Obs&Gynae Flashcards
Based on Dr Clarke
What’s the best way to measure a baby’s gestational age Measuring what?
Doing an ultrasound at 12/40. Measuring CRL = Crown rump length
Define Nulliparous, multiparous and primigravid
Primigravid first ever pregnancy G1P0 Nulliparous, no deliveries of babies >24/40 Multiparous, has had deliveries of a baby(ies) >24
Whats parity and gravity?
Parity is the number of babies delivered older than 24/40 Gravity is how many times a woman has been pregnant
What is Nagele’s rule?
LMP (First day) - 3 months +1 year +7 days
When are screening tests offered?
Booking in 1st trimester: USS and hCG and PAPP-A @ 10-13 weeks and detection rate 85% (dec. to 80 after) Late bookers: Quadruple testing (14-20) -> AFP, hCG, Inhibin A, unconjugated oestriol
Which disorders is AFP raised in?
Down’s, spina bifida, liver condition
What happens when the down’s screen is positive?
Amniocentesis (15+w and lower risk)/chorionic villous sampling (11-14w) 1 in 9 have Down’s
Risks of Breech presentation?
Cord prolapse, difficulty delivering head, fetal hypoxia , increased fetal morbidity and mortality
Describe external cephalic version
Uterine relaxants given, Fetal HR monitored. 50% success rate. Emergency CS in 1:200 cases.
CIs to external cephalic version
Previous CS, <37w gestation, Placenta praevia, Fetal/uterine abnormality, multiple pregmnancy
Reasons for large foetus during dating scan?
Wrong dates, big baby (macrosomia), Poluhydramnios or both
Detection of Polyhydramnios (PH)
Inc. symphysiofundal height, tense cystic uterus (fetal parts hard to feel), Amniotic fluid index, Pool depth >18 indicates PH
Causes of PH
Idiopathic in 60%, Maternal (Diabetes, infection) in 20 and Fetal in 20% of cases
Mechanisms of PH
Swallowing probs (upper GI atresia, anencephaly) Polyuria in maternal DM HF due to structural defect Anaemia/HF - Rh Immunisation, Parvovirus Twin twin transfusion syndrome (1 HF)
Risks of PH
Placental abruption Pretty unusual lie Premature labour Prolapse of cord Postpartum haemorrhage Perinatal mortality
Stages of labour
First - from onset of painful contractions to full dilatation Latent -> up to 4cm Active -> 4-10cm Takes 5-8hrs multi < primi Second - From full dilatation to delivery - up to 1hr in multi, 1-2 hrs in primi Third - from delivery of infant to delivery of placenta -up to 30 min
Causes of failure to progress in 1st stage
Epidural, abnormal presentation, dehydration, stress, Primiparous
7 stages of Mechanism of labour and delivery
Every - Engagement in transverse position
Decent - Descent of head into pelvis
Female - Flexion
In - Internal rotation of head into pelvis
England - Extension of head during delivery
Rules - Restitution ie external rotation
Lovingly - Lateral Flexion of head to deliver shoulders
4Ps main indicators for induction
Post-dates (41-42 weeks) Pre-labour rupture of membranes (inc infection risk) PROM Pre-eclampsia Plus diabetes
What is membrane sweeping
Finger passed between cervix and membrane, thought to invoke hormone regulation; may help avoid induction
3 stages of induction
Stage 1: Ripening of cervix - using Prostin Pessaries - soften and shorten cervix and cause uterine tightening Stage 2: Amniotomy - artificial rupture of membranes with amnihook Stage 3: Intravenous oxytocin to generate uterine contractions (Syntocinon) - 3-4 strong contractions/10min
How do you counteract Uterine Hyperstimulation
with Terbutaline - beta adrenergic receptor antag. which relaxes myometrial smooth muscle and opposes Oxytocin.
Treatment for dysmenorrhea? and for heavy bleeds?
