Antenatal Care Flashcards
SFH = symphysis fundal height
- it should equal what?
- a difference of +/- __cm is considered significant in suggesting the baby is a bit small/large for gestational age, and would warrant further ix
- should equal gestational age in weeks
- >2cm is significant
Define Pre-eclampsia:
high BP >140/90mmHg with significant proteinuria
must have been normotensive <20weeks
Name 3 RFs for Pre-eclampsia (PET):
- PET in previous pregnancies
- fam hx of PET
- Pre-existing HT
- Age
- Pre-existing renal disease
- DM esp. if on insulin/systemic disease
- multiple pregnancy
- nulliparous
What bloods are done at the booking visit looking at the actual blood?
- FBC (to correct anaemia if present)
- Haemoglobinopathy screen for thalassaemia, sickle cell etc
- Blood group (if rhesus negative may need anti-D, can check babys type via NIPT seeing cf DNA, if baby also negative no need for anti D)
What bloods are done at the booking visit looking at infection which could be vertically transmitted to baby? Name 2
- Syphilis (rx w benzylpenicillin)
- HIV (treat w ARVs to undetectable)
- Hepatitis B (may need immunoglobulins/vaccine when born)
Dating scan to establish EDD and current gestational age is done at what week?
-Dating scan is done at 11-13 weeks (crown rump length CRL is used to date gestational age)
The anomaly scan occurs at what gestational age?
20weeks
The flow through the uterine arteries are measured, why? what does it reflect? When would you be worried? If resistance is high, what medication is started to improve outcomes?
Reflects perfusion to placenta and uterus
If high resistance of flow, indicates possible risk of perfusion and risk of pre-eclampsia and child being small
-Aspirin if given to stabilise the endothelium of vessels so delays the onset of PET
-
PET = endothelium becomes dysfunctional due to cytokines released by placeta. It lines all organs so pre-eclampsia bloods try to look for any organ dysfunction.
Therefore suggest 4 bloods you would do (&why)
- renal profile (look for creatinine)
- liver profile (look for transaminitis)
- haematological: FBC, look for platelet count, anaemia from haemolysis)
- coagulation profile (DIC risk)
What is the basics of physiological changes of BP in pregnancy?
- vasodilation causes BP to decrease from 6weeks on
- 20-24 weeks is the lowest BP
- as progresses towards term, BP will increase (by increased SV and HR) steadily but remains in normal range
BP that is high and presents <20wks gestation is called?
- if the BP is high and there is significant proteinuria <20weeks gestation this suggests?
- if normotensive before 20 weeks then develops HT this is called?
- BP high at booking, is pre-existing HT
- with protenuria is pre-existing HT secondary to renal disease
- after 20weeks, HT is called PIH (Pregnancy Induced HT)
NB: PET doesn’t only affect the mother systemically, what effects can there be on the foetus?
-the uteroplacental unit can -> foetal growth restriction, abnormal umbilical artery Doppler waveform analysis or still birth
Pre-eclampsia is the the leading cause of iatrogenic _____
why? (relates to treatment..)
Prematurity - as only rx is to deliver the placenta (offending organ) delivery is only way to avoid eclampsia
Normal = trophoblasts invade maternal vessels in decidua and change narrow spiral arteries into wide bore low-resistance vessels, why is this beneficial?
- good for gas exchange
- can deliver large amounts of maternal blood
- better nutrient and o2 delivery to foetus (slower flow so more time for exchange)
What is the pathophys of PET on the uteroplacental circulation?
-deficient trophoblast invasion
-spiral arteries not remodelled
-high resistance placental bed
-poorly perfused hypoxic placenta
-deficient nutrient and o2 delivery
-release of inflammatory cytokines (IL, TNF…)
-
What is the pathophys of PET on the maternal endothelium because of the inflammatory cytokines released?
- increased vascular reactivity and vasospasm
- increased capillary permeability and reduced intravascular volume
- risk of peripheral and pulmonary oedema (fluid restriction may be necessary to avoid this complication)
State 3 aspects of the management of pre-eclampsia?
(NB: ‘cure’ for PET is delivery
- treat BP aiming for 130/80mmhg
- monitor sx, signs, bloods
- growth scan for baby checking blood flow
- aim to delivery at 37 weeks unless compromise before this
- if eclampsia: stabilise BP, treat w magnesium sulphate (to prevent seizures) and DELIVER
State a long-term risk for the mothers health from PET after delivery
- 1/3rd develop chronic HT in the year after pregnancy
- ~50% will have cardiovascular disease later in life
- so need to see GP annually for a BP check
Why are women in a pro-thrombotic state in pregnancy physiologically?
- extra volume so that if they bleed at delivery they have enough reserve
- to prevent haemorrhage at delivery
- clotting factors increase, fibrinolytics decrease
Name 5 RFs that increase the pro-thrombotic state, and risk of VTE on top of the physiological changes in pregnancy:
- inherited thrombophilia’s
- obese
- smoking
- older age
- > parity 3, multiple pregnancy
- ovarian hyperstimulation syndrome (OHSS) -> intravasc deplete, dehydrated -> clots
- sepsis
- haemorrhage
- C-section surgery (immobility)
Where are VTEs most commonly in pregnancy and why?
- left-sided (as uterus usually compresses vessels here more)
- ilio-femoral
What is the rx for VTE in pregnancy?
