Antenatal care and pregnancy surveillance Flashcards
In the UK/ high-income countries, what number of appointments do women in their first pregnancy, and women in their subsequent pregnancies, usually have with healthcare professionals?
- First: 10
- Second: 7
What determines whether a patient receives antenatal care from midwives or with other members of the MDT including obstetricians?
if no risk factors or obstetric problems may all be from midwives; if risk factors, health problems, obstetric problems or poor obstetric history → some antenatal care from obstetrician etc.
What is the first appointment that women have with healthcare professionals during pregnancy and when does this occur?
‘Booking’ appointment with midwife by 10 weeks’ gestation
What are the aims of the first, ‘booking’ appointment with the midwife?
- idetnfiy risks
- screen for abnormalities or illness
- develop rapport and encourage future attendance by ensuring positive experience
- key health promotion messages
- gain initial observations of mother - to compare with later deterioration
How can likely gestation of the pregnancy be established at the booking appointment before 10 weeks’ gestation?
establishment of first day of last menstrual period, and abdominal examination
What are 4 groups of risk factors to be identified at first appointment in pregnancy (booking appointment) that increase risk of obstetric problems or complications for mother or fetus?
- Personal history and current health
- Family history
- Obstetric history - previous pregnancies
- Current pregnancy
What are 7 risk factors for obstetric complications under the category of personal history and current health?
- History of subfertility and fertility treatment
- Medical conditions including diabetes, thyroid problems, epilepsy, asthma, heart disease, hypertension, renal disease, cancer
- Surgical history - gynaecological procedures, treatment to the cervix, breast surgery, abdominal surgery
- Raised BMI or very low BMI
- Mental health - bipolar disorder, postpartum psychosis, schizophrenia, depression, postnatal depression, anxiety disorders, eating disorders
- Lifestyle - smoking, non-prescription and prescription drug use
- Social difficulties - domestic abuse, financial difficulties, previous child-protection concerns
What are 3 family history risk factors for obstetric complications to be established at the first appointment in pregnancy?
- Pregnancy related: first-degree relative with congenital abnormality or genetic abnormality, pre-eclampsia, venous thrombosis
- Medical conditions - diabetes, heart disease, inherited conditions e.g. sickle cell anaemia, cystic fibrosis
- Mental health - first degree relative with postpartum psychosis, schizophrenia, bipolar disorder, severe postnatal depression or depression
What are 7 risk factors in the obstetric history for obstetric complications that should be noted at the first, booking appointment of pregnancy?
- Miscarriage at >14weeks, stillbirth or neonatal death
- Recurrent miscarriage (3 consecutive first-trimester losses)
- Premature birth or small for gestational age infant
- Pregnancy-related hypertension, gestational diabetes, rhesus isoimmunisation, antepartum haemorrhage
- Induction of labour - indication
- Operative birth (C-section or instrumental delivery), shoulder dystocia, breech birth
- Postpartum haemorrhage, retained placenta, OASI (obstetric anal sphincter injury)
What are 4 current pregnancy factors which are risk factors for obstetric complications that should be picked up at the first, booking appointment?
- Hyperemesis
- Vaginal bleeding
- Abdominal pain
- Findings from pregnancy ultrasound
What is the recurrence risk of postpartum psychosis if there is a personal history?
1 in 2-4 (background risk of 1 in 500)
What management of family history of blood disorders will be required?
relevant counselling and screening
What are 3 examples of pre-existing maternal medical conditions that will require multifisciplinary care planning and monitoring throughout pregnancy?
- Diabetes
- Thyroid conditions
- Epilepsy
What could require discussion of choices relating to delivery?
previous caesarean section
What type of management of obstetric complications risks may be needed? 3 types
- management of lifestyle risks: referral for smoking cessation support, dietetic support to promote healthy eating
- mental health risks e.g. bipolar disorder: liaison with mental health services to
- social difficulties: liaison with local social care/ voluntary sector organisations
What are 6 aspects of the general physical examination performed at the first antenatal appointment?
- BMI
- blood pressure
- heart rate
- auscultation of heart and lungs - in area with high incidence of heart and respiratory conditions
- abdominal examination to determine uterine size/abnormal masses/ scars
- urinalysis - protein and glucose (UTI, hyperglucaemia)
What are 6 aspects of further screening in addition to the general physical exam at the first antenatal appointment?
