Birth Flashcards
What percentage of all pregnancies ends in miscarriage?
50%
What is the most common cause of miscarriage?
Chromosomal abnormality
How many babies at term have a chromosomal abnormality?
1/250
What are the three types of chromosomal abnormalities?
- Aneuploidy
- Rearrangement
- Deletions or duplications
What is aneuploidy?
Too many or too few chromosomes
What are three types of chromosomal rearrangements?
- translocation
- inversioin
- complex chromosome rearrangement
What are two common causes of aneuploidies?
- Malsegregation
2. Raised maternal age
When does Malsegregation of chromosomes happen?
- In gonad during meiosis —> abnormal gamete
- During mitosis in the germline —> mosaicism in the gonad
- During mitosis in the early embryo —> mosaicism in the embryo
What are the two types of chromosomal translocations?
- Robertsonian
2. Reciprocal
What happens in Robertsonian translocation?
Two chromosomes halves fuse two form one
What is the most common Robertsonian translocation?
Chromosome 13 and 14
What is the prognosis for Robertsonian translocation?
Phenotypically normal, may have increased reproductive risk
What is reciprocal translocation?
Two chromosomes exchange halves (total number of chromosomes normal)
What is the prognosis of reciprocal translocation?
Phenotypically normal
What is the prevalence of T21?
1/800
0.12%
What is Edwards syndrome?T
T18
What is Patau syndrome?
T13
What is Turner’s syndrome?
45, X
What is Klinefelter syndrome?
47, XXY
What are three types of monogenetic disorders?
- Spinal muscular atrophy
- Cystic Fibrosis
- Duchenne muscular dystrophy
What is genetic testing?
sample from the pregnancy for the presence of specific disorders (invasive)
What is genetic prenatal screening?
produces a risk figure for the fetus of having certain abnormalities, this is NOT a diagnosis
What does QF-PCR detect?
Aneuplodies
What do array comparative genomic hybridisation tests detect?
Genomic imbalance across genome
T13, T18, T21
What is FISH used for?
to detect unbalanced products of a known familial unbalanced rearrangement
What invasive testing tools can be employed?
- Chronic villus sampling
- Amniotic fluid sampling
- Fetal blood sampling
What non-invasive testing tools can be employed?
Peripheral maternal blood sampling
What is a normal order of prenatal testing (tools)?
Samples from amniotic fluid, chronic villus fluid or fetal blood
QF-PCR for trisomy
FISH for unbalanced products of the rearrangement
What prenatal tests are routine?
Infectious disease
Screening for T21, T18, T13
What is a combined prenatal test to detect trisomies?
- Maternal age
- Measurement of nuchal translucency
- Gestational age from the length of the fetus
- Level of two hormones (PAPP-A and B-hCG) in maternal blood
When can a combined prenatal test be carried out?
10-14 weeks
When can a quadruple test be carried out?
14-22 weeks
What does a quadruple test measure?
AFP, hCG, unconjugated estriol, inhibin A
What can the 20 week anomaly scan detect?
Patau, Edwards, Downs
What percentage of Down fetuses will not be detected?
10-20%
What three genetic tests are available?
- testing for a singular gene disorder
- Parental chromosome arrangement
- Genome testing following the detection of fetal abnormality
What are indications for diagnostic testing?
- High risk screening result
- Fetal abnormality detected at 12 or 20-week scan
- Family history
- High maternal anxiety
What is the miscarriage risk for chorionic villus sampling?
0.2%
What is the miscarriage risk for amniocentesis?
0.1%
What is the future for prenatal testing?
Non-invasive genetic testing based on free fetal DNA in maternal bloodstream
What is NIPT?
Highly sensitive screening test for detecting T21, T18, T13
How does NIPT work?
Non-invasive genetic testing based on free fetal DNA in maternal bloodstream
What two events need to happen during parturition?
- Requires softening and effacement of the cervix
2. Development of uterine contractions
How many stages does labour have?
3
What are the stages of labour?
- Stage 1
- Latent phase - contractions develop and cervic softens
- Active phase - cervix is dilated, regular contractions
- Stage 2 - cervix fully dilated and strong contraction in fundus
- Short phase
- Delivers baby
- Stage 3 - placenta is delivered and the umbilical cord is clamped
Between how many weeks are most babies born?
37-40
What factors may induce birth?
- Growing baby (As fetus grows, it will mature HPA and will start releasing CRH, ACTH and cortisol )
- Cortisol feeds to the placenta which stimulates placental CRH and membrane prostaglandines- Stimulates inflammation
- Placenta CRH feeds back on fetus CRH —> feedforward symptoms amplifying all the signals
- Stimulates inflammation
- Placental hormones
- Maternal signals
What does the mucus plug do?
Mechanical and chemical barrier against infections
What molecules trigger cervix softening?
NOS, COX2
Prostaglandin production (cortisol)
Matrix metalloproteinases
What two molecules help with contractions?
Oxytocin and prostaglandins
How does suckling help with milk production?
Ensures prolactin secretion
How does suckling help with milk secretion?
Stimulates oxytocin, which helps contract cells surrounding alveoli full of milk
What is a normal birth?
Spontaneous in onset, low-risk at the start of labour and remaining so throughout labour and delivery. The infant is born spontaneously in the vertex position between 37 and 42 completed weeks of pregnancy. After birth mother and infant are in good condition
Why is a normal birth important?
- Physical recovery
- Psychological benefits
- Colonisation of the baby
- Higher rates of breastfeeding success
- Natural bonding process
What is stage 1 of labour?
