81. Pregnancy Flashcards
Gravida (G)
is the total number of pregnancies a woman has had
Primigravida
refers to a patient that is pregnant for the first time
Multigravida
refers to a patient that is pregnant for at least the second time
Para (P)
refers to the number of times the woman has given birth after 24 weeks
Nulliparous (“nullip”)
refers to a patient that has never given birth after 24 weeks gestation
Primiparous
technically refers to a patient that has given birth after 24 weeks gestation once before (see below)
The term primiparous, or “primip” is a bit confusing. Technically, it refers to a woman that has given birth once before. However, it is often used on the labour ward to refer to a woman that is due to give birth for the first time (and has never given birth before). You may hear patients referred to on the labour ward as a “primip” when they have never given birth before.
G and P currently pregnant, 3 children and 1 miscarriage previously
G5P3+1
Currently pregnant, previous still birth
G2P1
what weeks are each of the trimesters
First Trimester (0 to 13 Weeks)
Second Trimester (14 to 26 Weeks)
Third Trimester (27 to 40 Weeks)
Physiological changes renal - pregnancy
Increased perfusion to kidneys (up 30%) → increased GFR (up 30-60%)
Urine : increased protein, increased urea, increased creatinine, trace glucose
Serum: decreased urea, decreased creatinine, reduced albumin
If trace glucose, may offer OGTT at 24 weeks
Physiological changes respiratory - pregnancy
Increased oxygen demands = increased minute ventilation mainly by:
- increased tital volume
Increased ventilation –> reduced CO2 in blood stream –> compensatory fall in bicarbonate (mild fully compensated respiratory alkalosis)
- subjective feeling of breathlessness without hypoxia is common
Physiological changes hematology - pregnancy
RBC
Increased RBC production in pregnancy
Plasma volume increases > red blood cell volume, leading to a lower concentration of red blood cells.
Lower Hb
Lower platelets
Requirements
increased requirements: higher iron, folate and B12 requirements. Also increased calcium req but body absorbs better too so may be unchanged
Clotting
Clotting factors such as fibrinogen and factor VII, VIII and X increase in pregnancy, making women hyper-coagulable (ready for delivery). This increases the risk of venous thromboembolism (blood clots developing in the veins). Pregnant women are more likely to develop deep vein thrombosis and pulmonary embolism.
Placenta
High ALP (up to 4 times higher)
Physiological changes skin and hair - pregnancy
skin:
- Increased skin pigmentation due to increased melanocyte stimulating hormone, with linea nigra and melasma
- Striae gravidarum (stretch marks on the expanding abdomen)
- General itchiness (pruritus) can be normal, but can indicate obstetric cholestasis
Increased estrogen:
- Spider naevi (related to increased estrogen)
- Palmar erythema
hair:
- Postpartum hair loss is normal, and usually improves within six months.
Physiological cardiovascular changes pregnancy
Increased blood volume –> Increased cardiac output (larger stroke volume + higher heart rate)
CO= SV x HR
- Higher heart rate (10-20bpm)
- Ejection systolic murmur
- Third heart sound
Decreased pulmonary vascular resistance and systemic vascular resistance
- Decreased diastolic blood pressure in early and middle pregnancy, returning to normal by term (blood being diverted to placenta)
Peripheral oedema due to:
- increased aldosterone –> fluid retention
- reduced venous return due to pressure of uterus on inferior vena cava (worse if supine) - best position is left lateral
Physiological changes pregnancy - endocrine
- Ant pituitary ^ACTH ^prolactin ^melanocyte stimulating hormone
- ^ACTH –> ^steroid hormones, cortisol and aldosterone = improvement in autoimmune, susceptible to diabetes and infections
- ^Prolactin –> decreased FHS and LH
- ^melanocyte stimulating hormone –> increased pigmentation of skin –> linea nigra, melasma
- TSH nromal, raised t3 and t4
- HCG rise, double every 48 hours until platau around 8-12 weeks then start to fall
- Progesterone rises throughout pregnancy –> prevent contractions, suppress immune response to fetal antigens, produced by corpus luteum until 10 weeks, then placenta
- oestrogen rises throughout pregnancy, produced by placenta
Antenatal timeline
First visit is from 8, check everything with mum is great, urine, bloods and rhesus state, give advice and educate
from 11 to 13 is the best time to do a downs screen while your at it check the dates
at 16 or 10 plus 6 do BP and multistix
second scan is at twenty to check the fingers and toes to make sure there’s plenty
one again at 28, urine blood and rhesus state
anti D if appropriate
when the week is 34 plan for birth, what a chore
check the lie at 36, if breech offer a quick-fix
last visit at 38, all thats left to do wait
what is part of the booking appointment? when is the booking appointment?
From week 8
4 bloods:
FBC
Blood group
Rhesus (rhesus D status and antibodies)
Thalassemia (and sickle cell if high risk)
3 Viruses:
HIV
Syphillis
Hep B
2 urine:
Dipstick
MSU
1 physical exam:
BP
BMI
Screening for Down’s syndrome may be initiated depending on the gestational age. Bloods required for the combined test are taken from 11 weeks onwards.
why is rhesus status important? what does it mean?
