What are the three phases of the coagulation process?
- Temporary plug - Platelets adhere to damaged vessels
- Fibrin clot - Permanent clot forms
- Fibrinolysis - Break down of the clot as the vessel heals.
What are known risk factors for thrombosis?
Increased plasma concentration of oestrogens or progesterones - ie ovarian hyperstimulation
Pregnancy - increased clotting factors and decreased fibrinolysis.
Childbirth (LSCS, high instrumental, prolonged labour, grand multips)
AMA Obesity Immobility Trauma and surgery Dehydration Haemorrhage Infection/sepsis Smoking Stress Hypertension Thrombophilia Diabetes Family Hx
What is Virchow’s triad?
The three causes of coagulation:
- Endothelial injury - trauma/surgery, previous clots, compression, varicose veins, recreational IV drug use
- Abnormal blood flow - Narrowed blood vessels (preeclampsia); Venous stasis and sluggish blood flow ie dehydration, immobility, sickle cell disease.
- Hypercoagulability - affected by pregnancy, childbirth, infection, inflammation, tissue damage, smoking, inherited conditions, age, pre-existing disease, drugs (ie OCP)
Clomid is the brand name of which drug?
Clomiphene citrate
What is Clomid used for, and what is it’s mechanism of action?
To stimulate ovulation to achieve pregnancy.
Stimulates increased output of pituitary gonadotrophins which stimulate the maturation of the ovarian follicle and subsequent development of the corpus luteum.
What are contraindications for Clomid?
Liver disease
Hormone-dependent tumours or abnormal uterine bleeding
Pregnancy
Ovarian cysts (except PCOS)
How is proteinuria measured?
Historically 24 hour urine collection;
Now - spot protein:creatinine ration is a good estimate.
Risk factors for pre-eclampsia?
First pregnancy, or long gap between pregnancies Renal disease Rhesus incompatability Donor eggs Sickle cell Young or AMA Hx Multiple gestation Diabetes Essential hypertension Molar pregnancy Obesity Clotting disorders.
What is HELLP syndrome?
Haemolysis, elevated liver enzymes, low platelets
What is magnesium sulphate used for?
Prevent further fits in established eclampsia.
What should you consider/monitor to prevent magnesium toxicity?
Magnesium is processed by the kidney’s so if renal function is poor (as it can be with preeclampsia) then there is a risk that it will build up in the blood stream. Dosage should be titrated based on renal function of the individual patient, and a strict fluid balance should be maintained.
What is the antidote to magnesium toxicity?
Calcium glutonate
What are the signs of magnesium toxicity?
Thirst, warmth, flushing. (Early signs)
Respiratory distress, cardiac failure.
What is the definition of hypertension?
> = 140/90
Severe >= 170/110
(As per NSW HEALTH)
What is the first line drug for hypertension in pregnancy?
methlydopa
How does Methyldopa work?
It is an alpha agonist meaning it stimulates the alpha receptors in the brain which then signals vasodilation, lowering blood pressure.
It opposes the actions of adrenaline and noradrenaline and dopamine, inhibiting the sympathetic nervous system.
Contraindications for methyldopa?
Pre-existing or hx of depression
liver or endocrine disease
What type of drug is labetolol?
It is an antihypertensive, and a combined alpha & beta-blocker. Also used for thyrotoxicosis.
Method of action: reduces HR and cardiac output by depressing the renin-angiotensin-aldosterene pathway
Better tolerated than methyldopa, and used in 3rd trimester (prior to 3rd will reduce blood flow to fetus - IUGR, bradycardia, hypoglycaemia and resp depression).
Contraindications for labetolol?
Asthma - they prevent relaxation of smooth muscle of the bronchioles
Glucose control - impair normal response to hypoglycaemia
What is hydralazine used for?
A potent vasodilator used as anti-hypertensive.
Rapid action when used IV in an emergency.
Avoid 1st and 2nd trimesters - sometimes used orally in pregnancy if other drugs not tolerated.
Associated with more adverse effects such as hypotension, LSCS, abruption, low APGAR.
What drugs are used for hypertensive emergencies?
IV labetolol
Oral Nifidipine
IV Hydralazine
Side effects of vasodilatory drugs (Hydralazine, nifidepine, labetolol)
Headache, Flushing nausea nasal congestion tachycardia
Hydralazine - salt and water retention, increased heart rate leading to pulmonary oedema and heart failure.
What are broad-spectrum antibiotics?
Those effective against both gram-positive and gram-negative bacteria.
Which type of antibiotic is more effective against gram-positive, and which for gram-negative bacteria?
Penicillin - gram-positive
Gentamicin - gram-negative
What is Benzylpenicillin used for?
It is effective against gram-positive bacteria only. It is usually used for GBS positive women as prophylaxis.
What antibiotic is commonly prescribed for gram-positive bacteria for patients allergic to pencillin?
Erythromycin.
What are tetracyclines?
Broad-spectrum antibiotics. Not prescribed in pregnancy and lactation.
What drugs are used to treat bacterial vaginosis?
Metronidazole - high doses not recommended in pregnancy. Significant amount passes into breastmilk.
OR
Clindamycin
What drug is used to treat Trichomoniasis?
Metronidazole.
What is used to treat Candidiasis?
