Obstetrics Flashcards
pregnancy- when is the window of blastocyst formation and why?
cycle day 20-24- perfect balance of hormones
pregnancy- what happens after blastocyst formation?
blastocyst buries- interstitial implantation
this starts the primary decidual reaction
pregnancy- what basic placental structures form after interstitial implantation?
floating and anchoring villi
pregnancy- what do cytotrophoblast progenitor stem cells differentiate into?
1- terminal differentiation into syncytiotrophoblast
2- extra-villus trophoblasts
3- regenerate new cytotrophoblasts
pregnancy- what are the functions of the extra-villous trophoblasts?
spinal artery remodelling- endovascular invasion of the myometrium
during pregnancy, when does full placental blood flow occur?
week 10-12
during pregnancy, what can poor endovascular remodelling lead to?
reduced fetal O2 and nutrient supply, which results in:
- pre-eclampsia
- intrauterine growth restriction
- preterm birth
- recurrent miscarriage
pregnancy- what is human chorionic gonadotrophin (hCG)?
- hormone secreted from day 6-7 trophoblast cells of the blastocyst
- promotes maintenance fo corpus luteum
- maintains production of oestrogen and progesterone
where is progesterone produced?
up to week 7/8- corpus luteum
after this it is made in the placenta
what are the functions of progesterone in pregnancy?
- prepare uterus for implantation
- makes cervical mucous thick and impenetrable to sperm after fertilisation
- decrease immune response- allows pregnancy to occur
- decreases contractility of uterine smooth muscle to prevent pre-term labour
what does progesterone inhibit during pregnancy?
lactation
after delivery, falling progesterone levels triggers milk production
what is the function of human placental lactogen (hPL)?
- mobilises glucose from fat
- insulin antagonist to facilitate energy supply to foetus
- converts mammory glands into milk-secreting tissue
what is the function of prolactin?
milk production
what is the function of oxytocin?
milk ejection reflex
what happens to maternal glucose levels during the early stages of pregnancy?
low- due to fat deposition and glycogen synthesis
what happens to maternal glucose levels during the late stages of pregnancy?
high
alongside maternal insulin resistance- ensures glucose sparing for foetus
what happens to maternal insulin levels throughout pregnancy?
rise until week 32
hPL then induces insulin resistance
what immunity changes occur after fertilisation?
increases in GF’s, proteolytic enzymes and inflammatory mediators to facilitate implantation
why is blastocyst implantation not rejected?
change in self: non-pattern recognition molecules (HLA and MHC)
Why are syncytiotrophoblasts and extra-villus trophoblasts not rejected?
- Syncytiotrophoblast has no self:non-self markers
- extra-villus trophoblast has modified self:non self markers
what happens to the T helper ratio during pregnancy?
pregnancy- more Th2 (in ‘normal’ physiology, Th1 and Th2 are balanced)
what are the functions of the following antibodies in pregnancy
IgA IgD IgE IgG IgM
IgA- secreted in breast milk
IgD- on B-cell membranes
IgE- mast cells (anaphylaxis)
IgG- only one that crosses placenta
IgM- early antibody
explain the pathophysiology of Rhesus disease
- haemolytic disease of new born
- Rh -ve mother (dd) and Rh +ve father (Dd or DD)
- sensitisation in first pregnancy igM
- rapid response by IgG of subsequent pregnancy
what is the definition of a normal pregnancy and birth?
- term- 37-42 weeks
- spontaneous onset
- infant born spontaneously in vertex position
birth occurs without:
- induction of labour
- spinal/ epidural/ general analgesia
- forceps/ ventrose delivery
- caesarean section/ episiotomy
what occurs in each of the 3 stages of labour (generally)?
1st- contractions- has two phases- early labour (cervix gradually effaces and dilates) and active labour (cervix dilates rapidly and contractions are longer, stronger and closer together)
2nd- fully dilated, ends with birth of baby
3rd- right after birth, ends with delivery of placenta
what are the 3P’s of pregnancy?