NB: -warfarin = teratogenic so only used for post-natal complications
- LMWH
- IV heparin, if renal problems or near delivery (easier to reverse if necessary)
Name 2 complications of DVT
- PE
- chronic vascular insufficiency
- post-thrombotic syndrome
Diagnosis of PE in pregnancy?
- look at legs, do a leg doppler: if confirmed can treat
- if negative, need to do CTPA or VQ scan
compare and contrast VQ scan and CTPA or no scan for PE dx in pregnancy:
- CTPA: ionising radiation, increases risk of breast cancer 1 in 1000, contrast has 1: 13,000 risk of causing childhood leukaemia to child
- risk of clot going unnoticed can -> death
- VQ scan may not pick up clot but is no ionising radiation and no contrast
- if treated without imaging will affect risk assessments in future and can effect insurance etc
What is an amniotic fluid embolism?
NB: if suspected, must initiate a major obstetric haemorrhage protocol to prophylactically get blood products, why?
- amniotic fluid gets into maternal circulation
- sudden onset chest pain, SOB, collapse, cyanosis
- then women will come round after resuscitation, they start bleeding profusely (DIC)
- because the amniotic embolism uses up all the coagulation factors
What is the principle of managing an amniotic fluid embolism?
- supportive rx: O2, intubate
- correct coagulopathy
- initiate a major obstetric haemorrhage protocol
Give 2 causes of antepartum haemorrhage, what are they briefly?
- Placenta praevia: placenta covering the cervix
- Placental Abruption: placenta coming away from uterine wall prematurely
- Vasa Praevia: foetal blood vessels run through the membranes that cross over the cervix, when membranes break, so will vessels and baby’s blood supply will bleed out
Placenta praevia (1 in 200 pregnancies), placenta covering cervix
- what is the biggest RF?
- when/how is it usually diagnosed?
- how must they deliver?
- previous C-sections, the more history, the worse risk
- usually dx at 20week scan seen as a low-lying placenta
- need to deliver by C-section
Placenta praevia sx/signs that may make you suspect it?
- high presenting part
- abnormal lie
- PAINLESS per vaginal bleeding
- soft-non-tender uterus
PLACENTA
>20mm from interal os = normal
<20mm from internal os = __-____
covering internal os = ____ ____
- <20mm = low-lying
- covering = placenta praevia
Name 3 associated risks of placenta praevia:
- maternal blood loss, antepartum haemorrhage
- malpresentation
- pre-term birth
- abnormally invasive placenta (‘placenta accreta) w previous c-section, placenta can invade the scar of the previous c-section
Placenta accreta is classified depending on how invasive the placenta is:
- <50% invaded into myometrium called a____
- > 50% invaded called i____
- invaded all the way through to serosa p____
- accreta
- increta
- percreta
Management principles of placenta praevia:
any foetal/maternal compromise -> immediate delivery by cs
- NO vaginal exams (finger will go into placenta)
- admit, IV access, wide bore cannula, cross match, check Rh group
- USS placental localisation
- consider steroids, to help lung maturation
- let neonatal unit know (poss expectation of pre-term infant)
- if well, elective CS at 37weeks
Vasa Praevia, when would you deliver, why?
- Deliver by c-section
- before cervical dilatation
- aim 35, 36 weeks (not 37 when woman is more likely to go into labour)
What is placental abruption?
NB: -associated w: high parity, smoking, poor nutrition, previous abruption(20% risk), PET, trauma, external cephalic version = manually moving baby out of breech position
Bleeding from behind a normally situated placenta
-bleeding can be revealed, concealed or mixed
How does placental abruption present?
Basics of management?
- +/- bleeding, PAINFUL APH (antepartum haemorrhage)
- woody hard uterus
- manage: IV access, cross match blood, ABCDE approach
- if woman is unstable, you must not deliver baby
- if woman stable but foetal compromise-> emergency c-s in 20min (category 1)
Suggest 3 complications of placental abruption:
- maternal and foetal morbidity and mortality
- AKI
- hypovolaemic shock
- DIC
- post partum haemorrhage
Suggest 2 non-pregnancy related causes of APH, which you could do a speculum exam to examine for?
- cervical cancer
- cervical polyp
- cervical erosion
Sickle Cell and Thalassaemia Antenatal Screening
- based on ethnic origin women are screened by blood test
- between pre-conception, to 10 weeks
- if +, what are the next ix
- offer partner testing
- if +, offer prenatal dx with CVS or amniocentesis
- if foetus affected, offer: termination or early specialist care
Chromosomal Abnormalities Screening
- who gets scan
- when?
- what/how?
- all pregnant women offered
- between 11-14 weeks
- combined test US: nuchal translucency, bHCG, pappa-A
In general trisomy 21 have ____ b–HCG than normal foetus’s,
whereas ___ papp-A is associated with Trisomy 21
Trisomy 21:
- higher bHCG
- low Pappa-A
In trisomy 21, h-HCG is higher, papp-A is low
What about in Trisomy 18 (Edward’s) and trisomy 13 (Patau)?
-trisomy 18 & 13: lower B-HCG and lower Pappa-A
Fetal Anomaly Scan
- when?
- how?
- -18-22weeks
- US : structured review of organ system
Risk of amniocentesis is not 1%, it is at most ~___%
0.3%