The rhesus D antigen is found on RBC.
If someone who is rhesus negative, comes into contact with the rhesus antigen - it sees this as foreign and creates antibodies.
It is important to pick up rhesus-D negative mothers as they may have rhesus positive babies
If the baby’s blood comes into contact with the mothers blood then the mother will produce antibodies against the babies blood (sensitisation)
In future pregnancies, the mothers immune system may initiate a full scale attack and destroy the babies RBC.
Once sensitisation has occurred, there is nothing that can be done. therefore prophylaxis is important to prevent sensitisation
How does anti-D work?
The anti-D medication works by attaching itself to the rhesus-D antigens on the fetal red blood cells in the mothers circulation, causing them to be destroyed. This prevents the mother’s immune system recognising the antigen and creating it’s own antibodies to the antigen. It acts as a prevention for the mother becoming sensitised to the rhesus-D antigen.
When is anti-D given?
Anti-D injections are given routinely on two occasions:
- 28 weeks gestation
- Birth (if the baby’s blood group is found to be rhesus-positive)
Anti-D injections should also be given at any time where sensitisation may occur
Anti-D is given within 72 hours of a sensitisation event. If a sensitisation test occurs after 20 weeks gestation, the Kleinhauer test is performed to see how much fetal blood has passed into the mother’s blood, to determine whether further doses of anti-D are required.
In what situations should an anti-D be given within 72 hours
delivery of a Rh +ve infant, whether live or stillborn
any termination of pregnancy
miscarriage if gestation is > 12 weeks
ectopic pregnancy if managed surgically
external cephalic version
antepartum haemorrhage
amniocentesis, chorionic villus sampling, fetal blood sampling
abdominal trauma
Tests for rhesus sensitisation ?
all babies born to Rh -ve mother should have cord blood taken at delivery for FBC, blood group & direct Coombs test
Coombs test: direct antiglobulin, will demonstrate antibodies on RBCs of baby
Kleihauer test: add acid to maternal blood, fetal cells are resistant (do after a sensitisation event to see if further foses of anti-d are required)
How will an affected fetus present - rhesus sensitisation? pathophysiology? tretament?
jaundice –> kerinicterus, anaemia, hepatosplenomegaly:
anaemia is caused by the destruction of the RBC by the mothers antibodies, jaundice occurs as there is lots of bilirubin from the breakdown of RBC. The spleen is enlarged as it is processing a lrge number of RBC. the liver is large as it is trying to make much more RBC than normal.
oedema and hydrops fetalis:
liver is under strain from making more RBC that other functions suffer such as albumin production. this leads to leakage of fluid into tissues and body cavities, termed hydrops fetalis.
heart failure:
liver is under strain so portal hypertension devlops which strains the heart and ciruclatory system. Also, the severe anemia taxes the heart to compensate by increasing output in an effort to deliver oxygen to the tissues and results in a condition called high output cardiac failure.
treatment: transfusions, UV phototherapy
why does rhesus only cause outcomes in subsequent pregnancies and not the first?
IgM antibodies do not cross the placental barrier, which is why no effects to the fetus are seen in first pregnancies for Rh-D mediated disease.
However, in subsequent pregnancies with Rh+ fetuses, the IgG memory B cells mount an immune response when re-exposed, and these IgG anti-Rh(D) antibodies do cross the placenta and enter fetal circulation.
Management of neonates born to mothers with Hep B
Give at birth:
Hepatitis B vaccine
Hepatitis B immunoglobulin infusion
Infants are given an additional hepatitis B vaccine at 1 and 12 months of age.
They will also receive the hepatitis B vaccine as part of the normal vaccine given to all infants aged 8, 16 weeks, 12 mo
They are tested for the HBsAg at 1 year to see if they have contracted hepatitis B.
Breastfeeding and Hep B
Safe to breastfeed provided their babies are properly vaccinated
Hep B type of virus and spread
DNA virus. It is transmitted by direct contact with blood or bodily fluids.
Testing for Hep C
Hepatitis C antibody is the screening test
Hepatitis C RNA testing is used to confirm the diagnosis of hepatitis C, calculate viral load and identify the genotype
Management babies born to mothers with hep C
tested at 18 months of age using the hepatitis C antibody test
can breastfeed
what do UTIs in pregnancy increase the risk of?
pre-term birth
testing for UTIs in pregancy
MSU for sensitivities and cultures routinely (at booking and at appointments) - treat asymptomatic bacteraemia during pregnancy
MSU and dip when symptomatic
folic acid dosage pregnancy
400mcg per day from prior to getting pregnant to the 12th week of pregnancy
Women with folate deficiency/epileptic drugs/pre-existing diabetes/BMI>30/NTD or FH of NTD/coeliac/thalassemia are started on folic acid 5mg daily until 12th week of pregnancy
either partner has a NTD, they have had a previous pregnancy affected by a NTD, or they have a family history of a NTD
the woman is taking antiepileptic drugs or has coeliac disease, diabetes, or thalassaemia trait.
the woman is obese (defined as a body mass index [BMI] of 30 kg/m2 or more).
