Maternal Medicine Flashcards
PRE-ECLAMPSIA / ECLAMPSIA
description
- After 20 weeks gestation
- Reduced organ perfusion, vasospasm, endothelial activation
- Characterised by hypertension and proteinuria
- If untreated, convulsions can occur
- Severe cases may include hemolysis, elevated liver enzymes and low platelet counts (HELLP syndrome) in 20% of severe pre-eclampsia
PRE-ECLAMPSIA/ ECLAMPSIA
prevalence
- 5-8% of births
- 18% of maternal deaths
- Hypertensive disease occurs in 12-22% of pregnancies
PRE-ECLAMPSIA/ ECLAMPSIA
risk factors
- Prior history
- BMI >32.3
- African-american
- Nulliparity
- Older than 35
- Younger than 18
- Multi-fetal pregnancy
- Fetal hydrops
- Hydatidiform mole
- Thrombophilia
PRE-ECLAMPSIA / ECLAMPSIA
signs and symptoms
- Hypertension without proteinuria or oedema = gestational hypertension
- Hypertension with proteinuria or oedema = preeclampsia
- Hypertension with proteinuria or oedema and headache, abdominal pain, weight gain, visual disturbances, thrombocytopenia, oliguria, hemoconcentration, pulmonary oedema, proteinuria
- Hypertension, proteinuria or oedema and seuzires = eclampsia
PRE-ECLAMPSIA / ECLAMPSIA
differentials
- Chronic hypertension
- Transient hypertension
- Chronic renal disease
- Acute or chronic glomerulonephritis
- Coarctation of the aorta
- Cushing’s disease
- Systemic lupus erythematosus
- Periarteritis nodosa
- Obesity
- Epilepsy
- Encephalitis
- Cerebral aneurysm or tumour
- Lupuscerebritis
- Hysteria
PRE-ECLAMPSIA / ECLAMPSIA
investigations
- Liver and renal function studies
- Ultrasound to monitor foetal growth
- Assess fetal lung maturation
- Blood pressure, urinalysis
PRE-ECLAMPSIA
non pharmacological management
- Frequent prenatal visits, increased fetal surveillance, hospitalisation
- Only true treatment is delivery
- Bed rest with severe conditions
PRE-ECLAMPSIA
pharmacological management
- Glucocorticoids – fetal lung maturation
- Labetalol or nifedipine
- Magnesium sulfate – IV during labour to stabilise BP /reduce seizure risk
- IV hydralazine – lower BP during labour
ECLAMPSIA
management
- Keep woman alive during fit, prevent more fits, deliver the baby
- Magnesium sulphate reduces incidence and severity of fits
- During fit: turn woman on side, maintain airway, stop fit with iv diazepam and magnesium sulphate
- After the fit: prevent further fits by magnesium sulphate or diazepam infusion, lower BP with hydralazine, labetalol, magnesium sulphate, deliver aby
PRE-ECLAMPSIA/ ECLAMPSIA
outcome
- Improve after delivery but seizures can occur upto 10 days after delivery (unommon after 48 hours)
- Eclampsia: 25% of women with eclampsia have a fit before labour, they can be twitching (30secs) tonic phase (30secs), clonic phase (2 mins), coma (10-30mins) which can repeat frequently
PRE-ECLAMPSIA/ ECLAMPSIA
complications (maternal and foetal)
Maternal
- Cardiac decompensation
- Stroke
- Pulmonary oedema
- Respiratory failure
- Renal ailure
- Seizures
- Intracranial haemorrhage
- Coma
- Death (0.5-5% mortality)
Fetal
- Growth restriction and death
HYPERTENSIVE DISORDERS OF PREGNANCY
risks for mother
- Cerebrovascular accident.
- Renal failure
- Heart failure.
- Coagulation failure.
- Liver failure.
- Adrenal failure.
- Eclampsia
HYPERTENSIVE DISORDERS OF PREGNANCY
risks for foetus
- Asymmetrical intrauterine growth restriction.
- Placental abruption.
- Iatrogenic preterm delivery.
PREGNANCY INDUCED HYPERTENSION
hypertension occurring for the first time after 20 weeks’ gestation.
HYPERTENSION IN PREGNANCY definition
- Blood pressure of 140/90mmHg on two occasions more than 4 hours apart.
- A rise of more than 30mmHg in systolic blood pressure over the booking blood pressure.
- A rise of more than 15 mmHg in diastolic blood pressure over the booking figure.
GESTATIONAL HYPERTENSION
classification
- Mild: a blood pressure up to 140/100mmHg without proteinuria.