- FBC - anaemia and thrombocytopenia
- Blood group: ABO and rhesus status of mother, any red cell antibodies
- Haemoglobin electrophoresis - screen for thalassaemia and sickle cell anaemia
- Hepatitis B status
- Syphilis
- HIV
What are 5 symptoms/ forms of discomfort many women may experience during early stages of pregnancy that might cause worry?
- Nausea and vomiting (morning sickness)
- Lower abdominal discomfort
- Frequency of micturition
- Vaginal ‘spotting’ (small amounts of bleeding per vagina)
- Breast tingling or discomfort
In addition to identifying obstetric risks, the physical examination and initial screening tests, what else is important to discuss with a woman at the first antenatal appointment?
discussion about options for screening for chromosomal and structural fetal abnormalities
What should you explain to a woman about screening for Down syndrome/ screening generally at the first antenatal appointment? 3 aspects
- nuchal translucency testing between 11 and 14 weeks
- routinely offered fetal anomaly scan between 18 and 22 weeks
- advise initial screening won’t provide conclusive answer about abnormality but presents a risk factor so can make further decisions about testing - chorionic villus sampling or amniocentesis
How can you explore a woman’s readiness to make positive health behaviour e.g. stopping smoking, drinking alcohol, using drugs during pregnancy, eating healthily and being more physically active at the first antenatal appointment?
Motivational interviewing or brief intervention approaches
Provide clear info about impact of particular behaviours on maternal and fetal health, while remaining non-judgemental in approach
What are 6 potential effects of smoking in pregnancy?
- Miscarriage
- Premature birth
- Small for gestational age babies
- Stillbirth
- Sudden unexpected death in infancy (SUDI)
- Increased hospital admissions in first year of baby’s life
What group of problems is drinking alcohol during pregnancy related to?
spectrum of potential problems called Fetal Alcohol Spectrum Disorder (FASD)
What proportion of babies are believed to be born with effects from alcohol?
1 in 100
What type of lifelong problems can FASD have on an affected person?
Learning and bahvioural difficluties
What are 3 broad areas to cover with pregnant women at the first antenatal appointment regarding lifestyle?
- Alcohol, smoking, drugs
- Diet
- Physical activity and exercise
How can women be helped to achieve a balanced diet in pregnancy?
vitamin and mineral supplements
Which 2 particular vitamin supplements are recommended in all pregnant women in the UK and why?
- Folic acid 400mcg for the first 12 weeks to reduce risk of neural tube defects
- 5mcg daily vitamin D
Which type of vitamin supplements should pregnant women be warned to avoid and why?
vitamin A supplements - teratogenic
What is the advice about physical activity in pregnancy?
Same as for all adults in UK: 5 periods of moderate physical activity for 30 min each week e.g. walking, swimming, gardening, yoga
What are the benefits of physical activity in pregnancy?
helpful in maintaining and improving physical and mental health in pregnancy and may help to relieve some of the discomforts of pregnancy
What point in pregnancy is considered the second trimester?
12-20 weeks
What are the 4 key parts of antenatal care in the second trimester (12-20 weeks)?
- Follow up of results from initial blood tests
- Fetal anomaly screening at 18-22 weeks
- Instigating any treatment or further surveillance indicated by these results
- At each appointment in 2nd trimester: 4 key measurements recorded (maternal blood pressure, urinalysis, ask about pain or vaginal loss, ascultation of fetal heart from 18 weeks)
What 4 physical tests must be performed at each antenatal appointment throughout the second trimester?
- Maternal blood pressure measurement
- Maternal urinalysis
- Ask about any pain or vaginal loss
- Auscultation of fetal heart from 18 weeks
What should you ask at every antenatal appointment during the second trimester?
(any pain or vaginal loss)
woman’s wellbeing, both physical and emotional - helps identify which symptoms are of concern and require further investigation by asking about impact on woman’s life
What are 12 common problems/ ‘minor disorders’ of pregnancy?