Power- contractions need to be strong enough
Passage- pelvis- anterior-posterior diameter and transverse diameter
Passenger- baby needs to be in correct position
describe the landmarks of the baby’s head felt on vaginal examination to assess the baby’s position
- attitude- how much neck is flexed (ideally is well flexed). can be deflexed- brow presentation (extended to 90’) or face presentation hyperextended to 120’)
- position- OT (occipito-transverse), OA (occipito-anterior)
- size of head- head compressed through pelvis (moulding), swelling causes during delivery (caput)
how long on average is the first stage of pregnancy?
5-12= multiparious
8-12- primiparous
describe the early/ latent phase of the first stage of labour
- irregular, painful contractions
- ‘show’- plug of cervical mucus and blood
- cervix is effacing and thinning
- dilates to 4cm
what is engagement?
how far above the pubic symphysis the babies head is
3/5 of the head within pelvic brim is classed as engaged
what is presentation?
anatomical part of the foetus which presents itself first through birth canal
what is ‘lie’ during labour?
relationship between long axis of fetus and long axis of the uterus
what is ‘station’ during labour?
relationship between the lowest point of presenting part and the ischial spines
describe the active phase of labour (2nd)
- further dilation from 4cm (0.5cm each hour)
- 3-4 regular contractions per hour
- vaginal exam every 4 hours to assess degree of dilation
- oxytocin- syntocinon relationship induces labour
how is pain (generally) managed in labour?
- psychological- relaxation, hypnosis
- sensory methods- hydrotherapy, posture
- birth environment
- complementary - message, aromatherapy
- pain relief mediations
what 3 types of pain relief medications are commonly used in labour?
- entonox
- opiates- morphine. pethidine
- epidural
what is entonox and what are side effects of it?
- used in labour- ‘gas and air’
SE- nausea and vomiting
what opiates are used in labour and what are some maternal and fetal side effects?
- pethidine/ morphine
- maternal SE- euphoria/ dysphoria, nausea/ vomiting, increased length of 1st and 2nd stage of labour
- fetal SE- respiratory depression, diminishes breath seeking/ breast feeding behaviours
what are some maternal and fetal side effects of epidurals?
- maternal- increased length of 1st and 2nd stage, increased incidence of malposition, loss of mobility, loss of bladder control, hypotension, pyrexia
- fetal- tachycardia, diminishes breast feeding behaviour
describe the initial transition stage of the second stage of labour
- SROM- spontaneous rupture of membranes
- irritable, anxious, distressed
- start to feel pressure
- contractions can slow/ stop
- support/ reassurance required
describe the second stage of transition during labour
- full dilatation- 10cm
- externally- head visible
- spent bearing down
in what timeframe would you:
- suspect delay
- diagnose delay
- expect baby to be born
in primigravid women
- suspect delay- 1 hour
- diagnose delay- 2 hour
- born- within 3 hours of pushing
in what timeframe would you:
- suspect delay
- diagnose delay
- expect baby to be born
in multiparous women
- suspect delay- 30 mins
- diagnose delay- 1 hour
- born within 2 hours of pushing
what happens in the 3rd stage of labour?
- pushing out placenta
- physiological management- blood less
- active management- oxytocin
function of relaxin during labour
- released from placement, membrane surrounding baby and uterine lining
- softens ligaments and cartilages of pelvis so it can expand
- helps cervix loosen and soften
- makes baby’s body more flexible and allows head to mould
function of oxytocin during labour
- stimulates uterine contractions during orgasm and childbirth
- large amounts released when cervix is opened, trigging fetal ejection reflex
- contracts uterus post-birth to deliver placenta and limit bleeding
functions of prostaglandins during labour
- ripens cervix and causes it to begin process of thinning and opening
- stimulates uterine contractions
what are the 5 types of malpresentation during pregnancy?
- breech
- occipitoposterior position
- face presentation
- brow presentation
- transverse lie
causes of a breech presentation
- idiopathic
- uterine abnormalities
- prematurity
- placenta previa
- oligohydramnios
- foetal abnormalities- hydrocephalus
how can a breech presentation be reversed?
external cephalic version
what are the complications of an external cephalic version?
