OBS & GYNAE WK 4 Flashcards
Placenta-oxygen transport
passive diffusion
oxygen and nutrients pass thru placenta from mum -> foetus
CO2 and waste - foetus to mum
the supply of the foetus with oxygen is facilitated by what 3 factors??
fetal Hb - increase in carrying capacity of O2
higher Hb concentration in foetal blood
Bohr effect - foetal Hb can carry more O2 in PCO2
human placental lactose - when is it produced and what is it involved in ??
from wk 5
decreases insulin sensitivity in mothers
Importance of HCG
useful to monitor changes in levels eg. ectopic pregnancy (static), failing pregnancy (falling)
side effect = nausea and vomiting
levels fall from 12-14 wks
cardiovascular changes in pregnancy
increase in CO
increase in HR
BP DROPS DURING 2ND TRIMESTER (rises in 3rd trimester)
The _________ acts as a physiological
arteriovenous shunt
placenta
CRH pathway
CRH-> ACTH -> aldosterone / cortisol
ECG changes in pregnancy
sinus tachycardia
INVERTED T WAVES
Q wave
haematological changes in pregnancy
PV increases
RBC INCREASES
Hb is decreased by dilution
NEED MORE IRON
WHO definition of anaemia in pregnancy
1st tri = <110g/L
2nd and 3rd = <105g/L
postnatal = <100g/L
normally outside of pregnancy, normal level = 120-160g/L
Mx of major haemorrhage - trauma vs obstetrics (postpartum haemorrhage)
trauma = tranexamic acid
transfusion 1:1 RBC:FFP
obstetrics = tranexamic acid
transfusion 4 X RBC
resp changes in pregnancy
lung function changes occur due to progesterone increases and enlarging uterus interfering w lung function
O2 consumption increases
resp rate increases
TV increases
urinary system in pregnancy
increased urinary frequency, increased risk of urine infection, urinary incontinence, retention
postural changes affect renal function
supine position and lateral position - increase in renal perfusion??
_______ _____ contractions increase toward the end of pregnancy
cervical stretching causes ________ release
Braxton hicks - false labour
cervical stretching -> oxytocin release
3 stages of labour
1 - cervical dilatation (8-24hrs)
2 - passing of fetus thru birth canal (few mins - 120mins)
3 - placenta expulsion
what 2 hormones inhibit milk production
what stimulates milk production, and what is responsible for the release of milk??
estrogen and progesterone
prolactin - milk production
oxytocin
how to estimate gestational age - what’s most reliable
crown to rump length - head to butt
12 + 6 wks
head shouldn’t be tucked into chin
can also do head width circumference but this is less effective after 13 wks
FASP
foetal anomaly screening programme - around 20 wks??
can’t pick up all of them
eg. anencephaly, cleft lip, open spina bifida
placenta praevia
placenta is low lying in uterus and covers all or part of cervix
nuchal thickness - Trisomy Risk Assessment
First trimester
measure of skin thickness behind foetal neck using ultrasound
NIPT
aka
Cell free fetal DNA (cffDNA)
non-invasive prenatal testing
- detecting fatal DNA fragment in sample of blood taken from mum
- more specific and accurate
- expensive
The improved accuracy is important as cffDNA itself does not carry any risk of miscarriage, won’t harm the baby
diagnostic tests
amniocentesis
performed after 15 wks
chorionic villus sampling
after 12 wks
sticking needle into abdomen
why is red cell antibodies important ??
may cause fatal anaemia
anti-d injections given- at 28 wks
for blood transfusions
fetal growth - serial measurement of ____ is recommended at each antenatal appointment from 24 wks of pregnancy, as this improves prediction of a SGA neonate
SFH - SYMPHYSIS FUNDAL HEIGHT
small for gestational age
pre-eclampsia
what med is taken 12 - 36 wks ?
CLASSIC TRIAD??
hypertension in pregnancy, can affect every system
take aspirin 12weeks until 36 weeks
HYPERTENSION, PROTEINURIA, OEDEMA
definition of hypertension
140/90 mmHg on 2 occasions, 4 hrs apart
OR
160/110mmHg once
what meds to give for hypertension for women during pregnancy ??
what meds would you stop ??
labetalol (contraindicated in asthma)
Methyldopa (contraindicated in depression)
nifedipine
STOP ACEi/ARB and thiazides
gestational hypertension
2nd half of pregnancy
no systemic features or proteinuria compared to pre-eclampsia
continue antihypertensive - review after 2 wks
who are at high risk of PRE-ECLAMPSIA
Women at high risk are those with any of the following:
-hypertensive disease during a previous pregnancy
-chronic kidney disease
-autoimmune disease such as systemic lupus erythematosis or antiphospholipid syndrome
-type 1 or type 2 diabetes
-chronic hypertension.