- Nausea and vomiting
- Heartburn
- Haemorrhoids
- Constipation
- Pelvic girdle pain, sciatica, back pain
- Anaemia
- Carpal tunnel syndrome
- Bleeding gums - gingivitis/ gum disease
- Fatigue
- Itching
- Rashes
- Vaginal discharge
What should you monitor if a woman reports nausea and vomiting during pregnancy?
investigate severity through history taking
if more than occasional, monitor weight, dehydration (urinalysis), consider hospitalisation
When should you consider hospitalisation in a pregnant woman with nausea and vomiting?
if weight loss, dehydration
What should you exclude as a cause of nausea and vomiting in pregnancy?
urinary infection
What is the typical advice/ management for nausea and vomiting in pregnancy?
Eat little and often
Antiemetics can be safely prescribed
What are 4 aspects of management of heartburn in pregnancy?
- Antacids
- Monitor diet to identify which foods worsen or improve symptoms
- Eat little and often
- If persistent and not relieved with common treatments, consider H2 antagonists
What is the management of haemorrhoids in pregnancy?
over the counter treatments; avoid constipation through remaining well-hydrated and eating plenty of fruit and vegetables
What is the management of constipation in pregnancy?
OTC treatments; avoid constipation - good hydration, eat fruit and veg, increase dietary fibre
What is the management for pelvic girdle pain/ sciatica/ back pain in pregnancy? 3 aspects
- avoid over-abduction of hips
- refer for physiotherapy - prescribed exercises to relieve pain, improve mobility and strengthen muscles
- walking aids in more severe cases
What is the usual management of anaemia in pregnancy?
usually iron deficiency - prescribe iron supplement, improve intake of iron rich foods and monitor improvement
What are 4 aspects of the management of carpal tunnel syndrome in pregnancy?
- Monitor severity
- Exclude pre-eclampsia
- Refer for physiotherapy
- Wrist splints may be helpful
Why is gingivitis/ gum disease and bleeding more common in pregnancy?
hormonal changes
What is the management of bleeding gums in pregnancy?
careful oral hygiene and dental check up
At what point in pregnancy is fatigue most common?
first trimester
What should you screen for with fatigue in pregnancy and what is the management?
anaemia
encourage physical activity to improve sleep quality
What causes itching in pregnancy?
hormonal changes and stretching of the skin
What can severe itching in pregnancy sometimes indicate and when should you be particularly alert for this?
obstetric cholestasis - after 30 weeks
How can you confirm cholestasis in cases of severe itching in pregnancy?
biochemical testing
What are 2 key types of rashes in pregnancy?
- Polymorphic eruption of pregnancy (1:240 pregnancies)
- Pemphigoid gestationis (1: 10 000 pregnancies)
How does polymorphic eruption of pregnancy present?
abdominal urticaria and vesicles (with no bullae), rarely in umbilical area, sometimes extends to proximal limbs
How do you manage polymorphic eruption of pregnancy?
antihistamines and topical steroids
How does pemphigoid gestationis present in pregnancy?
pruritic erythematous papules, plaques and wheals spreading from periumbilical area to the breasts, thighs and palms
What is pemphigoid gestationis associated with?
fetal compromise
What is the treatment for pemphigoid gestationis?
antihistamines, topical steroids and systemic steroids
What is a common finding with vaginal discharge in pregnancy?
heavier discharge normal during pregnancy
When should vaginal discharge in pregnancy be investigated further and how?
if malodorous or accompanied by itching - vaginal swab for culture
What is a very important social and environmental factor to enquire about during a woman’s pregnancy and how must this be done?
- domestic violence or abuse
- ensure on at least one occasion during pregnancy, time alone with woman to enquire about home situation
What is a link between domestic violence and pregnancy?
research suggests it can begin or escalate in pregnancy
What are 5 social issues to consider for a woman during pregnancy?
- Domestic abuse
- Substance misuse
- Involvement with judicial system
- Homelessness
- Poverty
If any social issues arise during pregnancy how might this be managed?
talk to woman about need to make referral for social support through social services and/or voluntary sector organisation
Familiarise self with local safeguarding and child-protection procedures
At what point in pregnancy is the third trimester?
20 weeks to term
What are 5 things to assess for in the third trimester of pregnancy, in addition to the 4 key things during the second trimester too (BP, urinalysis, pain/vaginal loss, fetal heart auscultation)?
