Obs And Gynae Flashcards
Describe the HPG axis in the menstrual cycle
GnRH secretion > LH and FSH secretion from anterior pituitary
LH: theca cells = androgen production
FSH: granulosa cells = androgen conversion to oestrogen + inhibin secretion (negative feedback)
Oestrogen + progesterone = negative feedback
High oestrogen alone = positive feedback
Describe the follicular phase (days 1-13) of the ovarian menstrual cycle
15-20 early antral follicles
Day 7: selection of dominant follicle
Day 13: LH surge due to high oestrogen alone - Graafian follicle (secondary oocyte)
Oestrogen rises throughout
Describe ovulation (day 14) in the ovarian menstrual cycle
Graafian follicle ruptures and releases oocyte with antral fluid
Remaining follicular cells begin to produce progesterone, becoming corpus luteum
Describe the luteal phase (day 15-28) in the ovarian menstrual cycle
Corpus luteum produces oestrogen, progesterone (peaks at day 21), and inhibin
Spontaneously regresses after 14 days, allowing LH/FSH to rise again
What happens to progesterone levels due to the loss of corpus luteum
Decrease
Describe the proliferative phase of the uterine menstrual cycle
Endometrial proliferation, spiral arterioles, secretory gland formation
Under the influence of oestrogen
Describe the secretory phase of the uterine menstrual cycle
Glands secrete glycogen, glycoproteins etc
Myometrial contraction inhibited
Under the influence of progesterone
Normal pregnancy term
37 + 0 weeks
Gravidity (G) definition
Number of times a woman has been pregnant regardless of the outcome (includes current pregnancy)
Parity (P) definition
number of times a woman has delivered a foetus with a gestational age greater than 24 weeks, regardless of outcome
Where does fertilisation most often occur in the Fallopian tubes
Ampulla
Describe the four stages of fertilisation
- Capacitation: final stage of sperm maturation
- Acrosome reaction: lytic enzyme release, penetrates oocyte membrane
- Cortical reaction: prevents multiple sperm from fertilising egg
- Syngamy: fusion of pronuclei
Describe the stages of blastocyst implantation at the endometrium
Name the 3 layers of a blastocyst
Describe the formation of the placenta
Starts to form directly after implantation (day 6-7)
Outer trophoblast cells invade into endometrium
By day 14, the cells have invaded into maternal cells, forming chorionic villi
By day 21, foetal blood vessels have grown into the chorionic villi
Which haematological components INCREASE in pregnancy
Plasma volume
Red cell mass
White cell count – neutrophilia
Clotting factors – survival mechanism
Which haematological components DECREASE in pregnancy
Hb concentration – physiological anaemia
Platelet count
Fibrinolysis
What percentage does cardiac output increase during 1st trimester
45%:
• 30% due to increased stroke volume (preload)
• 15% due to increased heart rate
NB: Rises by a further 33% in labour.
• MAP = CO * SVR
(?) What is increased cardiac output caused by in the beginning of pregnancy
Reduced peripheral vascular resistance
Respiratory changes in pregnancy
Minute ventilation rises by 40%
Low paCO2
Renal changes in pregnancy
Sodium retention
Increased renal clearance
Gastrointestinal changes in pregnancy
sphincter relaxation, delayed gastric
emptying, dysmotility
Endocrine changes in pregnancy
prolactin and thyroid hormone increased,
oestrogen and progesterone increase throughout
Uterine hypertrophy changes in weight
60g non-pregnant, 1kg at term
Weeks 1-10 embryonic development
Neural tube closure at 4 weeks
Heartbeat at 4-5 weeks, definitive circulation by 11 weeks
Isolated limb movements at 10 weeks
Week 11-term foetal development
CRL = crown-rump length
Week 12: CRL 56mm, weight 14g (pictured)
Week 16: CRL 122mm
Week 24: CRL 210mm
Surfactant Production 24 weeks
Amniotic fluid
Amniotic cavity adjacent to epiblast of bilaminar disc from day 7.
• Initially collection of extracellular fluid derived from maternal plasma. • Foetal renal function by 22 weeks.
