OBS - Antenatal Care Flashcards
1
Q
Pregnancy Timeline
Booking Clinic Dating Scan Down Syndrome Screening Anomaly Scan Antenatal Appointments Vaccines
A
- ) Booking Clinic - 8-12wks (preferably <10weeks)
- offer a baseline assessment and plan the pregnancy - ) Dating Scan - between 10 to 14wks (13+6)
- gestational age is calculated from the crown-rump length (CRL), and multiple pregnancies are identified
- down syndrome screening also offered at this stage
3.) Down Syndrome Screening - between 11-14 weeks
- ) Anomaly Scan - between 18 to 21wks (20+6)
- USS to identify any anomalies, e.g. heart conditions - ) Antenatal Appointments - first one is at 16wks
- discuss results and plan future appointments where you monitor the pregnancy and discuss future plans
- weeks 25, 28, 31, 34, 36, 38, 40, 41 and 42
- BP, urinalysis (inc MC+S)
- anti-D for Rh-ve women on weeks 28 and 34
- measure symphysis–fundal height (SFH) from 24wks onwards, fetal presentation assessment from 36 wks - ) Vaccines - two vaccines offered to all women
- whooping cough (pertussis) from 16wks gestation
- flu vaccine when available in autumn or winter
- live vaccines e.g. MMR are avoided in pregnancy
2
Q
Booking Clinic
What is it? Education Booking Bloods Other Measures Risk Assessment
A
- ) What is it? - first appointment to discuss and arrange plans for the pregnancy with a midwife
- ideally occurs before 10 weeks gestation
- get a green book documenting pregnancy progress - ) Education - pregnancy-related topics covered:
- what to expect at different stages of pregnancy, discuss mental health, plans for birth
- lifestyle advice, supplements, screening tests
- antenatal and breastfeeding classes - ) Booking Bloods
- FBC, blood group, red cell alloantibodies, rhesus D status, screening for thalassaemia in all women and sickle cell disease for women at higher risk
- offered infection screening: HIV, hep B, syphilis
- if high risk for hepB, the baby needs the hepB vaccine soon after birth and then at 1-2mth and 6mths
- if hepB +ve, the baby needs 0.5mL hepB IG within 12 hours of birth
- breastfeeding is safe in hep B but not in HIV - ) Other Measures
- EDD: calculated using the Naegele rule (add 7 days to LMP, then add 9 months), assumes 40wk pregnancy
- BMI (weight, height), BP, urine dip
- discuss domestic violence and FGM - ) Risk Assessment - for other conditions and plans are put in place with extra appointments booked:
- GDM (book OGTT), Rh- (book anti-D prophylaxis),
- fetal growth restriction (book extra growth scans)
- VTE (provide prophylactic LMWH if high risk)
- pre-eclampsia (provide aspirin if high risk)
3
Q
Pregnancy Lifestyle Advice
Supplement Advice Alcohol Advice Smoking Advice General Advice Flying Advice
A
- ) Supplement Advice
- take vitamin D supplements (10 mcg or 400 IU daily)
- avoid vitamin A supplements and eating liver or pate
- take folic acid 400mcg in the first trimester (0-12wks)
- may require a higher dose of folic acid (5mg) due to:
- obesity (BMI >30), diabetes, previous hx/FH of neural tube defects, use of AEDs, Coeliac’s disease, thalassaemia trait, HIV positive taking co-trimoxazole
2.) Alcohol Advice - do not drink as it can disrupt fetal development because it can cross the placenta
- complications: SGW, miscarriage, pre-term delivery
- fetal alcohol syndrome: LD, behaviour difficulties, hearing/vision problems, cerebral palsy
- physical features in FAS: microcephaly, thin upper lip,
smooth flat philtrum, short palpebral fissure
- ) Smoking Advice - don’t smoke, ↑ the risk of:
- FGR, miscarriage, preterm labour, stillbirth
- placental abruption, pre-eclampsia, cleft lip or palate
- sudden infant death syndrome (SIDS) - ) General Advice
- avoid undercooked or raw poultry (risk of salmonella)
- avoid unpasteurised dairy or blue cheese (listeriosis)
- continue moderate exercise but avoid contact sports
