Obstetrics Flashcards
Fertilisation to implantation?
What is blastocyst?
Fertilisation in ampulla Day 1 - fertilised Day 5 - blastocyst Day 5-8 - blastocyst attaches to endometrium Day 12 - implantation complete
Blastocyst:
- divided into 2 cell masses
- inner = embryo
- outer = trophoblast (initial progesterone and implantation, goes on to produce placenta
Placenta:
- components?
- when is it fully functional?
- functions?
- maternal cells and trophoblast cells
5 weeks
Functions:
- hormone secretion - progesterone and hCG
- gas exchange
- nutrient exchange - Ca and Fe are only 2 which go unidirectional from mother to baby
Changes and functions during pregnancy:
- hCG?
- progesterone?
- oestrogen?
hCG:
- peaks at 10 weeks then reduces
- stimulates corpus lute to produce progesterone
- ensures early nutrition of embryo
Progesterone:
- initially produced by corpus luteum then placenta
- levels steadily rise through pregnancy
- prepares and maintains endometrium
- later, decreases uterine contractions
Oestrogen:
- principal site of production is placenta
- levels steadily rise through pregnancy
- enlarges uterus, develops breasts, relaxes pelvic ligaments
E3 - indicator of foetal viability
E4 - only produced through pregnancy
CVS changes in pregnancy?
CO increases from week 6, peaks at week 24, decreases then increases again in labour
SV up 30%, HR up 15% & cardiac output up 40%
Systolic BP is unaltered
diastolic BP is reduced in the 1st and 2nd trimester, returning to non-pregnant levels by term
IVC compression causes ankle oedema, supine hypotension and varicose veins
Resp changes in pregnancy?
Pulmonary ventilation up 40%, tidal volume up 200ml
O2 requirements up 20% - over breathing causes low CO2
-> this may cause sense of dyspnoea, accentuated by diaphragm compression
Metabolic changes in pregnancy?
BMR up 15%, probably due to thyroid or adrenalcorticotrophic hormones
Haem changes in pregnancy?
Blood volume up 30% but cells less than plasma, causing relative anaemia
Rise in fibrinogen and clotting factors, increased DVT risk, esp with IVC compression
Lower platelet count
Urinary changes in pregnancy?
GFR, renal blood flow increased
Urinary protein loss increased
Salt and water reabsorption increased due to increased sex steroid levels
Calcium changes in pregnancy?
Significantly increased requirements, esp in 3rd trimester with lactation
Ca is transported to foetus through placenta
Serum levels of Ca and PO4 drop due to fall in protein, but total ionised calcium remains the same
Gut absorption of Ca increases significantly due to increased VitD activity
Uterine changes?
100g -> 1100g
Hyperplasia and later hypertrophy
Increased cervical ectropion and cervical discharge
Braxton Hicks - practice contractions late in pregnancy
Hormones in labour?
Ferguson reflex?
Progesterone - prevents contractions
Oestrogen - stimulates contractions
Oxytocin - stimulates contractions and prostaglandin release
PG - increases contractions
Ferguson reflex:
- positive feedback loop
- stretch of cervix causes release of oxytocin which causes further stretching of cervix
Gestational diabetes diagnosis?
Management?
If metformin not tolerated?
Aims once on meds?
Diagnosis:
- fasting 5.6+
- 2 hours OGTT 7.8+
Management:
- Fasting 5.6-7: diet/exercise
If no better after 1-2 weeks - metformin
if still no improvement, short-acting insulin
- If 7+ at diagnosis, insulin straight off the bat
Glibenclamide
Aims:
- fasting 5.3
- 1 hour 7.3
- 2 hour 6.4
When should foetal movements be felt?
What is reduced foetal movements?
Ix?
