IVF, Pregnancy loss and diagnossi Flashcards
give some factors sucessfull IVF requires?
- Adequate gametes (numerically and functionally)
- Clear passageways
- A supportive uterine lining
- A normal maternal endocrinological response to a fertilised ovum
Adequate implantation and successful placentation
What’s the difference between primary and secondary infertility?
‣PRIMARY - inability to become pregnant and no previous pregnancies
‣SECONDARY - inability to become pregnant despite previous pregnancy (inc. ectopic or miscarriage)
whats Aspermia
- Aspermia: no semen in ejaculate
- Retrograde ejaculation, prostatic dysfunction
whats Azoospermia
• Azoospermia: no sperm in ejaculate • Non-obstructive or obstructive
whtas Oligospermia
Oligospermia: low number of sperm
whats Asthenospermia
sperm with poor motility
whast Teratospermia:
Teratospermia: Abnormal sperm morphology
whats Necrozoospermia
Necrozoospermia: dead or immotile sperm
whats
Oligoasthenoteratospermia (OATS)
Oligoasthenoteratospermia (OATS)
• Most common finding,usually ‘idiopathic’
is there a huge pathwy for infertile people to go down?
yes
describe Intrauterine insemination
‣Minimum ovarian stimulation (< 3 follicles)
‣hCG-induced ovulation when follicle >21mm
‣Sperm insertion 2 days later with use of speculum
‣Generally attempt 3 cycles prior to IVF if <34yrs
‣Indications:
- Same-sex relationships
- Physical disability or psychosexual problem
- Specific consideration in relation to methods of conception (for example, after sperm washing where the man is HIV positive)
give some pactors which can affect fertility
how do we prepare for IVF?
‣Preparation:
‣Pituitary-ovarian down-regulation with GnRH agonist (intranasal or s/c)
‣Ovarian stimulation using recombinant gonadotrophins (s/c)
‣Follicular phase monitoring with USS/endocrinology
how do we induce ovulation in IVF
‣Inducted ovulation
‣Recombinant hCG (s/c) mimics LH surge
‣Aim to collect 8-10 oocytes
‣Pessaries (crinone, cyclogest, utrogestan) for luteal support
‣Progesterone needed to ensure endometrial receptivity for implantation
which 5 factors predict sucess of IVF?
- Younger female age
- Number of previous treatment cycles
- Previous pregnancy history
- Body mass index
- Lifestyle factors
descrbie intracytoplasmic sperm injection in IVF
‣Oocyte treated with hyaluronidase to remove cumulus cells
‣Metaphase II
‣Day 1: 2 polar bodies and 2 clear pronuclei with aligned nucleoli
‣Shortly after should see first cleavage division
‣Day 2: surplus frozen
‣Day 5: artificial implantation
‣~50% of cleaved embryos do not reach blastocyst stage
how do we select the best spermatozoa
are IVF embryos screened for genetic issues?
‣Used in all cases of artificial insemination
‣Embryo biopsy and chromosomal analysis (FISH, CGH array, etc.)
‣Mitochondrial replacement therapy
‣Can be used for standard IVF as well as ICSI
‣Requires special HFEA licensing
‣May indicate important chromosomal abnormality before implantation stage
risks of IVF?
- Ovarian hyperstimulation syndrome (OHSS) Following use of gonadotrophins to stimulate ovulation
- Ovarian enlargement due to multiple ovarian cysts and acute fluid shift to extracellular space
- Mild symptoms include abdominal bloating and feeling of fullness, nausea, diarrhea, and slight weight gain
- More severe symptoms include SoB, pleural effusion, oliguria, chest pains, marked abdominal distention
- Difficult to predict but can be life-threatening
- Avoided by elective freeze-all-embryos to reduce the need for repeated treatment cycles
- Multiple pregnancy
- HFEA recommends elective single embryo transfer wherever possible
- Multiple pregnancy is significantly more dangerous than single pregnancy
- Post-op bleeding/infection
- Menopause Sx
are lots of pregnancies lost in the first week?
yes
Is R&Ls work regarding pregnancy loss rates anyg goof?
noo - its far to large a range to be practically useful.
what re the causes of early pregnancy loss?