- place seatbelts above and below bump (not across)
- sex is safe - ) Flying Advice - flying increases the risk of VTE
- generally ok in uncomplicated healthy pregnancies up to 37wks or 32wks in a twin pregnancy
- after 28wks, most airlines need a note from a GP or midwife to state there are no additional risks
4
Q
Down Syndrome Screening
Screening
Combined Test
Quadruple Test
Invasive Tests
Non-Invasive Prenatal Testing
A
- ) Screening - offered to all women to see if they need more invasive tests to establish a definitive diagnosis
- screening tests provide a risk score, if high risk (>1/150), the woman is offered more invasive tests - ) Combined Test - first-line, done between 11-14wks
- tests for Down’s (21) Edwards’ (18) and Pataus’ (13)
- combines US results and maternal blood tests
- also includes age (↑risk in older women) and ethnicity
- US: nuchal translucency, nuchal thickness >6mm (also suggests congenital heart and abdo wall defects)
- maternal blood tests: high beta-HCG, low PAPP-A - ) Quadruple Test - done between 14-20wks
- tests only for Down’s and only uses blood results
- ↑beta-hCG, ↓AFP, ↓serum estriol, ↑inhibin-A - ) Invasive Tests - taking a sample of the fetal cells to perform karyotyping for a definitive answer
- chorionic villus sampling (CVS): US-guided biopsy of the placental tissue, done if testing done early (<15wks), 1% risk of miscarriage
- amniocentesis: US-guided aspiration of amniotic fluid, used in later pregnancy so there is enough fetal cells in the amniotic fluid, 1% risk of miscarriage - ) Non-Invasive Prenatal Testing - a new test to detect abnormalities, involves a simple maternal blood test
- tests for all 3 or just tests for Edwards and Patau’s
- only offered for high-risk patients
- needs at least 4% fetal fraction
- analyses fragments of fetal DNA from the placenta
- not definitive only high chance (>50) or low chance
5
Q
Small For Gestational Age (SGA)
Definitions
Aetiology and Pathophysiology
Major Risk Factors
Minor Risk Factors
A
- ) Definitions
- SGA: infant w/ birth weight <10th centile for its age, becomes severe when birth weight is <3rd centile
- fetal SGA: estimated fetal weight (EFW) or abdominal circumference (AC) <10th centile, severe <3rd centile
- fetal growth restrictions: pathological restriction of genetic growth potential, fetus is often compromised
- low birth weight: birth weight <2.5kg (5.5lbs)
2.) Aetiology and Pathophysiology
- normal: small at all stages, growth follows the centiles
- placenta-mediated GR: initially normal but slows in utero, due to maternal causes of placental insufficiency: HTN, DM, substance abuse, renal/autoimmune disease
- non-placenta-mediated GR: anomalies (chromosomal
or structural), error in metabolism or fetal infection
- ) Major Risk Factors
- age >40, smoker(>11d), cocaine use, vigorous exercise
- hx of SGA baby or stillbirth, maternal/paternal SGA
- maternal disease: HTN, DM w/ vascular disease, renal or autoimmune disease, antiphospholipid syndrome
- heavy bleeding, low PAPP-A (pregnancy-associated plasma protein-A) - ) Minor Risk Factors
- age >35, smoker(1-10/d), BMI <20/>25, low fruit intake
- nulliparity, IVF singleton, previous pre-eclampsia, pregnancy interval <6mths or >60mths
6
Q
Management for SGA
Clinical Features
Investigations
Management
Complications
A
- ) Clinical Features
- constitutionally small: symmetrically small so normal HC (head circumference) to AC ratio
- asymmetrically small (↑HC:AC) may suggest placenta insufficiency as ‘brain-sparing’ occurs (seen in doppler)
- ↓amniotic fluid volume: placental insufficiency can impair kidney function - ) Investigations
- USS biometrics inc EFW and AC are plotted on centile charts: height, weight, ethnicity, parity
- detailed fetal anatomical survey
- uterine artery Doppler (UAD), karyotyping
- infection screening inc congenital cytomegalovirus, toxoplasmosis, syphilis and malaria - ) Management
