General Obstetrics and Pregnancy Flashcards
What does the gestational age refer to?
Duration of pregnancy dated from first day of LMP which preceeds ovulation and fertilisation by about 2 weeks
What are the major functions of the placenta?
Maternal-foetal transfer of nutrients and oxygen
Clearance of foetal waste
Synthesis of proteins and hormones
Where does the exchange of substances occur between the mother and the foetus?
Across the placenta, where maternal blood surrounds the chorionic villus.
What are the side effects of smoking during pregnancy?
Increased risk of:
- Miscarriage
- Pre-term labour
- Stillbirth
- SUDI
- IUGR
What are the side-effects of alcohol in pregnancy?
Foetal alcohol syndrome Learning difficulties IUGR Post-natal restricted growth Microcephaly
Is occasional drinking or binge drinking worse for risk of foetal alcohol syndrome?
Binge drinking - it is a major risk factor for FAS.
What are the risks of taking cannabis during pregnancy?
Similar to smoking due to tobacco content.
Increased risk of IUGR, stillbirth, preterm labour, SUI, and miscarriage.
What are the risks to the mother of taking cocaine during pregnancy?
- Hypertension leading to pre-eclampsia
- Placental abruption
What are the risks to the foetus of taking cocaine during pregnancy?
Prematurity
Neonatal abstinence syndrome
What are the risks of taking heroin during pregnancy?
Neonatal abstinence syndrome - newborn withdrawal caused by in utero exposure to drugs of dependance.
What are the aims of preconceptual care?
To maximise maternal and foetal health during pregnancy, minimise the risks of pregnancy, and advise on appropriate steps for the mother to take.
What substances can a mother abuse during pregnancy?
Cigarettes/smoking
Alcohol
Illicit drugs e.g. cocaine, heroin, amphetamines, marijuana
What dose of folic acid should be prescribed for a woman planning a pregnancy, and how long for?
400 micrograms daily for at least one month pre-conception, and 3 months post.
What dose of folic acid should be prescribed for a high risk woman planning a pregnancy, and how long for?
5mg daily for at least one month pre- and 3 months post-conception.
Which women are in the high risk category for folic acid supplementation?
Epileptics
Obese women
Diabetic women
Women with PMH of neural tube defects
What is the first antenatal visit for?
To take the history from the mother and do early baseline observations for monitoring purposes throughout the pregnancy.
Also to give the mother advice about lifestyle and saftey-netting for the pregnancy.
They should be encouraged to ask any questions they might need/want to ask
What basic obs should be taken at the booking visit at the very minimum?
Maternal height and weight -> BMI
Maternal blood pressure
In an uncomplicated pregnancy, how many appointments should a nulliparous woman be given?
10
In an uncomplicated pregnancy, how many appointments should a parous woman be given?
7
What should be done at every antenatal appointment?
BP and urine sample for proteinuria
What are the risk factors for pre-eclampsia?
Previous history Nulliparous Multiple pregnancies Maternal age over 40 BMI over 35 Close FHx Pre-existing renal/cvs disease or diabetes
What is placental abruption?
Condition where part or all of the placenta become separated from the uterine wall prematurely.
What is the pathophysiology of placental abruption?
Rupture of the maternal vessels within the basal layer of endometrium. A haematoma forms which splits the placenta away from the endometrium. This compromises the placenta and causes foetal distress.
What are the 2 types of placental abruption?
Revealed - bleeding tracks downwards and drains through the cervix -> PV bleed.
Concealed - bleeding remains within uterus and forms a clot.
What are the major risk factors for placental abruption?
- Prev. placental abruption
- Pre-eclampsia/HTN
- Abnormal lie
- Polyhydramnios
- Abdo trauma
- Smoking/drug use
- Bleeding in first trimester
- Thrombophilias
- Multiple pregnancy
A woman who is 36 weeks pregnant presents with painful PV bleeding, pallor, distress, and generally feeling unwell. What re your differentials, and which is top and why?
- Placental abruption - painful PV blood loss with disproportionate symptoms of shock.
Placenta praevia
Marginal placental bleed
Vasa praevia
Uterine rupture
What history do you want to take from a woman with suspected placental abruption?
- Blood loss - how much and over what time period.
- Fresh or brown blood, any mucus
- Rupture of membranes?
- Reduced foetal movements
- Epigastric pain
- Risk factors
- Provoked? e.g. post-coital
A woman who is 36 weeks pregnant presents with painful PV bleeding, pallor, distress, and generally feeling unwell. How should this patient be managed?
ABCDE!!! She’s going into shock!
If a woman with suspected placental abruption is clinically stable, what should we examine for?
- Signs of shock (just incase)
- Tender abdomen
- “Woody” uterus
- Palpable contractions
- Lie and presentation of foetus
- CTG for foetal wellbeing
- External examination - avoid speculum until placenta praevia excluded, swabs for infection if bleeding minimal.