‣Embryonic abnormality
‣Aneuploidy
‣Uterine abnormality
‣Developmental abnormalities
‣Other disorders, prolapse, infection etc…
‣Cervical abnormality
‣Systemic abnormality
‣Antiphospholipid syndrome (AI hypercoagulable state - classically causing thrombosis or pregnancy complications)
‣Hormonal insufficiency
‣Drugs/teratogens
‣Immune rejection
‣NOT due to stress, intercourse, emotional trauma, exercise
describe aneuploidy with regard to early pregnancy loss?
‣Abnormal number of chromosomes
‣Found in 5-10% of clinical pregnancies
‣Embryos may have mechanisms in place to eliminate these abnormal cells, thus aneuploidy may not always lead to pregnancy loss
‣Aneuploidy in trophoblasts may actually support normal placentation
which genes control early lineage specification?
At the blastocyst stage three distinct cell types are present:
what are they?
At the blastocyst stage three distinct cell types are present: trophectoderm, primitive endoderm, primitive epiblast
describe hippo in the early embro
in outer contact free cells - Hippo is off.
- anterior polarity complex sequesters AMOT, prevents activation of Hippo kinases (LATS)
- so YAP1 accumulates in the nucleus - and activates genes responsible for trophoectoderm fate - eg GATA3
describe where HIPPO is on?
interior cells.- hippo on
LATS activated = phosphorylation of YAP - prevents translocation into nucleus. GATA3 not expressed.
is FGF signalling required for EPI developement in human embryos?
no
give some examples of how we can study gene function in embryos
- Single cell RNA sequencing
- Immunofluorescence analysis
- CRISPR/Cas9 mutagenesis - knock out genes
At birth: ___% of neonates have a significant congenital abnormality
At birth: 2-3% of neonates have a significant congenital abnormality
give some examples of
‣Fetal structural abnormalities
‣Fetal structural abnormalities
‣neural tube defects
‣congenital heart disease
‣brain malformations
‣renal abnormalities
describe neural tube defects?
- Anencephaly (10%) - absence of major portions of brain, skull or scalp
- Spina bifida (40%) - defective closure of spinal column
- Majority are open defects due to failed neural tube closure, leaving neural tissue/meninges exposed
- Closed defects compromise 15-20%
- Diagnosed with maternal serum aFP (open defects only)
- Folic acid supplementation has helped decline in last 20-30yrs
15-20% of NTDs are closed (skin covers defect) and not detectable by biochemical testing of what protein?
15-20% closed (skin covers defect) and not detectable by biochemical testing (alpha-fetoprotein levels)
give some chromosomal abnormalities?
‣Chromosomal abnormalities
‣Turner’s syndrome (XO)
‣Down’s syndrome (TS21)
‣Edward’s syndrome (TS18)
‣Patau syndrome (TS13)
describe downs syndrome
Intellectual disability – mild to moderate learning difficulties
Dysmorphic – flat nasal bridge, up slanting palpebral fissures, epicanthic folds, protruding tongue, single palmer crease, clinodactyly, sandal gap
Cardiac defects – 40% of cases
describe edwards ayndrome
- trisomy 18
- Learning disability
- severe Dysmorphic – micrognathia, prominent
occiput
- Clenched overlapping fingers
- Prominent heels & rocker-bottom feet
- Cardiac defects
describe patau syndrome
- Mental disability – severe
- Dysmorphic – cleft lip, cleft palate, holoprocencephaly, postaxial polydactyly
- Renal abnormalities
- Cardiac defects
correlation between Maternal age and chromosome abnormalities found at amniocentesis
All pregnant women at least 2 ultrasound scans (USS) during their pregnancy:
when?
- at 8 to 14 weeks (dating scan + nuchal translucency for Down syndrome)
- at 18 to 21 weeks (detailed “anomaly scan”)
describe the The Early Pregnancy Scan
- < 15 weeks
- gestational age accurately – essential for screening of trisomy 21
- fetal crown rump length (CRL) <12 weeks - Bi-parietal diameter >12 weeks
- viability
- foetal number, and in multiple pregnancies the chorionicity/amnionicity
- detection of gross foetal abnormalities
what is this?