- Moderate: a blood pressure up to 160/110 mmHg without proteinuria. In the absence of pro- teinuria PIH is rarely dangerous to mother or fetus.
- Severe: a blood pressure of more than 160/ 110 mmHg; and the presence of proteinuria (pre-eclampsia/pre-eclamptic toxaemia (PET)).
PROTEINURIA IN PREGNANCY
definition
- More than 300mg on a 24-hour collection of urine.
- Oedema associated with hypertension and proteinuria is a sign of worsening pre-eclampsia. Oedema alone is of little significance.
HYPERTENSION IN PREGNANCY
prevelence
- 10-15% of primigravid women some form of hypertension
- 6% considered to have gestational diabetes
- 2% develop pre-eclampsia
PRE-ECLAMPSIA
aetiology
- Women who develop pre-eclampsia have a failure of the second wave of trophoblastic invasion.
- This failure probably leads to a local alteration of the prostacyclin : thromboxane ratio. Both these prostaglandins are produced by trophoblast and exert opposite effects. In gestational diabetes, the balance of the ratio appears to favour thromboxane. This leads to local vasoconstriction and platelet agglutination on already undilated vessels.
- The combination of the above two factors is associated with failure of the initial fall in peripheral resistance and hence blood pressure in mid- pregnancy is maintained —it normally shows a marked fall. Subsequent narrowing or clotting of the abnormal blood vessels leads to a further increase in peripheral resistance and hence hypertension.
- The narrowing of the blood vessels also leads to decreased perfusion of the intervillous space and hence the development of an asymmetrical small for gestational age (SGA) fetus.
PRE-ECLAMPSIA -how can prevelance be reduced
Antioxidants (vitamin C and E) in pregnancy have been shown to reduce the prevalence of pre-eclampsia in women who are at high risk— previous early onset of gestational diabetes, women with antiphospholipid syndrome.
clinical course of hypertensive disorders of pregnancy
- Gestational diabetes usually presents in primigravidae in late third trimester
- Usually no treatment or anti-hypertensive therapy
- Occasionally develops into pre-eclampsia
HYPERTENSIVE DISORDERS OF PREGNANCY mild 1. symptoms 2. BP 3. proteinuri 4. reflexes 5.fundi 6. renal 7.bloods
- none
- <140/100
- none
- normal
- normal
- normal
- normal
HYPERTENSIVE DISORDERS OF PREGNANCY moderate 1. symptoms 2. BP 3. proteinuri 4. reflexes 5.fundi 6. renal 7.bloods 8. treatment
- mild headache, oedema
- <160/110
- none
- normal
- nomal
- normal
- normal FBC, urate raised, LFT normal, clotting normal, foetus normal/SGA
- anti-hypertensives, ? delivery
HYPERTENSIVE DISORDERS OF PREGNANCY moderate 1. symptoms 2. BP 3. proteinuri 4. reflexes 5.fundi 6. renal 7.bloods 8. treatment
- frontal headache, oedema, visual disturbance
- > 160/110
- ++
- hyperreflexia
- papilloedema
- decreased urinary output
- HB up or down, decreased platelet, increased urate, LFT, prolonged clotting
- anti-hypertensives, anti-epiletics, MgSO4, delivery
TERATOGEN
- An agent which when administered to the pregnancy woman directly or indirectly causes structural or functional abnormalities in the foetus or in the child after birth
- May not be apparent until later in life
- Infections, physical agents/chemicals, medicines, alcohol, tobacco, cocaine
CONGENITAL MALFORMATIONS
- 2-3% in normal young fit healthy mothers
- Factors that increase the risk: Age, poor obstetric history, poor health, drugs, infections such as rubella
- Causes: genetic, chromosomal aberration, radiation, infection, maternal metabolic disorder, drugs and chemicals (4-6%)
CRITERIA FOR HUMAN TERATOGENS
- Defect associated with drug in a sufficient number of cases
- Distinctive pattern of defects
- Correlation with an animal model at equivalent doses
- Known teratogenic mechanism
EFFECTS OF TERATOGENS
- Chromosomal abnormalities
- Impairment of implantation of the conceptus-this mechanism is sometimes used in contraception
- Resorption or abortion of the early embryo
- Structural malformations
- Intrauterine growth retardation
- Foetal death
- Functional impairment in the neonate eg deathness
- Behavioural abnormalities
- Mental retardation
what is teratogenicity
The property or capability of producing congenital malformations
effect of tobacco on the foetus
Can cause vasoconstriction, hypoxia, CO poisoning leading to problems in foetal development and death
effect of cocaine on foetus
Causes vasoconstriction and hypoxia, bad for maternal health
what is behavioural teratology
Affect on the behaviour or functional adaptation of the offspring to its environment
what is transplacental carcinogeniticty
- No adverse effects on mother but cancer in offspring