Mefenamic Acid, transexamic acid
Indicate the approximate time for the following Anomaly Scan Dating Scan Rhesus Immunisation Screening Oral Glucose tolerance test for @risk mom Onset of Gestational HTN Quadruple screening test for downs Combined screening test for Downs
Anomaly Scan - 20/40 Dating Scan - 11-13/40 Rhesus Immunisation - 28+34/40 Screening Oral Glucose tolerance test for @risk mom - 24-28/40 Onset of Gestational HTN - 24/40 Quadruple screening test for downs - 14-20/40 Combined screening test for Downs - 10-13/40
When is gestational diabetes most likely to start and what happens postpartum(PP)
2nd trimester (no micro/macrovasc comps) higher risk for more GD or DM2 in the future, though may revert to normal PP. Give lifestyle advice.
Name Diabetes Risks (SMASH)
Shoulder dystocia Macrosomia Amniotic fluid excess Stillbirth HTN and hypoglycaemia Miscarriage and cong. malformations (DM) Polyhydramnios
Effects of pregnancy in pre-existing diabetes
Inc insulin requirement Acc. of retinopathy Deteriorating renal function Maternal hypoglycemia early on
Management of preexisting diabetes
Refer to Diabetes clinic, pre-conception counseling, monitor vasc comps, early viability and detailed anomaly scan. Special growth scans.
Screening eligibility for Gest. Diabetes
Obesity Previous GD Previous large baby Fhx Previous unexplained stillbirth Polyhydramnios and large for dates
Shoulder dystocia maneuvers
McRoberts (flex and externally rotate hips, Suprapubic pressure, episiotomy
In pregnancy, what BP would cause you concern?
160/90
Main causes of HTN and what percentage of pregancies?
Pre-eclampsia, pre-existing, gestational 10%
Define Pre-eclampsia
HTN and proteinuria in 2nd trimester
Complications of pre-eclampsia?
still birth, premature delivery, fetal growth restriction Placental abruption, eclampsia, HELLP, DIC, Death
Explain pre-existing HTN
Uncommon; 1/3 may turn into pre-eclampsia. Dx before 20/40 or before conception. Careful monitoring required
Gestational HTN
>20/40; BP> or =140/90; usually resolves 2 weeks PP
Pre-eclampsia What is it, when, how does it progress?
Disease of placenta, onset after 20 w. Resolves after delivery. HTN +/>140/90 first, then proteinuria >300 and variable oedema (hands, face, ankles…)
Normal placentation
Early blastocyst attachment -> trophoblast invades myometrium (lacunae) -> chorionic villi surrounded by maternal blood -> 2nd trophoblast invasian causes despiraling of maternal spiral arteries - high blood flow
Pre eclampsia Placentation
Failure of 2nd trophoblast invasion -> no spiral artery remodeling - high R, low flow placenta -> vasospasm and endothelial dysfunction
Risk Factors for pre-E
precious Pre-E - 5% recurrence 1st or twin pregn. Anti-PL syndrome Chronic HTN, renal dx Obesitym smoking Fhx
Treatment of pre-E and drugs used
treat BP <160/90 (prevent stroke) until 6w PP Delivery of placenta is key Labetalol NOT IN asthma, small for dates Methyldopa NOT IN depression Nifedipine Caution in CV probs NOT ACE-i - cong malformations or DIURETICS - red. maternal plasma volume
4 RED FLAGS pre-e -Symptoms -Signs
- Headache - visual disturbance - epigastric or RUQ pain - SOB - periorbital oedema - hyperreflexia - clonus - fits
What are the “Pre-eclampsia bloods”?
FBC - dec platelets Low Hb - Hemolysis with HELLP U&E raised Urate raised AST raised
What is monitored in Pre-e?
