Obs + Gynae II Flashcards
(119 cards)
Crown rump length required for diagnosis of miscarriage
> 7mm
At <7mm, may be too early to tell if pregnancy is viable but very early, or if it is non-viable
Foetal heartbeat expected once CRL >7mm
Repeat USS in potential miscarriage
If CRL <7mm without foetal heartbeat, scan repeated at least one week later to ensure heartbeat develops
CRL >7mm, without a foetal heartbeat, scan repeated one week later to confirm a non-viable pregnancy
If mean gestational sac diameter >25mm without a foetal pole, scan repeated after one week to confirm an anembryonic pregnancy
Measurements relevant in miscarriages
CRL = 7mm, foetal heartbeat expected once CRL >7mm
Mean gestational sac diameter = 25mm, foetal pole expected once diameter >25mm
Investigation/management in miscarriage <6 weeks
USS not useful, perform repeat urine pregnancy test after 7-10 days. Negative –> confirms miscarriage
Expectant management, unless bleeding continues, or pain occurs, or risk factors e.g. previous ectopic
Follow-up for low-grade cervical intraepithelial neoplasia (CIN 1)
Screen again at 12 months in the community
Most common type of vaginal cancer
Overall = secondary (metastatic cancer), usually from cervix, ovary or endometrium
Prumary cancer = squamous cell carcinoma
Features of vaginal cancer
Post-coital bleeding is common
May be followed by an offensive watery discharge
Follicular phase of menstrual cycle
Granulosa cells surround oocytes –> follicles
FSH stimulation –> further development of follicles
Granulosa cells secrete oestrogen as follicles grow –> negative feedback –> reduced FSH/LH secretion
Oestrogen –> cervical mucus is more permeable
Dominant follicle forms
LH surge –> dominant follicle release ovum
Luteal phase of menstrual cycle
After ovulation, follicle collapses –> corpus luteum –> secretes progesterone –> maintains endometrial lining, thickens cervical mucus
Also secretes some oestrogen
What happens to the corpus luteum when fertilisation occurs
Syncitiotrophoblast of the embryo secretes hCG –> maintain corpus luteum –> produces progesterone + oestrogen
What happens if no fertilisation occurs in menstrual cycle
No hCG production –> corpus luteum degenerates –> stops producing oestrogen + progesterone
This causes endometrium to break down + menstruation occurs
Stromal cells of endometrium release prostaglandins –> encourage breakdown of uterus + contraction
LH + FSH levels rise
Process of foetal descent through birth canal
Descent
Engagement (<2/5 palpable)
Flexion
Internal rotation
Crowning
Extension of presenting part
External rotation of head
Delivery (of shoulders and rest of body)
Management of asymptomatic bacteriuria in pregnancy
Confirm presence of bacteria with second culture (contamination of first sample possible)
Offer an immediate antibiotic prescription, taking into account urine culture + susceptibility
e.g. Nitrofurantoin (avoided at term), amoxicillin (if results available + susceptible), cefalexin
Diagnosis of polyhdramnios
Amniotic fluid index >24cm (or 2000ml+)
AFI >95th centile for gestational age
Diagnosis of oligohydramnios
Amniotic fluid index <5cm (or <200ml)
AFI <5th centle for gestational age
Timings of amniotic fluid
Increases steadily until 33 weeks gestation
Plateaus from 33-38 weeks
Declines –> approx 500ml at term
Causes of polyhdramnios
Idiopathic = 50-60% cases
Conditions preventing foetus from swallowing
Duodenal atresia
Anaemia
Foetal hydrops
Twin-to-twin transfusion syndrome
Genetic or chromosomal abnormalities
Macrosomia
Maternal diabetes
Maternal use of lithium
Viral infections
Management of polyhydramnios
No medical intervention required for majority
Aminoreduction if severe maternal symptoms (risk of infection + placental abruption)
Indomethacin –> enhance water retention –> reduce foetal output (premature closure of PDA so not used beyond 32 weeks)
Examine baby if idiopathic
Risks of polyhydramnios
Malpresentation
–> higher risk of cord prolapse
Postpartum haemorrhage
Causes of oligohydramnios
Preterm prelabour rupture of membranes
Placental insufficiency (blood flow to brain –> reduced foetal urine output)
Renal agenesis (Potter’s syndrome)
Non-functioning foetal kidneys
Obstructive uropathy
Genetic/chromosomal abnormalities
Viral infections
Management of oligohydramnios
Depends on underlying cause
P-PROM –> induction of labour if relevant, steroids for foetal lung development, antibiotics for infection
Placental insufficiency –> deliver before 36-37 weeks
Complication of oligohydramnios
Foetal muscle contractures due to inability to move limbs in utero
Points to remember for epilepsy in pregnancy
Risk of uncontrolled epilepsy > risk to foetus
Take 5mg folic acid per day prior to conception –> 12 weeks (risk of neural tube defects)
Aim for monotherapy
Epilepsy medications in pregnancy
Avoid sodium valproate (NTD)
Carbamazepine is least teratogenic of older antiepileptics
Phenytoin –> risk of cleft palate, given vitamin K in last month of pregnancy to prevent clotting disorders in newborn
Lamotrigine –> seems safe, may need increased dose
Most anti-epileptics safe in breastfeeding