- Eg diethylstilboestrol (DES) causes rare vaginal cancer
what are mutogenicity effects
- Germ cells-sex cells eg reduced fertility with each new generation and eventually infertility
- Somatic cell-all other body cells eg induction of cancer
mechanisms of teratogens
- May be beneficial or harmless to the mother but harmful or lethal to the embryo or foetus
- Time of exposure is critically important
- Susceptibility to some teratogens is genetically determined
- Teratogenicity is usually dose dependent
- Teratogenic agents may be synergistic
- A specific placental barrier does not exist
- Risk may be altered by individual variation in drug pharmacokinetic metabolism
- anacephaly
- syndactyly
- hypospadias
- brain and skull don’t develop
- fused fingers, webbing of skins or bones fused
- opening of urethra not at end of penis
what malformation would be produced with exposure to teratogen at the following days post conception
- 24
- 12-40
- 34
- anencephaly
- limb reduction
- transposition of great vessels
what malformation would be produced with exposure to teratogen at the following days post conception
- 36
- 42
- 84
- cleft lip
- ventricular septal defects, syndactyly
- hypospasias
FOETAL ALCOHOL SYNDROME
- Behavioural tetralogy
- Heavy alcohol intake in pregnant women
- Regular drinking or binge drinking
- 45ml alcohol/day=FAS in 2.2/1000 live births
- Often goes unnoticed as facial features are not always that obvious
- Attention span and lower academic ability often only noted at school
- Difficult to establish alcohol as the cause as there are many other contributory factors, strong behavioural link
FOETAL ALCOHOL SYNDROME
what advice is given to pregnant women regarding alcohol intake
- Vague
- No advisory body in England and Wales gives a clear recommendation to abstain from alcohol
- Safety approach is not to drink at all al during pregnancy, although drinking small amounts of alcohol after three months of pregnancy (not more than one or two units, no more than once or twice a week) does not appear to harmful
- department of health advice on alcohol: If pregnant or planning to get pregnant avoid alcohol altogether
- NICE advice on alcohol use in pregnancy: Avoid alcohol in the first three months
- What both DoH and NICE say about alcohol use in pregnancy: If you opt to have a drink you should stick to no more than one or two units of alcohol once or twice a week to minimise the risk to the baby
- royal collage of gynaecologists advice regarding drinking in pregnancy: The safest approach is not to drink at all during pregnancy, although drinking small amounts of alcohol after three months of pregnancy (not more than one or two units, not more than once or twice a week) does not appear to be harmful
SEX STEROIDS AND CONTRACEPTIVE AGENTS
- Oral contraceptives and progestins administered in the first trimester have been blamed for a variety of birth defects, but studies have not confirmed any teratogenic risk for these drugs
- Meta analysis of first trimester sex hormone exposure reveals no association between exposure and foetal genital malformations
ANDROGENIC STEROIDS
- Androgens may masculinise a developing female foetus
- Progestational agents, most often the synthetic testosterone derivatives, may cause clitoromegaly and labial fusion if administered before 13 weeks of pregnancy
SPERMICIDES
- Reported increased risk for abnormal offspring in mothers who has used spermicides for contraception has not been confirmed
- Exposed women had 23 infants with abnormalities (5%) compared with 4.5% in the nonexposed controls, which is not a significant difference
FIRST TRIMESTER DRUGS WITH FETOTOXIC EFFECTS
- Androgens: virilisation of female fetus
- Oestrogens: feminisation of male fetus
- Warfarin: nasal hypoplasia, skeletal defects
- Retinoids: craniofacial, cardiovascular and CNS defects
- Diethylstilboestrol: uterine lesions, transplacental carcinogen
- Antiepileptics: facial defects, mental retardation, neural tube defects
DOSE RESPONSE CURVE
- Exposure to teratogens follows a toxicological dose-response curve
- The small increments in dose can show large increase in effects eg methotrexate (cancer drug) generally be around 7.5mg, above this causes foetal toxicity
- Not only is the dose important, but also the route of exposure-topical, oral, parenteral
DRUG SYNERGY IN PREGNANCY
- Risk factors may not only additive but potentially synergistic
- Teratogenicity of a drug may be enhanced by co-administration of a second drug, or even by concomitant exposure to environmental chemicals
Multiple anticonvulsant therapy
- 1 drug-4% abnormalities
- 2 drug-6% abnormalities
- 3 drug -11% abnormalities
- 4 drug-11% abnormalities