- prevention of modifiable risk factors
- surveillance: UAD every 2wks or more frequent, CTG, pubic-symphysis height, amniotic fluid volume
- early delivery: different indications dependent on:
- <37w: C-section if absent/reverse end-diastolic flow on doppler, will require antenatal steroids if <36wks
- by 37w: IOL if abnormal UAD or MCA doppler
- at 37w: IOL even with normal UAD - ) Complications - ↑ the risk of stillbirth alongside:
- neonatal: asphyxia, meconium aspiration, hypo/hyper-glycaemia, hypothermia, polycythemia, retinopathy, pulmonary HTN/haemorrhage, necrotising enterocolitis
- long-term: cerebral palsy, T2 DM, obesity, HTN, early puberty, behaviour problems, depression, Alzheimer’s, cancer (breast, ovarian, colon, lung and haematological)
7
Q
Large for Gestational Age (Macrosomia)
Definition Aetiology/Causes Complications/Risks Investigations Management
A
- ) Definition
- macrosomia: infant birth weight is >4kg at birth
- fetal LGA: estimated weight >90th centile - ) Aetiology
- constitutional (normal), male baby, overdue baby
- maternal diabetes, obesity or rapid weight gain
- previous macrosomia - ) Complications/Risks - for the mother and baby
- mother: shoulder dystocia, perineal tears, C-section or instrumental delivery, PPH, uterine rupture
- baby: birth injury (Erb’s palsy, clavicular fracture, fetal distress and hypoxia), neonatal hypoglycaemia, obesity in childhood and later life, T2 DM in adulthood - ) Investigations
- USS: estimate fetal weight, exclude polyhydramnios
- OGTT to test for gestational diabetes - ) Management - most women still have a vaginal delivery, LGA is not enough grounds for IOL
- main risk is shoulder dystocia, ↓risks by having:
- consultant lead, experienced doctor/midwife, an early decision for C-section if required etc
8
Q
RBC Isoimmunisation
Rhesus Blood Groups
Sensitization Phase
Effector Phase
Clinical Features
A
- ) Rhesus Blood Groups - D antigen is most important
- Rh+ = D antigens present, Rh- = D antigens absent
- D antibodies are produced when Rh- mothers are exposed to D antigens during pregnancy - ) Sensitization Phase - pregnancy w/ 1st Rh+ fetus
- Rh antigens from the fetus enter mother’s circulation during delivery/APH/abdo trauma/miscarriage
- mother produces anti-Rh+ antibodies (IgG) - ) Effector Phase - pregnancy w/ 2nd Rh+ fetus
- anti-Rh+ antibodies cross the placenta in T3, damaging the fetal RBCs causing haemolytic disease of the newborn (HDN)
- can also affect the current pregnancy if the sensitisation event occurs early enough - ) Clinical Features
- ↑bilirubin leads to jaundice
- bilirubin can enter the brain to cause kernicterus which can cause permanent neurological damage
9
Q
Management of Isoimmunisation
Anti-D Immunoglobulin
Investigations
Management of Sensitising Events
A
- ) Anti-D Immunoglobulin - antibodies for Rh antigens which is often known as RhoGAM
- binds to Rh antigens in the newborn, so the mother is not sensitised (never exposed to Rh antigens)
- given to Rh-ve women on week 28 and week 34
- also given following a sensitizing event:
- delivery, APH, ectopic pregnancy, fall, abdo trauma
- intrauterine death, miscarriage, abortion (TOP)
- external cephalic version, invasive obstetric testing (e.g amniocentesis or chorionic villus sampling) - ) Investigations
- maternal blood group and antibody screen: finds out ABO and RhD blood groups (indirect Coombs test), detect any antibodies directed against RBC surface antigens (except A or B)
- feto-maternal haemorrhage (FMH) test (Kleihauer): assesses how much fetal blood has entered the maternal circulation, used to determine how much anti-D should be given
- FMH is performed if a baby is RhD+ and mom is RhD- (can be performed from 16wks onwards)
- flow cytometry can be used for a more accurate estimation of the amount of fetal blood in the mother - ) Management of Sensitising Events