24 weeks - if not then refer to foetal medicine unit
- Usually start at 18-20 weeks and gradually increase to 32 weeks then plateau
- No definition but generally <10 movements in 2 hours past 28 weeks
Ix:
- handheld doppler 1st line
- If <28 weeks, just confirm presence of heartbeat, if not present then immediate referral
> 28 weeks:
- If present on doppler, do CTG for 10 mins
- If not present on doppler or still concern after CTG, do immediate USS
Supplements in pregnancy?
VitD 400IU throughout pregnancy
Folic acid for first 12 weeks
400mcg
5mg if:
- obese >30 BMI
- FHx neural tube defect
- coeliac, diabetes, thalassaemia
- alcohol excess, phenytoin, methotrexate
Variable decelerations means?
Indicates?
Rapid fall in foetal HR with variable recovery phase
Indicate cord compression and potential cord prolapse
- Elevate presenting part either manually or by filling urinary bladder
- Get on all fours
- Consider tocolysis and prep for C-sec
Management of placental abruption <36 weeks and >36 weeks?
<36 weeks:
- foetal distress on CTG - immediate C-sec
- No foetal distress - admit for tocolysis and steroids
> 36 weeks
- immediate Csec
What is pre-eclampsia?
Features of severe?
- RF?
- New onset HTN >140/90 past 20 weeks gestation
Plus one of: - proteinuria (ankle oedema)
- Organ involvement (renal, liver, haem, neuro, uteroplacental dysfunction)
Severe:
- Hypertension >160/110
- protein ++/+++
- Headache
- visual disturbance
- papilloedema
- RUQ/epigastric pain
- Hyperreflexia
- HELLP
RF:
- HTN normally of in prev preg
- CKD
- Diabetes
- autoimmune
- Primi
- > 40
- Preg interval 10 years
- BMI >35
- FHx
- Multiple preg
How to prevent pre-eclampsia?
Referral?
Management of pre-eclampsia?
75mg aspirin from 12 weeks on if 2+ RF
- Emergency secondary care assessment in any suspected
- If BP >160/110 usually admitted for observation
Drugs:
- labetalol 1st line (CI asthma)
- Nifedipine 2nd line
- Hydralazine
- Methyldopa (CI depression)
Fluid restriction may be
What is HELLP?
Management?
Presents with nausea, vomting, RUQ pain in 10-20% with severe pre-eclampsia
Haemolysis
Elevated liver enzymes
Low platelets
Delivery
What is eclampsia?
Management and comps?
How long treat for?
Seizures due to pre-eclampsia
Management:
- Magnesium both prevents and treats seizures
- Monitor urine output, resp rate and O2 sats
- Calcium glutinate treats Magnesium induced resp depression
- treat for 24 hours after delivery or after last seizure
Management of shoulder dystocia?
- McRobert’s - maximally flex and abduct hips
- Suprapubic pressure in McRobert’s
- Episiotomy (may help but allows extra room for internal manoeuvres)
- Rubin, push on posterior shoulder
- Wood’s screw, zavanellib, symphesiotomy, emergency CS
Placenta praaevia?
Normally picked up on 20 week scan
If low lying, repeat USS at 34 weeks
Suspect if painless vaginal spotting that starts >30 weeks and increases in frequency and volume
TVUS
CS to prevent labour
What is routinely offered in screening at booking scan?
- anaemia
- bacteriuria
- Blood group, rhesus, ABO
- Trisomy
- Foetal anomalies
- HepB
- HIV
- Syphilis
- neural tube defects
- RF for pre-eclampsia (diabetes, CKD, autoimmune etc)
What is placenta accreta?
RF?
Small print but different types?
Defect in decidua basalis causing placenta to attach to myometrium, risk of significant PPH as it doesn’t detach properly
Decidua basalis is the endometrial cells of the placenta, normally there is a fibrinous layer separating this from normal uterine wall
RF:
- previous CS
- placenta praevia
Accreta - chorionic villi attach to myometrium instead of decidua basalis
Increta - Chorionic villi invade myometrium
Percreta - Chorionic villi invade through perimetric