How should placental abruption be investigated?
Assess foetal and maternal wellbeing:
- Bloods - FBC, clotting, Rhesus status, G&S/crossmatch as appropriate, U&Es, LFTs (pre-eclampsia and HELLP eliminated)
- USS
- CTG if over 26 weeks gestation
How should placental abruption be managed?
ABCDE!!!
- Emergency delivery, usually by C section (unless delivery imminent or operative delivery achievable)
- Induction of labour if at term with no compromise of mother or foetus.
- Conservative if partial or marginal abruption with no maternal/foetal compromise
Always give anti-D within 72 hours if the mother is rhesus D negative
Define prolonged pregnancy.
Pregnancy which persists up to and beyond 42 weeks gestation.
What are the risk factors for prolonged pregnancy?
- Nulliparity
- Maternal age over 40
- Personal Hx of prolonged pregnancy
- High BMI
- FHx
What does prolonged pregnancy increase the risk of?
By how much?
Increased risk of stillbirth.
37/40 -> 1 in 1000
42/40 -> 3 in 1000
43/40 -> 6 in 1000
Why is the risk of stillbirth higher in prolonged pregnancy? What else does prolonged pregnancy increase the risk of?
Placental insufficiency and degradation
Foetal acidaemia
Meconium aspiration
Need for instrumental delivery or C-section.
What are the clinical features of prolonged gestation, aside from being past 42 weeks?
- Static growth
- Macrosomnia
- Oligohydramnios
- Reduced foetal movements
- Meconium
- Dry/flaky skin with reduced vernix
How do we manage prolonged pregnancy?
Delivery by 42 weeks by:
- Membrane sweeps from 40+0 nulliparous/41+0 parous
- Induction of Labour between 41 and 42 weeks
What do we do in prolonged pregnancy if the woman refuses induction of labour?
Twice weekly CTG monitoring and USS measuring amniotic fluid to check for foetal distress in case emergency c-section needed.
What happens in maternal isoimmunisation?
Mother’s immune system is sensitised to antigens on foetal erythrocytes resulting in the production of IgG antibodies.
What sensitising events can cause maternal isoimmunisation?
- Antepartum haemorrhage
- Abdominal trauma
- During delivery
When does maternal isoimmunisation tend to be a problem?
Rarely during primary exposure, but more commonly in subsequent exposures when maternal antibodies can cross the placenta and attack the foetal red blood cells.
What are the consequences of maternal isoimmunisation on the foetus?
Haemolysis -> foetal anaemia
What is the most common set of surface antigens capable of inducing maternal isoimmunisation?
Rhesus D when the mother is Rhesus negative and they have come into contact with rhesus positive foetal blood.
How can we prevent maternal isoimmunisation?
Administer Anti-D immunoglobulin which binds to RhD+ cells in maternal circulation so no immune response is stimulated.
When is anti-D Ig indicated?
Following a sensitising event to a RhD- woman:
- Invasive obstetric testing
- APH
- Ectopic
- External cephalic version
- Fall/abdo trauma
- Intrauterine death
- Miscarriage
- ToP
- Delivery
What blood tests should we do to determine rhesus status after a sensitivsing event?
Maternal blood group and antibody screen.
Foeto-maternal haemorrhage test (assess how much foetal blood has entered maternal circulation to determine how much anti-D should be given)
What is the minimum dose of anti-D that should be given to a mother following a sensitivsing event after 20 weeks gestation?
500 IU of anti-D Ig within 72 hours of event
What is the minimum dose of anti-D that should be given to a mother following a sensitivsing event before 12 weeks gestation?
250 IU anti-D within 72 hours of event
What is the minimum dose of anti-D that should be given to a mother following a sensitivsing event between 12 and 20 weeks gestation?
250 IU of anti-D
When do we check maternal blood group and do an antibody screen?
Booking visit and then again at 28 weeks.
When should prophylactic anti-D be given to a RhD- pregnant woman?
28 and 34 weeks gestation.
Define small for gestational age.
Infant with a birth weight below the 10th centile for its gestational age.
Sever = birth weight below 3rd centile.
Define foetal growth restriction.
When a pathological process has restricted the genetic growth potential of the foetus
What does low birth weight refer to?
Birth weight below 2.5kg
What can cause foetal growth restriction?
Placental insufficiency caused by low pre-birth weight, substance misuse, autoimmune disease, renal disease, diabetes, and chronic HTN.
Foetal factors such as chromosomal, structural, metabolic, or infective causes.
What are the risk factors for SGA?
Maternal age over 40 Smoking 11+ a day Previous SGA baby Parental SGA Previous stillbirth Cocaine use Daily vigorous exercise Maternal illness
How is SGA diagnosed?
USS then plot weight on customised growth chart.