Clotrimazole - PV suppository or cream
What drugs can be used to treat chlamydia?
Considered gram-negative:
erythromycin
clindamycin
azithromycin
Which common antibiotics are useful for gram-positive bacteria?
Ben Pen Bacitracin Vancomycin Erythromycin Clindamycin
Which antibiotics are useful for gram-negative bacteria?
Cephalexin
Ampicillin
Gentamicin
Which antibiotics are broad-spectrum?
Tetracycline Doxycycline Augmentin Cephalosporin Bactrim (trimethoprim/sulfamethoxazole)
What is a common first line drug to treat UTIs?
Nitrofurantoin - Category B drug.
NOTE - not recommended for pyelonephritis.
Could also be cephalexin (keflex) or amoxycilin
What drug is most commonly used to treat syphilis?
Ben Pen, or doxycycline if allergic to Penicillin
What is aciclovir more commonly known as, and what is used for?
Zovirax - used to treat HSV-2 along with analgesia and topical anaesthetic gels.
Note - not in first 20 weeks - tend to use toward end of pregnancy to prevent outbreaks at time of birth.
What drug is used to treat toxoplasmosis?
spiramycin - to reduce risk of transmission to fetus.
Which drugs are used in thromboprophylaxis?
Asprin,
Heparin (unfractionated and LMW),
Warfarin
What are some differences between unfractionated and LMW heparin?
LMW - less adverse effects and equally effective in DVT prevention - now the preferred choice for prophylaxis.
Unfractionated - used in highest risk women. Requires lab monitoring of bloods.
Both are considered safe for the fetus in pregnancy and lactation - but some reports of miscarriage and prem labour.
Adverse affects of heparin?
Bleeding, Thrombocytopenia hypotension diuresis hyperkalaemia (aldosterone inhibition)
LT use: LFT abnormalities decreased renal function Hair loss (reverses) Osteoprosis heparin resistance withdrawal
When is LMW heparin discontinued in pregnancy?
Usually 24 hours prior to planned delivery, or at onset of labour.
How are osteoporosis, pregnancy and heparin related?
Osteoprosis can occur in pregnancy due to the increased demand for calcium by the fetus. This process can be compounded by heparin and women with Diabetes are particularly at risk.
Heparin binds to calcium ions and reduces bone formation!
Contraindications for heparin?
hypertension (increased risk of stroke) pre-eclampsia/eclampsia HELLP thrombocytopenia haemorrhagic disorders active haemorrhage
What is given if bleeding occurs with administration of Heparin?
The antidote is protamine sulfate - slow IV injection. Safety in pregnancy is unknown.
Side effects: warmth/flushing pulmonary vasoconstriction emesis BP and HR changes If given too fast - bradycardia and dangerous hypotension
What is warfarin?
An oral anticoagulant. High risk of fetal malformations, therefore rarely used in pregnancy.
Can be used postpartum following thromboembolic episodes.
How does warfarin prevent thrombosis?
It interferes with the action of Vitamin K, a precursor to clotting factors.
How does alcohol affect warfarin?
It inhibits the bodies ability to clear warfarin, therefore it can build up in the body resulting in haemorrhage.
Adverse affects of warfarin?
Bleeding - can give Vit K through slow IV, if major bleeding then need to give clotting factors
Skin necrosis - rare
Also - mouth ulcers, GI upset, liver damage, hypersensitivity such as urticaria, fever, nephropathy, decrease in WBC.
Effect of warfarin on the fetus?
Interferes with bone formation
2/3rd trimesters - fetal intracranial haemorrhage and subsequent malformation
High risk of spontaneous abortion, LBW, abdo and CNS malformation
What is clexane?
It is a type of LMWH. Generic name is enoxaparin sodium.
MIMS states category C drug.
What is fragmin?
LMWH - given by sub-cut injection.
Which drug is used to stimulate surfactant production in a preterm fetus?
Betamethasone - corticosteriod
What drug is used in neonatal resuscitation?
Adrenaline - 1:10000
Can be given by Umbilical vein catheter or ET tube.
What is caffeine citrate used and how is it given?
It is used in the prevention of apnoeic episodes in preterm infants.
Can be given orally or by injection.
Generic name: Methylxanthine
Adverse affects: NEC?
What is curosurf?
Exogenous surfactant given after birth to treat respiratory distress syndrome.
Adverse effects: bradycardia, hypotension, ET tube blockage and oxygen desaturation.
What are the effects of opioid use on the fetus?
Bradycardia, reduced variability and fetal movements in utero.
Developmental delay, lower IQ, attention deficits and behavioural problems
Effects of opioids in pregnancy?
PROM Abruption APH pre-eclampsia Stillbirth Prem birth LBW anaemia, resp depression at birth
Sudden withdrawal of opioids in pregnancy can result in?
Fetal death
PROM
convulsions
uterine contractions / prem labour
What are symptoms of opioid withdrawal in the neonate?
irritable and hyperactive abnormal reflexes rapid breathing fever tremor diarrhoea vomiting convulsions coma
What are the benefits of substitution of methadone and buprenorphine during pregnancy?
reduced IUGR
Stable mother
Methadone versus buprenorphine?
buprenorphine - associated with lower rates of preterm birth and withdrawal symptoms in neonates. BUT shorter half life = more frequent dosing.