- Abdominal examination
- Presentation
- Evaluation of fetal growth
- Enquiry about fetal movements
- Polyhydramnios or oligohydramnios - assess with palpation and measurement
What does abdominal examination involve in the third trimester of pregnancy?
- inspection, palpation and auscultation of fetal heart using Pinard stethoscope or hand-held Doppler device
- If fetal heart can’t be heard, ultrasound can be done to assess fetal well-being
How should you try to auscultate the fetal heart during antenatal appointments in the third trimester?
Pinard stethoscope or hand-held doppler device
if doesn’t work, ultrasound
What is meant by presentation and how can this be determined at antenatal checks in the third trimester?
= part of the fetus overlying the pelvic brim (e.g. cephalic, breech, shoulder)
examination and palpation of uterus will idetnfy this
What 3 things about the fetus should be assessed with examination and palpation fo the uterus in the third trimester?
presentation, position, descent
What is meant by position (as opposed to presentation) in pregnancy?
while presentation is the lowermost part of the fetus presented to the pelvic brim, position refers to location of the point of direction with reference to the four quadrants of the maternal outlet
How can evaluation of fetal growth be performed in the third trimester?
at each appointment from 24 weeks onwards, healthcare professional should measure from pubic symphysis to fundus of uterus and plot measurement (symphysio-fundal height, FSH) on size chart.
(prior to that: ultrasound measures; 10-14 weeks CRL, 15-20 head circumference)
From which point should fetal growth be measured using SFH?
from 24 weeks onwards
What should you do if SFH is outside normal range or becomes static?
ultrasound examination should be offered
What is the usual trend in fetal movements during pregnancy?
tend to increase in frequency and strength until 32 weeks, then remain relatively stable until birth
What is an important thing to do to keep track of fetal movements?
encourage woman to become familiar with individual apttern of baby’s movements
advise that it’s a sign of baby’s wellbeing
What should you advise women to do if they become aware of any reduction in the baby’s normal pattern of movements?
lie down for an hour to rest and focus on baby’s movements - if continue to be reduced, seek advice from HCP
Why is it so important for a woman to contact an HCP if her fetal movements are reduced?
it can indicate fetal hypoxia and is a risk factor for intrauterine death
What should you do if a woman presents with reduced fetal movements?
face-to-face consultation with fetal heart rate monitoring by cardiotocography and selective use of ultrasound
What is polyhydramnios?
Increased amniotic fluid volume
How might polyhydramnios be identified at a third trimester antenatal appointment?
palpation and measurement
What should be done if polyhydramnios is suspected during routine antenatal care?
Refer for ultrasound scan
How is polyhydramnios definitively diagnosed?
Ultrasound scan, may be described by a single pool >8cm in depth and/or amniotic fluid index (AFI) >90th centile for gestational age
What is the amniotic fluid index (AFI)?
measurement of maximum depth of amniotic fluid in the four quadrants of the uterus
How common is polyhydramnios?
occurs in 0.5-2% of all pregnancies
What are 2 conditions that polyhydramnios is associated with?
- Maternal diabetes (pre-existing or gestational)
- Congenital fetal anomaly e.g. oesophageal atresia
What are 7 things that the risk of is increased by polyhydramnios?
- Placental abruption
- Malpresentation
- Cord prolapse
- Large for gestational age infant (association with diabetes)
- Requiring a caesarean section
- Postpartum haemorrhage
- Premature birth and perinatal death
How might oligohydramnios be detected from antenatal examination in the third trimester?
abdo palpation and measurement may suggest it; unlikely to be specifically suspected by clinical palpation but may ontribute to smaller than expected SFH measurement
What should be done if oligohydramnios is suspected?
refer for ultrasound
How is oligohydramnios definitively diagnosed?
ultrasound: when AFI <5cm or single cord-free pool of <2cm
What proportion of pregnancies are affected by oligohydramnios?
1-3% of pregnancies
What 5 negative outcomes that oligohydramnios is associated with?