- placenta previa
- APH
- ruptured membranes
how is a breech presentation diagnosed?
ultrasound
what are the 3 types of breech presentation?
frank breech
complete breech
footling breech
what is a frank breech?
where the hips are flexed and the legs are extended
what is a complete breech?
hips and knees are flexed and the feet are below the level of the foetal buttocks
what is a footling breech?
where one or both feet are presenting as the lowest part of the foetus
which breech presentation is associated with the highest risk of cord prolapse?
footling breech
there is nothing to act as a plug over the cervix if the membranes rupture
what mode of delivery is most appropriate for a breech presentation?
- vaginal delivery has a risk of foetal hypoxia and birth trauma
- planned C-section
how is an occipitoposterior position diagnosed?
antenatally via palpation
vaginal examination
why is labour prolonged in occipitoposterior position?
because of the degree of rotation needed, so adequate analgesia and hydration are required
describe a face presentation and the method of delivery
- occurs by chance- head extends rather than flexes as it engages
- early vaginal examination- nose and eyes may be felt
- forceps delivery
describe a brow presentation and the management of it
- head is between full flexion and full extension- can revert to either
- vaginal delivery NOT possible !
- delivery by LSCS
what is an LSCS delivery?
lower segment caesarean section
how is a transverse lie antenatally diagnosed?
- ovoid uterus wider at the sides
- lower pole is empty
- head lies in one flank
- foetal heart heard in variable positions
what are the most common reasons for inducing labour?
- prolonged pregnancy
- premature rupture of membranes
- diabetic mother >38 weeks
- rhesus incompatibility
what is the Bishop score?
used to assess if induction is required
- score <5= unlikely to start without induction
- score >9= likely to start spontaneously
what 5 factors are included within the bishop score?
- cervical dilation (cm)
- length of cervix (cm)
- station of head (cm above ischial spines)
- cervical consistency
- position of cervix
in the bishop score, each factor has a score of 0,1 or 2.
for cervical dilation, state what each score implies
0= 0cm
1= 1-2cm
2= 3-4cm
in the bishop score, each factor has a score of 0,1 or 2.
for the length of the cervix, state what each score implies
0= >2cm
1= 1-2cm
2= <1cm
in the bishop score, each factor has a score of 0,1 or 2.
for ‘station of head’ , state what each score implies
0= 3cm above ischial spines
1= 2cm above ischial spines
2= 1cm above
in the bishop score, each factor has a score of 0,1 or 2.
for cervical consistency, state what each score implies
0= firm
1= medium
2= soft
in the bishop score, each factor has a score of 0,1 or 2.
for position of cervix, state what each score implies
0= posterior
1= middle
2= anterior
what must be checked prior to induction?
- lie and position of foetus
- volume of amniotic fluid
- tone of uterus
- ripeness of cervix
what are contra-indications for induction?
- severe degree of placenta praevia
- transverse fetal lie
- severe cephalopelvic disproportion
- cervix <4 on bishops score
what is the induction procedure?
- membrane sweep
- prostaglandin gel or pessary high in vagina (misoprostol)
- amniotomy- ROM
- Oxytocin/ syntocinon infusion (post ROM)
What is cardiotocography?
electronic fetal monitoring for risk factors
what is a normal CTG?
- HR 110-160
- variability of 5bpm
- no decelerations
- accelerations present- reassuring when baby is moving
on CTG, what would a heart rate over 160 indicate?
maternal pyrexia
chorioamnionitis
hypoxia
prematurity
on CTG, what would a heart rate under 100 indicate?
increased foetal vagal tone
maternal beta blocker use
on CTG, what would a loss of baseline variability inicate?
prematurity/ hypoxia
on CTG, what would late deceleration indicate?
foetal distress- asphyxia/ placental insufficiency
on CTG, what would variable decelerations indicate?
cord compression
what mnemonic is helpful for interpreting CTG’s?
