Antenatal Care


History taking



Dates
Last menstrual period (LMP); is cycle regular? use of OCP (may delay ovulation)
Expected Delivery Date (EDD) ie Calculate Predicted Birth/Term Date:

EDD is calculated via:
LMP – 3 months + 7 days OR Use dial ie conception (14 days post start of cycle/mid-way of period) + 38 weeks
OR LMP + 40 weeks

Current pregnancy HOPC (x8)
  • Fatigue A
  • Insomnia B
    obg_hx.jpg
    obg_hx.jpg
  • Headaches B
  • Reflux C
  • NV C
  • Constipation C
  • B/S bleeding or spotting D
  • LAP lower abdominal pain D
Four cardinal symptoms of pre-eclampsia: Headaches, oedema, visual changes and upper abdominal pain (HOVA)

Past obstetrics Hx (GxPx; past deliveries: vaginal/caesarean, normal/breech, spont/ind.)
Past medical Hx (past gynae Hx, medications- HT, renal disease- increase RF x3 for pre-eclampsia)
autoimmune (anti-phospholipase syndrome), DVT, ACA (anti-cardia antibodies e.g. MS, DM), PCOS (insulin resistance; 1/4 DM)
Family history of HT, pre-eclampsia, growth restrictions, DM, multiple pregnancies, genetic/congenital problems)
Habits e.g. alcohol (growth problems), cigarettes (esp later trimesters; RUGR- less than 5th percentile), drugs (cocaine the worst for baby; causes seizures, fetus vasospasm/heart changes; heroine- baby withdrawal symptoms ie use methadone), rings (labia etc RF for Hep B, C- test), allergies
Social Hx- Planned and wanted? (ie happy pregnant? Contraceptives and planned?)
Employment, leave, finance, support,
postnatal depression, psychosis



Examination


General maternal survey including vitals, lungs, thyroid, oedema, BP
Examination of the fetus
Fetal height, fetal heart (Doppler; N110-160 (CTG, AFI later on;~10 visits prior birth)

The examinations below may be included as relevant:
  • Pelvic examination (bimanual palpation as uterus gets softer)
May defer this exam however until after birth
  • Breast exam (breastfeeding advice, check for pathologies)


Investigations


Essential Tests
  • Screen
  • Down Screen
  • 19 week U/S
  • GBS vaginal swab at 36 weeks
(optional: growth US at 32 weeks; CTG from 36 weeks)

Tests in order:
  • FBE
  • Blood group and antibody screen (O+ most common; Rh-ve 10%- give anti-D to prevent erythroblastosis; stillbirth)
  • Serology x 4: HIV, HepB and C, Rubella, Syphyllis
[+] Urine (protein and glucose; MSU for E-coli)
  • U/S: picks up pregnancy best at 9-12 weeks (where there is constant growth;
in the first 10 weeks, baby coubles in length every week)
CRL

  • Screening
Amniocentesis at 16 weeks (0.5% risk) result in 18days/CVS at 13 weeks (1% risk) result in 10 days
FISH test at patient's own cost for faster reassurance; low false negative rate; may have false positives
U/S at 19wks (anatomical- structre, soft signs; placental (if low lying), multiple pregnancies, ovaries, fibroids)
CNT (combined nuchal translucency- risk for trisomy 21)

Management



Vaginal Bleeding
Aetiology is:
1 in 3: bleeding in 1st trimester
1 in 6: threatened abortion (home rest)
1 in 6: fetus NOT viable on trans-vaginal U/S (evacuate uterus 85% successful; mizoprostol or curretage)

Nausea
Cause is often bHCG, later oestrogen
Treatment via encouragement of 'grazing' on dry bland carbs e.g. biscuits; small amount multiple times.
Test ketones in urine (Rx saline 2L)

Folic acid and Vitamin D!!

Vaccinations
whooping cough (aka pertusis vaccine) as part of BOOSTRIX- with diphtheria and tetanus
for mother asap following labour, for child at 6 months
everyone regularly in contact with baby should be vaccinated

Referral



Low/high risk
1°/2°/3 °care
Specialty unit referral?
Model of care




Fetus Monitoring


CTG


1. Baseline N110-160bpm
2. Variability N5-25bpm
3. Reactive N15bmp for 15sec; 2 min 20min window
4. Decelerations

Variability is due to autonomic control (parasympathetic via the vagus and sympathetic via arteries) of the SA node
3-4bpm variability is reduced; less than 3 is absent variability
Ddx for decreased variability:
  • hypoxia
  • sleep state (<20min)
  • pharmacological causes: antihypertensives, beta blockers, opioids (includign methadone), MgSO4 (used in pre-eclampsia), anticonvulsives

Reactivity is classified as normal-reactive, non-reassuring OR pathological
low false negatives 1/1000, high false positives 80% ie cannot act on non-reassuring trace
Continue trace/biophysical profile if in doubt about variability
Decelebrations has 4 classifications: early, late, variable OR prolonged
early: fontanelle compression: non-pathological
late: if combined with decreased variability, fetus is suffering from HYPOXIA
variable: in timing, shape, duration, amplitude; sharper gradient than early/late. Reason is CORD COMPRESSION. (usually after ROM as loss of amniotic fluid and loss of cushioning effect)
prolonged: >90 seconds; cord compression of shoulder? >6min is green code (opt for caesarean section)
APGAR
pH <7.25= acidotic baby
N.B. lupus- anti-SSA crosses placenta, targets endothlium of heart in fetus

Maternal Serus Screen



Beta HCG
Alpha Fetoprotein
Oestradiol
Inhibin

Biophysical Profile

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CRL N 6-7 cm
BPD N 2-3cm
HC (head circumference) 8cm
AC (abdo circumference) 6.5cm
FL (femur length) 1.1cm N
.B. 5mg folate for twin pregnancy instead of 0.5mg



FWT
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Proteinuria
Glucosuria

Special tests

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  • GDM has a 40% reucrrence rate in subsequent pregnancies

GCT- glucose challenge test
screening test
1 hr post glucose ingestion

GTT- glucose tolerance test
definitive test if greater than 7.9
2 hrs post glucose ingestion

  • Down Syndrome
combined risks if greater than 1/300 discuss
Do amniocentesis if greater than 1/200


Genetic testing



external image fetus_amniotic_sac.gif
external image fetus_amniotic_sac.gif