- <12w: 250 IU anti-D, within 72hrs of the sensitizing event (ectopic, molar, TOP, heavy uterine bleeding)
- 12-20w: 250 IU anti-D, within 72 hours of any event but no FMH test
- >20w: 500 IU within 72 hours of the event with a FMH test to titrate the dose to the size of the FMH
10
Q
Multiple Pregnancy
Types of Twins
Diagnosis
Complications
Twin-Twin Transfusion Syndrome
A
- ) Types of Twins
- monozygotic: identical twins (from a single zygote)
- dizygotic: non-identical (from two different zygotes)
- monoamniotic (1 amniotic sac), diamniotic (2 sacs)
- monochorionic (1 placenta), dichorionic ( 2 placentas)
- best outcomes are with diamniotic and dichorionic twins because each fetus has its own nutrient supply - ) Diagnosis - usually on the booking/dating US scan
- dichorionic: membrane between twins (lambda sign)
- monochorionic: membrane between twins (T sign)
- monochorionic monoamniotic: no membrane - ) Complications - to the mother and the baby
- mother: HTN, anaemia, polyhydramnios, PPH, pre-term birth, malpresentation, C-section or instrumental
- baby: FGR, miscarriage, prematurity, stillbirth, congenital abnormalities, twin-twin transfusion syndrome, twin anaemia polycythaemia sequence - ) Twin-Twin Transfusion Syndrome - occurs in monochorionic twins as they share a blood supply
- one fetus receives a majority of the blood so they can become fluid overloaded –> polyhydramnios, HF
- one fetus starves –> oligohydramnios, FGR, anaemia
- require referral to a tertiary specialist fetal medicine centre, may need a laser to destroy the connection
- twin anaemia polycythaemia sequence: less acute, one becomes anaemic, other develop polycythemia
11
Q
Management of Multiple Pregnancies
Antenatal Care
Planned Birth
Delivery
A
- ) Antenatal Care
- specialist multiple pregnancy obstetric team should manage women with a multiple pregnancy
- require more FBCs: booking clinic, 20wks, 28wks
- extra USS: 2wkly from 16wks for monochorionic, 4wkly from 20wks for dichorionic twins - ) Planned Birth - early delivery to reduce the risk of fetal death, corticosteroids are given before delivery
- uncomplicated monochorionic monoamniotic twins should be delivered between 32 and 34wks( 33+6)
- uncomplicated monochorionic diamniotic twins should be delivered between 36 and 37wks (36+6)
- uncomplicated dichorionic diamniotic twins should be delivered between 37 and 38 wks (37+6)
- triplets should be delivered before 36wks (35+6) - ) Delivery
- monoamniotic twins require an elective C- section
- diamniotic twins can have a vaginal delivery only if the first baby has a cephalic presentation, otherwise, an elective C-section is required
12
Q
Prolonged Pregnancy
Aetiology Complications Clinical Features Investigations Management
A
- ) Aetiology - unclear cause but risk factors include:
- nulliparity, maternal age >40, high BMI
- previous or family history of prolonged pregnancies - ) Complications - increased risk of stillbirth
- due to the ↑potential for placental insufficiency
- ↓O2 and nutrient transfer depletes fetal glycogen stores, resulting in neonatal hypoglycaemia
- ↑risk of fetal acidaemia and meconium aspiration
- increased need for instrumental or C-section - ) Clinical Features - based on gestational age
- static growth or potentially macrosomia
- oligohydramnios, reduced fetal movements
- signs of meconium or meconium staining
- dry/flaky skin w/ reduced vernix (waxy, a white substance found coating the skin of newborn babies) - ) Investigations
- dating USS scan between 11 to 14wks gestation
- USS to check growth, liquor volume and dopplers are frequently performed to monitor prolonged pregnancy - ) Management
- delivery by 42 wks to reduce the risk of stillbirth
- membrane sweeps: from 40wks in nulliparous and 41wks in parous women
- IOL offered between 41 and 42wks gestation
- emergency C-section in signs of fetal distress