DR C BRAVADO
DR- Define risk- why are they having it? (e.g pre-eclampsia)
C- Contractions (5 in 10 mins)
BRA- Baseline rate should be 110-160bpm
V- Baseline variability
Normal = 5-25 bpm
Reduced = <5bpm
A- Accelerations
Rise by 15 beats for more than 15 seconds. Should be 2 separate accelerations every 15 mins
D- Decelerations
Reduction of 15 beats for at least 15 seconds
Late decelerations = sign of slow recovery hypoxia
O- Overall Impression
Terminal Bradycardia = <100bpm for >10 mins
Terminal Deceleration = HR drops and does not recover for more than 3 minutes
These make up a ‘pre-terminal’ CTG and indicators of emergency C-section
what is hyperemesis gravidarum?
vomiting in early pregnancy, starts from 4-10 weeks and ends by week 20
associated with WL of more than 5% body mass and ketosis
clinical features of hyperemesis gravidarum
- persistent vomiting
- > 5% weight loss
- dehydration
TRIAD OF:
- > 5% weight loss
- electrolyte imbalance
- dehydration
(plus vomiting)
how is hyperemesis gravidarum managed?
- mild-moderate- reassurance, avoid fatty foods, avoid large volume drinks
- severe- admissions and antoemetics
what anti-emetics are used in the treatment of hyperemesis gravidarum?
- dopamine antagonist- metoclopramide
- phenothiazines- prochloperazine
- ondansteron
complications of hyperemesis gravidarum
- Wernicke’s
- mallory-weiss tear
- pre-term baby
what is puerperal pyrexia?
defined as a temperature of >38’c in the first 14 day following delivery
causes of puerperal pyrexia
endometritis
UTI
wound infection
mastitis
VTE
risk factors for VTE in pregnancy
- age over 35
- BMI >30
- parity >3
- immobility
- FH
- smoker
- varicose veins
- pre-eclampsia
what is the leading cause of morbidity and mortality in pregnancy in developed countries?
VTE
preventable- includes ,DVT, PE
when are VTE risk assessments done?
- booking
- antenatal admission
- labour
- postnatally
what are some indications for LMWH thromboprophylaxisis and compression stockings in pregnancy?
- risk factors of VTE present
if required, LMWH must be given until 6 weeks postpartum
if a pregnant/ post partum lady collapses what is the immediate concern?
PE
investigations in a suspected VTE during pregnancy
- FBC, U&E, LFT, clotting screen
- if suspected PE- ABG, ECG, CXR
imaging:
- DVT- duple US
- PE- CXR, duplex us
what is anaemia in pregnancy defined as?
HB <105g/l
risk factors for anaemia during pregnancy
- starting pregnancy anaemic
- frequent pregnancies
- twin pregnancy
- poor diet
what antenatal screening is done for anaemia?
- Hb estimation at booking and at 28 weeks
black patients- must check sickle cell
risk factors for group B strep infection?
- prematurity
- prolonged ROM
- previous group B strep sibling
- maternal pyrexia
group B strep- if a patient is isolated during labour what should be given?
IV benzyl penicillin to reduce neonatal transmission
clinical features of group b strep infection in pregnancy
- UTI- frequency, urgency, dysuria
- chorioamnionitis- fever, foul discharge, tachycardia
- endometritis- fevers, lower abdo pain, intermenstrual bleeding, foul discharge
symptoms of measles in pregnancy
fever
generalised maculopapular, erythematous rash
Koplik’s spots
cough
coryza
how is rubella spread?
respiratory droplets
features of rubella
Cataracts 8-9 weeks
Deafness 5-7 weeks
Cardiac lesions 5-10 weeks
- Cerebral Palsy
what congenital defects are associated with cytomegalovirus?
IUGR microcephaly hepatoslenomegaly jaundice chorioetinitis
later- motor and cognitive impairment
what are the symptoms of toxoplasmosis?
similar to glandular fever- fever, rash and eosinophilia
cause and treatment of toxoplasmosis
cause- raw meat/ cat faeces
tx- pyrimethamine + sulphadiazine + spiramycin
how is parvovirus B19 spread?
DNA virus
respiratory droplets
4-20 day incubation period
what syndrome may occur in pregnancy with Parvovirus B19?
slapped cheek syndrome
what are the consequences to the foetus of Parvovirus B19 infection?
- foetal suppression of erythropoiesis
- cardiac toxicity- leading to cardiac failure
what should you give to a mother with hepatitis B?
- Screen all mothers
- give immunoglobulin and vaccinate babies of carriers and infected mothers at birth
what should be done if a pregnant mother develops chickenpox near delivery?
