INTRO TO OBSTETRICS: General principles, antenatal, intrapartum, postnatal Flashcards
What are the trimesters in pregnancy?
1st trimester = 0-14w
2nd trimester = 14-28w
- 24w = point of viability
3rd trimester = 28-42w
-37-42w = term
What are the stages of labour?
1ST STAGE = Onset of spontaneous, regular, painful contractions until 10cm cervical dilation and full dilation
- LATENT = until 4cm dilation + full effacement, typically 3-8hrs
- ACTIVE = from 4-10cm dilation, typically 2-6hrs
2ND STAGE = Full dilation to delivery of baby
- PASSIVE = 1-2hrs
- ACTIVE = <2hrs
3RD STAGE = Delivery of placenta
- typically <30mins
What is classed as a prolonged second stage?
Nulliparous = >2hrs since onset of active 2nd stage
Multiparous = >1hr since onset of active 2nd stage
Allow an extra hour if epidural analgesia
What are birth options for normal delivery?
Spontaneous vaginal delivery
ELCS (abdominal wall layers inc: skin, subcutaneous tissue, rectus sheath, rectus muscle, parietal peritoneum, uterus inc. visceral peritoneum)
How is difficulty starting labour managed?
Induction of labour
- prostaglandins (pessary/gel)
- balloon catheter
These dilate and ripen the cervix
- then can have ARM
How is difficulty progressing managed?
Augmentation of labour:
- Artificial rupture of membranes (ARM) -> natural release of prostaglandins
- Synthetic oxytocin/syntocinon improves quality of contractions
What options are there for emergency delivery?
Instrumental delivery - ventouse or forceps
Emergency C-section (category 1 within 30mins, category 2 within 75mins)
How can obstetrics management be structured?
Maternal = manage acute medical issue, develop ongoing plan
Foetal = ongoing monitoring for remainder of pregnancy, delivery may be only cure
Labour = timing, mode and interventions to assist delivery
What are RFs and complications of placenta praevia?
Sx = painless, bright red bleeding
RFs = prev. C-sections
Complications = maternal haemorrhage, foetal IUGR
How is placenta praevia diagnosed?
Abdo exam = soft, non-tender uterus, abnormal foetal position
TVUSS = measure distance between placenta and os
How is placenta praevia managed?
MATERNAL:
- admit + observe for 48hrs if stable
- usually manage conservatively until 36w
- consider fluid replacement and blood products for low BP and low Hb, fibrinogen etc.
FOETUS:
- CTG
- monitor for IUGR w/US
- consider steroids (<34w) to enable earlier delivery
DELIVERY:
- C-section preferred mode
- vaginal birth possible if >2cm from os
- consider admission from 34w for major placenta praevia
What are RFs and complications for placental abruption?
Sx = sudden abdominal pain and bleeding
RFs = prior abruptions, pre-eclampsia, cocaine use
Complications = DIC, foetal death (if caused by arterial bleeding), oligohydramnios, IUGR (venous bleeding)
How is placental abruption diagnosed?
ABDO EXAM: woody, tender, enlarged uterus
TVUSS: not diagnostic but rules out praevia
Abruption is a diagnosis of exclusion
How is placental abruption managed?
MATERNAL
- A to E resuscitation
- blood products if severe bleeding or DIC
FOETAL
- CTG
- consider steroids
- delivery if >36w or if distressed <36w
DELIVERY
- c-section if there’s foetal distress
- otherwise, vaginal birth usually preferred
- DIC makes c-sections risky
When do pregnancy-related conditions appear?
Post 20 weeks
- gestational HTN
- pre-eclampsia
- gestational diabetes
Anything before 20w is a chronic condition that will remain after pregnancy
How is hypertension in pregnancy managed?
- Labetalol - alpha and beta blocker, oral or IV (CI in asthma)
- Nifedipine - CCB, oral, safe in asthma
- Methyldopa - alpha 2 agonist, oral or IV
- Hydralazine - direct acting smooth muscle relaxant and vasodilator, oral IM or IV
What is pre-eclampsia?
New high BP diagnosed >20w + clinically significant proteinuria
Sx = headaches, oedema, RUQ pain, visual disturbances, low PLTs
What are RFs for pre-eclampsia?
MODERATE
- 1st pregnancy, multiple pregnancy, FHx, age >40, BMI >35, >10yr pregnancy interval
HIGH
- hypertensive disease in prev. pregnancy, chronic HTN, CKD, autoimmune disease, diabetes
How is the risk of pre-eclampsia reduced?
Give aspirin from 12w onwards if 2 or more moderate RFs OR 1 or more high RFs present
How is pre-eclampsia managed?
MATERNAL
- antihypertensives
- monitor bloods (FBCs, U&Es, LFTs - HELLP is indication for delivery)
- treat eclampsia w/magnesium sulfate (also indication for delivery)
- monitor BP 4x/day whilst in hospital
FOETAL
- weekly USS and doppler to assess for IUGR and abnormal umbilical artery EDF (end-diastolic flow)
- CTG
- consider steroids if early delivery likely
DELIVERY
- consider delivery from 34w onwards
- intrapartum BP and CTG monitoring
- encourage epidural, avoid ergometrine
- c-section if BP uncontrollable
How is gestational diabetes diagnosed?
New diabetes diagnosed >20w
Ix = fasting blood glucose >5.6 or OGTT >7.8
What effects does pregnancy have on pre-existing diabetes?
- increased insulin requirements
- increased risk of hypos
- deterioration of existing complications like retinopathy and nephropathy
What effects does diabetes have on pregnancy?
- miscarriage and stillbirth
- macrosomia and congenital malformations
- pre-eclampsia, infections
- complicated birth, shoulder dystocia
NOTE: complications worse w/pre-existing diabetes vs gestational diabetes
How is diabetes in pregnancy managed?
MATERNAL
- joint diabetes and antenatal clinic
- diabetes treatment (metformin +/- insulin, start insulin straight away if fasting glucose >7)
- renal and retinal screening
- high dose 5mg folate preconception until 12w if pre-existing diabetes
- postnatal follow up
FOETAL
- serial USS for foetal growth and amniotic fluid volume (every 4w from 28-36w GA)
- assessment of cardiac outflow tracts at 20w anomaly scan
DELIVERY
- elective birth between 37-39w
- if mother is on insulin, manage blood glucose during labour w/sliding scale, aiming for blood glucose of 4-7