• Mainly foetal urine
• Swallowed by foetus
• Up to 1000ml at term (usually)
Definition of pre eclampsia
new onset hypertension and proteinuria
(2+) after 20 weeks gestation // hypertension plus systemic effect
Pathogenesis of pre eclampsia
abnormal invasion of trophoblast into maternal spiral arterioles
Pathophysiology of pre eclampsia
systemic vasoconstriction = ECLAMPSIA multisystem damage: liver, kidneys, CNS, haematological, placental insufficiency
Risk factors pre eclampsia
nulliparity, twin pregnancy, previous hx,
family hx, obesity, age 40+,etc.
Signs symptoms pre eclampsia
headache, oedema, RFM, hyperreflexia
Investigations pre eclampsia 1st line
PLGF, urinalysis, blood pressure, U+Es, LFTs, FBC
Investigations pre eclampsia 2nd line
2-weekly CTG, umbilical artery Doppler, USS foetus
Management pre eclampsia 1st line
labetalol / nifedipine / methyldopa
Management pre eclampsia 2nd line
delivery (<34 weeks, give MgSO4 and
betamethasone / dexamethasone)
Management high risk pre eclampsia
Aspirin from 12 weeks
Eclampsia definition
Tonic-clonic seizures in presence of pre-eclampsia
Eclampsia management
delivery, magnesium sulfate
HELLP syndrome
Haemolysis, Elevated Liver enzymes, Low Platelets
Management: delivery
DIC management
Platelet and FFP infusion
Pre eclampsia complications
Eclampsia
HELLP syndrome
DIC
Intrauterine growth restriction
Intrauterine foetal death
Renal failure
Acute liver failure
Stroke
Heart failure
Causes of antepartum haemorrhage
Placental Abruption
Placenta Praevia
Vasa Praevia
Cervical Ectropion
50% unexplained
Placental abruption definition
premature separation of placental
bed
Presentation of placental abruption
Acute abdominal pain (but not always)
Contractions
Antepartum haemorrhage (but not always)
“Woody” uterus on palpation
Placental abruption investigations
Bloods, coagulation screen, USS foetus,
CTG monitoring
Management of placental abruption
Expedite delivery (induction or C-Section,
dependant on foetal condition)
Placenta praevia definition
placenta lying in lower segment of the uterus – Grades 1-IV
Presentation of placenta praevia
painless antepartum haemorrhage, soft uterus
Investigations placenta praevia
bloods, coag screen,
USS foetus, CTG monitoring (i.e.
APH investigations).
• Low-lying placenta should be
detected on routine 20 week anomaly scan
• Follow-up TVUSS at 32 weeks
Management placenta praevia
Elective C section
Pelvic girdle components
Sacrum
Coccyx
2 x innominate bones: ilium, ischium, pubis
3 signs of labour
Progressive contraction (3-5 in 10)
Bloody show
Ruptured membranes (waters break)
How long does the latent stage (3cm dilated cervix) of normal labour last?
6-8 hours
How much increase in dilation occurs during the active stage (3cm-10cm dilated)
0.5-1cm per hour
What is the second stage of labour
From full dilation to birth
NB: If you’re having your 1st baby, this pushing stage should last no longer than 3 hours. If you’ve had a baby before, it should take no more than 2 hours
Describe the third stage of labour
Baby delivered
Placenta delivered
Active labour: Within 30 minutes of delivery - Assisted with syntocinon (synthetic oxytocin) IM and gentle cord traction
Describe the movement stages of baby delivery
- Engagement and descent - widest diameter
- Flexion - narrowest diameter
- Internal rotation of head into OA - crowning
- Extension
- Restitution - head aligns with shoulders
- External rotation - shoulders rotate
- Delivery of shoulders - gentle traction
Failure to progress definition
Insufficient rate of dilation / foetal descent
Causes of failure to progress
Power: hypotonic uterine activity (>45s, 3-5 in 10min)
Passage: pelvic dimensions (inlet/outlet)
Passenger: position (rotation), attitude (flexion) and head size
Failure to progress management
Augmentation of labour - ARM, synctinon infusion
Instrumental delivery - forceps or ventouse
Caesarean section
Indications for instrumental delivery
Failure to progress
Fetal distress
Maternal exhaustion
Control of the head in various fetal positions
Given to mothers during an instrumental delivery to reduce infection
Co-amoxiclav
Instrumental delivery risks to mother
Postpartum haemorrhage
Episiotomy
Perineal tears
Injury to the anal sphincter
Incontinence of the bladder or bowel
Nerve injury (obturator or femoral nerve)
Main complication using ventouse method of instrumental delivery
Cephalohaematoma
Main complication of using forceps method of instrumental delivery
Facial nervy palsy
4 Indications for an elective Caesarian section
Previous caesarean
Placenta praevia
Breech presentation
Multiple pregnancy
Categories of emergency C section
Category 1: immediate threat to the life of the mother or baby. [Decision to Delivery] = 30 minutes
Category 2: not an imminent threat to life, but caesarean is required urgently due to compromise of the mother or baby. [Decision to Delivery] = 75 minutes.