- aim for delivery after 7 days
- give baby varicella immune immunoglobulin at birth
- monitor for 28 days
- if baby develops chickenpox- treat with acyclovir
features of foetal varicella syndrome
- skin scarring
- eye defects
- neurological abnormalities
what is gonococcal conjunctivitis and what are the features of it?
- occurs within 4 days of birth
- purulent discharge and lid swelling
how should infants born with gonorrhoea be managed?
cefotaxime and chloramphenicol
what investigations must be done in an infant with jaundice?
- LFT’s
- urine dip- bile
- serology
- HBsAG- Hep B surface antigen
when is obstetric cholestasis (intrahepatic cholestasis of pregnancy) typically seen and what are some features of it?
- 3rd trimester
- jaundice, pruritis of palms and soles, NO RASH, worse at night, raised bilirubin
how is obstetric cholestasis managed?
- ursodeoxycholic acid
- symptoms resolve upon delivery
complications of obstetric cholestasis
stillbirth
preterm labour
meconium
foetal distress
when does acute fatty liver of pregnancy occur and what are some features?
- rare- occurs in 3rd trimester
- very serious !
- jaundice, abdo pain, malaise etc, hypoglycaemia, pre-eclampsia
complications of acute fatty liver of pregnancy
hepatic steatosis
coma, death
investigations and management of acute fatty liver of pregnancy
- high ALT
management- delivery is definitive management
where do the majority of ectopic pregnancies lie?
97%- fallopian tubes- typically the ampullary (most common) or isthmic portions
what is an ectopic pregnancy?
pregnancy that occurs anywhere outside the uterus
risk factors for an ectopic pregnancy?
- IVF
- age
- PID
- Previous ectopic
- smoking
- adhesions from infection and inflammation from endometriosis
- previous tubal surgery
clinical presentation of an ectopic pregnancy
- abdo/pelvic pain and tenderness
- amenorrhoea- 6-8 weeks
- vaginal bleeding
- dizziness, fainting, syncope
- rebound tenderness
- shoulder tip pain- diaphragmatic irritation from blood if ruptures
differential diagnosis of an ectopic pregnancy
threatened miscarriage
appendicitis
bowel ischaemia
diagnostic tests and results in an ectopic pregnancy
- pregnancy test- no rapid decline of bhCG
- transvaginal USS
- empty uterus and positive pregnancy test
treatment of an ectopic pregnancy
- medical- if no complications- single dose methotrexate
- surgery- salpingectomy, salpingotomy
side effects of methotrexate treatment (in an ectopic pregnancy)?
conjuctivitis
stomatitis
diarrhoea
abdo pain
what must be given/ used alongside methotrexate?
contraception- methotrexate is teratogenic
what is a molar pregnancy?
gestational trophoblastic disease
- molar pregnancy- non-viable fertilised egg= implants into uterus- will not come to term
aetiology of a complete molar pregnancy
all genetic material comes from father- so empty oocyte is fertilised
sperm+ empty egg
aetiology of a partial molar pregnancy
- trophoblast cells have 3 sets of chromosomes (triploid)
- 2 sperms fertilise ovum at same time
- 2 sperms plus one egg
what follows a molar pregnancy in 2-3% of cases?
choriocarcinoma
risk factors for a molar pregnancy
- age <16 or >45
- multiple pregnancies
- previous molar pregnancy
- women with menarche over the age of 12
- OCP
- asian
what is an invasive mole?
when. complete mole invades the myometrium
how does a molar pregnancy present clinically?
- first half of pregnancy- vaginal bleeding
- uterine evacuation- 10 weeks of gestation
- exaggerated Sx of pregnancy- hyperemesis gravidarum
- pre-eclampsia
- unexplained anaemia
how is a molar pregnancy diagnosed?
- bhCG- very high levels in blood and urine
- history
- USS- ‘snowstorm appearance’ in 2nd trimester
treatment of a molar pregnancy
- urgent referral
- suction curettage and HCG monitoring
- chemo- cisplatin
- effective contraception- ensure female does not get pregnant until hCG levels have been normal for 6 months
- ERPC- evacuation of retained products of contraception