45

MELISSA STUDY

Answer 45

no false positives highly sensitive to trisomy private UK and US

Question 46

second trimester screening

Answer 46

foetus is fully formed | no further organogenesis

Question 47

anomaly scan

Answer 47

18-20 weeks aneuploidy pre term labour placental problems

Question 48

exomphalos

Answer 48

gut stays outside

Question 49

during 18 weeks gut

Answer 49

gut exteriorises and then rotates and goes back in

Question 50

gastroschisis anomaly

Answer 50

abdominal wall defect invasive test aminocetetsis QT PCR

Question 51

CGH - microarray comparative genetic hybridisation

Answer 51

oligonucleotides probes representing whole genome on a glass slide (25-75bp) Fluorscently labelled DNA from patient compared to reference pool DNA labelled with flurochrome

Question 52

PGT - pre-implantation genetic testing

Answer 52

used with families with known genetic abnormalities performed in ART of IVF take 2 blastomeres which the embryo will be able to reproduce - undergo CGH

Question 53

future tech

Answer 53

high resolution chromosomal analysis of cffDNA next gen sequencing to detect single nucleotide polymorphisms

Question 54

NGS problems

Answer 54

expensive | time consuming