Category 3: delivery is required, but mother and baby are stable
Category 4: elective caesarean
Layers of the abdomen dissected in a C section
Skin
Subcutaneous tissue
Fascia / rectus sheath
Rectus abdominis muscles
Peritoneum
Vesicouterine peritoneum (and bladder)
Uterus (perimetrium, myometrium and endometrium)
Amniotic sac
Measures used to reduce the risks in C section
H2 receptor antagonists (e.g. ranitidine) or proton pump inhibitors (e.g. omeprazole) before the procedure
Prophylactic antibiotics during the procedure to reduce the risk of infection
Oxytocin during the procedure to reduce the risk of postpartum haemorrhage
Venous thromboembolism (VTE) prophylaxis with low molecular weight heparin
Shoulder dystocia definition
anterior shoulder of the baby becomes stuck behind the pubic symphysis of the pelvis, after the head has been delivered
Obstetric emergency!
Main cause of shoulder dystocia
macrosomia secondary to gestational diabetes.
Presentation of shoulder dystocia
Turtle neck sign (head is delivered but then retracts back into the vagina)
Failure of restitution
Difficulty delivering head/chin
Complications of shoulder dystocia
Fetal hypoxia (and subsequent cerebral palsy)
Brachial plexus injury and Erb’s palsy
Perineal tears
Postpartum haemorrhage
Management of shoulder dystocia
1st line: call for help/MDT
2nd line: instruct mum to stop pushing + lie flat on the bed
3rd line: McRobert’s + suprapubic pressure + axial traction (90% of cases)
4th line: internal manoeuvres/deliver posterior arm
5th line: all fours, repeat
6th line: episiotomy (enlarge vaginal opening), Zanvanelli (push back for C section), symphsiotomy
McRoberts manoeuvre in shoulder dystocia
Hyper flex ion of the mother at the hip (knee to abdomen) = posterior pelvic tilt = pubic symphysis up and out of the way