Ratio of head circumference and abdominal circumference.
There is also often oligohydramnios as placental insufficiency can result in impaired renal function.
If SGA is suspected, how should we investigate?
- Detailed foetal anatomical survery
- Uterine artery Doppler
- Karyotyping
- Screening for infections
What can we do to prevent SGA in mothers with risk factors?
Modify risk factors - promote smoking cessation, optimise maternal disease, 75 mg aspirin from 16 weeks gestation if at risk of pre-eclampsia.
How is SGA monitored?
Uterine artery dopplers repeated every 14 days, unless abnormal.
Symohysis fundal height, CTG, amniotic fluid volume, and other measurments can also be used.
What are the indications for delivery with SGA according to UAD?
Under 37 weeks if absent/reverse end diastolic flow on Doppler. Deliver by C section.
By 37 weeks if abnormal UAD or MCA doppler
At 37 weeks if normal UAD
What are the neonatal complications of SGA?
Birth asphyxia Meconium aspiration Hypothermia Abnrmal blood sugars Polycythaemia Complications of prematurity
What are the long term complications of SGA?
Cerebral palsy T2DM Obesity HTN Precocious pubery Behavioural problems Depression Alzheimer's disease Increased risk of certain cancers
Define placenta praevia.
Obstetric condition in which the placenta is fully or partially attached to the lower uterine segment. Divided into major and minor.
What is the difference between major and minor placenta praevia?
Coverage of the cervical os - it is not covered in minor.
Why is placenta praevia a problem?
A low-lying placenta is more susceptible to haemorrhage, either from trauma or spontaneously.
Where should the placenta normally implant?
Usually the posterior uterine wall, always upper segment.
What is the main risk factor for placenta praevia, and why is it a risk factor?
Previous C section - the new placenta implants on the scar tissue.
What are the other risk factors for placenta praevia other than previous c section?
High parity Maternal age over 40 Multiple pregnancy PHx Hx of uterine infection Curettage of endometrium after miscarriage/termination
How might placenta praevia present?
- Picked up on antenatal scanning
- Antepartum haemorrhage
- Painless vaginal bleeding
What are the differentials for placenta praevia?
- Placental abruption
- Vasa praevia
- Uterine rupture
- Local genital causes of PV bleed
How should ?placenta praevia with antenatal haemorrhage be investigated?
ABCDE and resus if major bleed.
Bloods - FBC, clotting, rhesus test, G&S/Cross-match
Check for HELLP and pre-eclampsia
Assess foetal wellbeing (CTG)
USS for definitive diagnosis.
How should ?placenta praevia with antenatal haemorrhage be managed?
ABCDE!!!
C section at 38 weeks is safest mode of delivery, with anti-D administration within 72 hours if rhesus d negative.
If a woman is told she has placenta praevia at the 20 week scan, is that a definitive diagnosis?
No - as the foetus grows and the uterus stretches, the placenta can move upwards and no longer be in the lower segment. Keep an eye on this with subsequent scans to check progress. Diagnosis can be made if still in lower segment at 32-36 weeks (depending on if major or minor).
What is gestational diabetes?
Any degree of glucose intolerance with its onset during pregnancy, which usually resolves shortly after delivery.
Why does gestational occur?
Pregnancy hormones decreases fasting glucose levels, increases fat deposition, and increase appetite. Alongside that they cause increased insulin resistance. In women with GDM the body does not compensate enough by raising insulin production.
How is GDM diagnosed?
No set rules, but NICE recommends the woman has either:
- Fasting plasma glucose of 5.6 mmol/L or above
- Two-hour plasma glucose of 7.8 mmol/L or above
Is HbA1c used for diagnosis of GDM?
No
Why is gestational diabetes a problem?
Hyperglycaemia promotes large-for-dates babies, and there is increased risk of adverse foetal and maternal outcomes.
What are the increased foetal risks associated with GDM?
Increased birth weight Shoulder dystocia Birth injury Intensive neonatal care requirement Hyperbilirubinaemia
What are the increased maternal risks associated with GDM?
Preterm labour
Pre-eclampsia
Developing diabetes later in life
How common is GDM?
Quite - it occurs in 2-5% of pregnancies.
What non-modifiable factors increase the risk of GDM?
- Increasing age
- Asian/African-American/Hispanic/Latino/Pima Indians
What modifiable factors increase the risk of GDM?
- Smoking
- Inter-pregnancy weight gain
- Short interval between pregnancies
What obstetric history increases the risk of GDM?
- Previous macrosomia
- Previous unexplained stillbirth
What family history increases the risk of developing GDM?
-FHx of type 2 diabetes
Who should be offered screening for GDM?
BMI over 30 Previous baby over 4.5kg Previous GDM First degree relative with DM Ethnic background with high risk of DM
When does screening for GDM occur?
Offer at booking
Perform at 24-28 weeks