Nuchal translucency (NT) thickness measurements
- Describes collection of fluid behind fetal neck
- Performed between 11 and 13 weeks gestation
- If increased – MAY be associated with pathology
Increased nuchal translucency thickness seen in multiple conditions:
give a few
- Trisomy 21 - biggie
- Cardiac failure in association with congenital heart disease
- venous congestion in head and neck caused by constriction of
- foetal body as in:
- amniotic band sequence
- superior mediastinal compression caused by diaphragmatic hernia
- Narrow chest found in skeletal dysplasia
- Abnormal or delayed development of lymphatic system
- Impaired fetal movement due to neuromuscular disorder
- Foetal anaemia or hypoproteinaemia
- Congenital infection through anaemia or cardiac dysfunction
- Some rare single gene disorders
The 20 week foetal anomaly scan purpos?
- reassure the woman that her baby appears to have no obvious structural abnormalities, and if this is not the case, to identify anomalies:
1. not compatible with life
2. associated with high morbidity /long term disability
3. foetal conditions with the potential for intrauterine therapy
4. foetal conditions that will require postnatal investigations or treatments
Anencephaly detectable ___ weeks
Anencephaly detectable 10-14 weeks
Spina bifida difficult to visualize directly until ______ weeks
Spina bifida difficult to visualize directly until 16-22 weeks
Indirect cranial or cerebellar markers are…..
Indirect cranial or cerebellar markers are
- Lemon sign
- Banana sign
what is Meckel-Gruber syndrome
autosomal recesive
Meckel-Gruber syndrome is a rare, lethal ciliopathic genetic disorder, characterized by renal cystic dysplasia, central nervous system malformations (occipital encephalocele), polydactyly (postaxial), hepatic developmental defects, and pulmonary hypoplasia due to oligohydramnios
2 things in maternal circulation we can test for?
alpha fetal protein
fetal DNA
describe
Maternal serum screening example: alphafetoprotein (AFP)
AFP reaches maternal serum:
- directly across placenta
- indirectly from amniotic fluid across chorion and amnion and
uptake by maternal vasculature in uterine decidua
Measured by highly specific immunoassay methods
Levels change with gestation (lower in 2nd vs 1st trimester)
Used to screen for NTDs from 1970s and trisomy 21 from 1990s
T or F for alpha fetal protein
Accurate estimate of gestation at which sample is obtained is essential for interpretation of the serum marker levels
T
fetal protein alpha picture
does maternal age have a high or low predicitve value in downs syndrome?
low predictive value
Prenatal screening for Down syndrome using serum markers
describe
Information from pregnancy in both 1st and 2nd trimester used to modify maternal age risk
- Serum screening of multiple independent markers increases sensitivity and specificity of the screening test
- 1st trimester nuchal scan data is now being used routinely in some centres
- Note: screening for Down syndrome in the UK varies from region to region
give some invasinve and non invasive methods of prenatal diagnosis in high risk pregnancies?
• Invasive
Chorionic Villus Sampling
Amniocentesis
Foetal blood sampling • Non-invasive
Ultrasound Free foetal DNA
describe Chorionic Villus Sampling (CVS)
- Enables samples to be taken in first trimester after 11 weeks
- Chorionic villi are fetal in origin; derived from outer layer of the blastocyst i.e. trophoblast
- Maternal material must be discarded
- Gives good preparations of DNA without culture
- Chromosome analysis can be done rapidly within 24 hours
- Best quality chromosome analysis after culture (2 weeks) ~1% risk miscarriage
- Possibility of surgical termination in first trimester
describe Amniocentesis
- 10 – 20 mls of amniotic fluid sampled transabdominally under USS
- Usually 16 weeks gestation (or later e.g. 20 weeks after abnormal scan)
- Cells from amnion, fetal skin, urinary tract pelleted
- Cultured for 2 weeks to get sufficient numbers to analyze
- Longer culture may be needed for DNA or biochemical studies
- nb rapid trisomy screen results by PCR bypass this time requirement 0.5% risk of miscarriage
- Medical (late) termination of pregnancy
describe cell free fetal DNA serum screening
- ‣From 7w
- ‣Trophoblast in origin
- ‣Representative of entire fetal genome
- ‣Distinguishable from maternal DNA by being shorter
- ‣Fetal sexing (PCR detection of Y-chromosome at 99.5% accuracy)
- Detection of aneuploidies/inherited disorders (not yet in NHS practice
whatg is fetoscopy
‣Endoscopic analysis through an incision
‣Fetal skin biopsy for detection of hereditary skin disorders fetal blood sampling
‣Also associated with a risk of miscarriage
fat
mamba