Onset of symptoms to full cervical dilatation
What is stage 2 of labour?
Full cervical dilatation to birth of the baby
What is stage 3 of labour?
Birth of the baby to delivery of the placenta and control of blood loss
What two stages does stage 2 of labour have?
- Passive stage
- No urge to push
- Lasts for about an hour
- Active stage
- Uncontrollable urge to push
- Baby comes down through birth canal
- Head delivers in anterior-posterior position: looking down. Head and shoulders rotate while the baby moves down
How, anatomically, is the baby maneuvered through the birth canal?
- Presentation of the head
- Rotation and delivery of anterior shoulder
- Delivery of posterior shoulder
- Delivery of lower body and umbilical cord
What maternal observations should be monitored during birth?
Contractions Dilatation Vital signs Drugs and fluids Vaginal loss Emotional state
What fetal observations should be monitored during birth?
Fetal heart activity
Fetal position
Descent of the head
What factors can make birth easier?
- Pain relief
- Continuous support
- Continuity of care
- Environment
What pharmacological pain relief can be given during birth?
Entonox (nitrous gas and oxygen)
Opioids
Epidural
What is puerperium?
the time from the end of the third stage through the first few weeks after delivery, as the woman’s body returns to a non-pregnant state (usually 6-8 weeks)
What areas physiologically change after birth?
- Uterus
- Periuneum
- Breasts
- Abdomen
- Haemotological
What uteral changes occur after birth?
- Involution
2. Lochia (vaginal discharge) - goes away after 6-8 weeks
What blood-related changes happen after birth?
increase in lood volume
More vulnerable to infection
What serious mental health problems can occur after birth?
- Postnatal depression
- PTSD
- Puerperal psychosis
How can postnatal depression be treated?
- Self-help strategies - relaxation, mindfulness, exercise
- Talking therapies (CBT)
- Medication
Which three viruses can cause human embryonic malformations?
Parvovirus
Rubella
CMV
How does Non-invasive prenatal testing (NIPT) work?
Sequencing of maternal plasma. In T21/18/13 there will be a higher proportion of chromosome fragments compared to reference samples.
Cell-free DNA testing
Circulating fetal DNA is sequenced to look for chromosomal abnormalities.
What are non-hormonal treatments for menopause?
Reduction in hot flushes and night sweats - clonidine (alpha-2 agonist)
Improving low mood - selective serotonin reuptake inhibitors
Treatment of joint and muscle pains - gabapentin
Treatment of atrophy/dryness - lubricants like Replens
What are the risks for the mother if the mother is obese during pregnancy?
Gestational diabetes
Caesarean
Pre-eclampsia
What are the risks for the child if the mother is obese during pregnancy?
Still birth
NICU admission
Macrosomia / LGA
What happens during the anaphase of mitosis?
Anaphase is where the paired chromosomes separate and move to opposing sides of the cell
What happens during the metaphase of mitosis?
Metaphase is where the chromosomes are aligned in the middle of the cell
What happens during the prometaphase of mitosis?
Prometaphase is when the nuclear membrane breaks down, allowing microtubules to attach to chromosomes
What happens during the prophase of mitosis?
Prophase is when chromatin in the nucleus condenses
What happens during the telophase of mitosis?
Telophase is where the chromatids arrive at opposite poles of the cell
What is shoulder dystocia?
Shoulder dystocia is when, after vaginal delivery of the head, the baby’s anterior shoulder gets caught above the mother’s pubic bone
What is a sign for shoulder dystocia?
retraction of the baby’s head back into the vagina, known as “turtle sign”
What are risk factors for shoulder dystocia?
Gestational diabetes, previous history of the condition, operative vaginal delivery, obesity in the mother, an overly large baby, epidural anesthesia
How would you diagnose shoulder dystocia?
Body fails to deliver within one minute of the head
How would you manage shoulder dystocia?
McRoberts maneuver 00> hyperflexing mother’s legs to the abdomen
If this maneuver does not succeed, an assistant applies pressure on the lower abdomen (suprapubic pressure)
What are the risk factors for the baby after shoulder dystocia?
Brachial plexus injury
Clavicle fracture
What are the risk factors for the mother after shoulder dystocia?
Vaginal or perineal tears, postpartum bleeding
What brachial plexus injury is most commonly the result of shoulder dystocia?
Erb’s palsy
The most commonly involved root is C5
The most commonly involved nerves are the suprascapular nerve, musculocutaneous nerve, and the axillary nerve
The signs of Erb’s palsy include loss of sensation in the arm and paralysis and atrophy of the deltoid, biceps, and brachialis muscles
How does Erb’s palsy present?
The position of the limb, under such conditions, is characteristic: the arm hangs by the side and is rotated medially; the forearm is extended and pronated. The arm cannot be raised from the side; all power of flexion of the elbow is lost, as is also supination of the forearm
How is postpartum haemorrhage defined?
Loss of more than 500 ml or 1,000 ml of blood within the first 24 hours following childbirth
What are the symptoms of postpartum haemorrhage?
Significant blood loss after childbirth, increased heart rate, feeling faint upon standing, increased breath rate
Signs and symptoms of circulatory shock may also include blurry vision, cold and clammy skin, confusion, and feeling sleepy or weak
What are the causes of postpartum haemorrhage?
Causes of postpartum hemorrhage are uterine atony, trauma, retained placenta or placental abnormalities, and coagulopathy, commonly referred to as the “four Ts”:
- Tone
- Trauma
- Tissue
- Thrombin