Primary postpartum haemorrhage definition
500ml blood loss within 24 hours of vaginal delivery
1000ml blood loss within 24 hours of caesarean section
Secondary post partum haemorrhage definition
From 24 hours to 12 weeks after birth
Classifications of PPH
Minor: 500-1000
Major: 1000-1500
Massive obstetric haemorrhage: 1500+
4 causes of PPH
4 T’s!
Tone - atonic uterus (prolonged labour, macrosomia, twins)
Trauma - genital tract injury
Tissue - retained placenta/membranes
Thrombin - coagulopathy e.g. DIC in pre-eclampsia
Risk factors for PPH
Previous PPH
Multiple pregnancy
Obesity
Large baby
Pre-eclampsia
Management of PPH
Dependent on cause
Fundal massage + syntocinon (40 units) + ergometrine
Rhesus: fluids, oxygen, blood products
Most common site for ectopic pregnancy
Fallopian tube
NB: Isthmus site causes most bleeding
Risk factors ectopic pregnancy
Previous ectopic
Previous PID
Previous surgery to the fallopian tubes
Intrauterine devices (coils)
Older age
Smoking
When does ectopic pregnancy typically present
6-8 weeks gestation
Features of ectopic pregnancy
Missed period
Constant lower abdo pain in the right or left iliac fossa
Vaginal bleeding
Tenderness/guarding
Ectopic pregnancy investigations
Pregnancy test
Transvaginal ultrasound scan
Management of a unruptured ectopic pregnancy
Methotrexate (highly teratogenic) OR laparoscopic salpingectomy (key hole to remove affected fallopian tube) or laparoscopic salpingotomy
Management of ruptured ectopic pregnancy
Laparoscopic salpingectomy / salpingotomy + resuscitation +/- post op methotrexate
Differentials for acute lower abdo pain in young female
Appendicitis
Ectopic pregnancy
Ovarian torsion
Miscarriage
Cyst rupture
PID/tubal abscess
Investigations acute lower abdo pain in young female
Urine pregnancy test
TV USS
I.e. ectopic until proven otherwise
Early miscarriage definition
Spontaneous termination of pregnancy before 12 weeks gestation
Late miscarriage definition
Spontaneous termination of pregnancy between 12 and 24 weeks gestation
Miscarriage gold standard Ix
TV USS
Three key features on TV USS for miscarriage
Mean gestational sac diameter
Fetal pole and crown-rump length
Fetal heartbeat
Management miscarriage less than 6 weeks gestation
Expectant management providing there is no pain or complications or risk factors (eg. Previous ectopic)
No scan needed
Repeat urine pregnancy test after 7-10 days - negative = confirmed
Miscarriage management more than 6 weeks gestation
Early pregnancy assessment unit (EPAU) > TV USS:
Options:
- Expectant management
- Medical management (misoprostol)
- Surgical management
Misoprostol pharmacology
Prostaglandin analogue
Prostaglandins soften the cervix and stimulate uterine contractions
Incomplete miscarriage definition
Retained products of conception remain - risk of infection
Medical or surgical management (evacuation using vacuum aspiration)
Recurrent miscarriage definition
Three or more consecutive miscarriages
Causes of recurrent miscarriage
Idiopathic (particularly in older women)
Antiphospholipid syndrome (hyper coagulable state)
Uterine abnormalities
Chronic disease e.g. diabetes, untreated thyroid disease, SLE (secondary antiphospholipid syndrome)
Antiphospholipid syndrome Ix
Anti-phospholipid antibodies
Antiphospholipid syndrome treatment
Low dose aspirin
LMWH
Legal framework for a termination of pregnancy
1967 abortion act
1990 human fertilisation and embryology act
1990 changes to abortion act
Latest gestational age from 28 weeks to 24 weeks
Medical abortion treatment
- Mifespristone (anti-protestogen) halts pregnancy and relaxes cervix
- Misoprostol (prostaglandin analogue) 1-2 days later - softens cervix and stimulates uterine contractions
NB: rhesus negative women with a gestational age of 10 weeks or above having a medical TOP should have anti-D prophylaxis
Chorionicity definition
Number of placentas
Amnionicity definition in twin pregnancy
Number of amniotic sacs
Significant complication of gestational diabetes
Macrosomia
Neonatal hypoglycaemia
Women with risk factors for gestational diabetes screening test
OGTT at 24-28 weeks gestation
OGTT
75g glucose drink
Blood sugar measured before glucose (fasting) and 2 hours after
Normal results:
Fasting: <5.6 mmol/l
At 2 hours: <7.8 mmol/l
Management for gestational diabetes
Fasting < 7: trial of diet and exercise by 1-2 wks followed by metformin then insulin
Fasting > 7: insulin +/- metformin
Fasting glucose > 6 + macrosomia: insulin +/- metformin
Women with pre-existing diabetes management
5mg folic acid preconception to 12 weeks gestation
Retinopathy screening for diabetic retinopathy
Planned delivery between 37 and 38 + 6 weeks for pre-existing (gestational - up to 40 + 6)
Type 1: sliding scale insulin regime
Neonatal hypoglycaemia - management if glucose falls below 2 mmol/l
IV dextrose of nasogastric feeding
Prophylaxis for VTE starting points in pregnancy (RCOG guidelines)
3 + risk factors: 28 weeks
4 + risk factors: first trimester
Prophylaxis = LMWH e.g. dalteparin
DVT/PE 2a notes
To do: VTE pregnancy diagnosis + management