Sx, BP, urine; fetus; umbilical artery flow, bloods
Emergency mx - Pre-e
ABC - oxygen, intubation Turn pt onto side Control fits with IV magnesium sulfate Control htn with IV labetalol/hydralazine
HELLP - what is it and what are the complications
Haemolysis, Elevated Liver enzymes, Low platelets. Microangiopathi hemolysis. Risks are DIC, renal failure, low platelets
Pre-e timing of delivery; what about steroids, CS?
34+w if possible; use maternal steroids up to 34w. Delaying delivery by 24hrs to give steroids red. fetal mortality by 50% CS: high BP, renal/hep probs, fetal distress
Eclampsia: what is it and how do you manage it?
Tonic-clonic seizures - before during or after delivery. obstetric emergency; O2, Mg Sulfate, IV hydralazine/labetalol; monitor fluids.
What does dichorionic mean?
Two placentas
What are the complications of twin pregnancies
Prematurity IUGR TTS Emergency Cs HTN, anaemia, Polyhydramnios, acute fatty liver, placnta praevia Increased risk of abruption, Cord prolapse, Increased perinatal mortality
Define Zygosity, chorionicity and Amnion
Zygosity = egg # Chorionicity = placenta # Amnion = inner layer of fetal membranes
What about dizygous twins
Always dichorionic; no anastomoses; show thick dividing membranes and Lambda sign (triangle between sacs)
Monozygotic twins
dichorionic - approx 1 in 3 monochorionic/diamniotic (4-8d) - 70%; monoamniotic (8-13 days) - 30% and highest mortality Conjoined twins in case of 2 week-division Thin membrane and T sign!
Twin preg. antenatal care
early dx, frequent visits, high folic acid and iron, recognize and mx preterm labour. watch for HTN/pre-E
Explain the Twin-twin transfusion syndrome and side effects for both twins
In monochorionic twins which share intraplacental anastomoses (circulation) Umbilical artery of donor twin feeds the vein of the recipient Develops in 20% Varies in severity and may need lasering of vessels. Donor twin: Anaemic, growth restriction, Hypotension, Oligohydramnios Recipient twin: Polycythemic, Hypertensive, cardiac hyertrophy, Oedema, Polyhydramnios.
Definition of SGA (Small for gestational age)
A newborn with the birth weight <10th percentile for gestational age. For fetus its the estimated weight.
Aetiology of SGA - types (SWAN)
Starved small (IUGR) - asymmetric (abdomen more) Wrong small - dating wrong Abnormal small - chomosomal, structural, infection, genetic Normal small - genetic, constitutional
Causes of IUGR
Multiple pregnancies, multiple fibroids, uterine anomaly, Maternal diabetes, Pre-E, Drugs and Alc, Placental dysfunction
Define IUGR
A fetus that has failed to achieve its genetic growth potential Perinatal mortality rate increased by up to 10 fold
Early complications vs later ones?
Early: Hypoglycemia, Plycythemia, NEC, Prematurity complications (neonatal death, RDS, intaventricular hemorrhage) Late - Cognitive delay, cerebral palsy - Chronic adult diseases ie metabolic syndromes
How do you identify high risk pregnancies for IUGR
(SWAN) SHIT Smoking HTN IUGR previously Twins USS Dating, Low threshold for growth scans. Risk reduction and optimise medical conditions, screen for pre-E, serial growth scans
Management of IUGR
Give steroids between 24-34 weeks to reduce risk of NEC, RDS, IVH. Induction or CS; deliver from 34/40 onwards.
What’s the percentage of pre-term (PT) labour in the UK? What are its risks?
7-10% Cerebral palsy, most common risk factor is prematurity Mortality and morbidity inc the earlier delivered.
Risk factors causing PT labour
Multi-fetal pregnancy Previous hx or miscarriage More common after cervical surgery
Causes of PT labour
Stretch of myometrium and fetal membranes Weak cervix Ascending infection
Screening to prevent preterm labour
Cervical length measurement, for those with previous PT delivery or late misc.