- poorer perinatal outcomes
- prolonged pregnancy
- rupture of the membranes
- fetal growth restriction
- fetal renal congenital abnormalities
When does oligohydramnios usually present?
third trimester of pregnancy (or mid-trimester onwards if renal congenital abnormalities)
What negative effect may oligohydramnios indirectly cause?
fetal hypoxia as a consequence of cord compression
What are 4 important maternal health problems to monitor/ screen for in the antenatal period?
- Hypertension and pre-eclampsia
- Screening for anaemia
- Impaired glucose tolerance and diabetes
- Mental health problems
When and how are hypertension and pre-eclampsia screened for in pregnancy?
at each antenatal contact during the second and third trimester, blood pressure measurement and urine testing for proteinuria
Ask about symptoms: headache, visual disturbances, severe upper abdominal quadrant pain, significant facial/hand/ankle oedema
What are 4 symptoms that may be indicative of maternal hypertension in pregnancy?
- Headache
- Visual disturbance
- Severe upper abdominal quadrant pain
- Signficant facial, hand or ankle oedema
How is screening for anaemia in pregnancy undertaken?
Blood taken to assess FBC in third trimester - to identify anaemia and abnormal platelet count
(also taken in first trimester at booking appointment)
What is the definition of anaemia in pregnancy?
Hb < 105g/L
Why is there uncertainty about treating mild anaemia (Hb 90-100g/L) in pregnancy?
iron supplements may lead to GI side effects, and no proven benefits in absence of demonstrable iron deficiency
When do most maternity units recommend treating with iron and in what form?
recommend treating with oral iron if Hb <100g/L or is mean corpuscular volume low <80 fL, but advisable to estimate serum folate, vitamin B12 and ferritin before embarking on therapy
What is the only indication for IV iron (e.g. Ferrinject)?
if concerns regarding compliance or prohibitive side effects with oral supplements (e.g. constipation)
What other red cell condition are women screened for other than anaemia during pregnancy and when?
red cell antibodies at 28 weeks
When is a glucose tolerance test performed in the pregnancy?
if risk factors for diabetes or gestational diabetes, or found to have glycosuria during antenatal appointments (done in third trimester, urine tested in all 3)
What should be done antenatally for women with pre-existing mental illness who are pregnant?
refer to mental health team for additional support and care in pregnancy and the postnatal period
advice to continue medication/against if contraindicated in pregnancy - weigh risks and benefits of stopping medication or continuing
What is the risk of stopping medication for mental illness in pregnancy if it contraindicated?
high risk of relapse in late pregnancy and the postnatal period
What are 2 examples of drugs for mental health that increase risk of fetal abnormalities?
lithium and sodium valproate
What kind of mental health problems might women develop for the first time in pregnancy?
depression, anxiety disorders e.g. OCD and panic attacks
How should mental health be monitored in pregnancy by the antenatal team?
ask about emotional wellbeing at each contact. ask open questions to encourage honesty about feeling low/hopeless/anxious
What should be done for women who develop mental health problems during pregnancy?
monitor and offer additional support
What are 2 examlpes of risks of mental health problems during pregnancy?
- higher risk of developing significant mental helath conditions including postnatal depression
- suicide - one of the leading causes of maternal death in UK
What is the definition of prolonged pregnancy?
pregnancy beyond 42 weeks’ gestation
What proportion of pregnancies are considered prolonged?
10%
What are 2 risks associated with prolonged pregnancy?
- intrauterine death
- intrapartum hypoxia
What is the management for prolonged pregnancy?
induction offered between 41 and 42 weeks’ gestation; prior to formal induction of labour, offered vaginal examination for membrane sweeping
What should be done if women decline being induced beyond 42 weeks?
offer increased antenatal monitoring - twice weekly CTG and ultrasound estimation of amniotic volume
What are the 2 reasons why a fetus may be small for gestational age (SGA)?
- Genetically/ constitutionally small
- Pathological
If a fetus is small for a pathological reason, what is the term used to describe the phenomenon?
Fetal growth restriction (FGR) - previously IUGR
What is needed for a reliable diagnosis of SGA and GFR?
knowledge of gestational age
How can estimated date of delivery (and therefore gestational age) be calculated?
Time from first day of last menstrual period, provided cycle length is 28 days
How can you correct for menstrual cycles that are not 28 days when calculating estimated date of delivery?
if cycle is longer e.g. 35 then add 7 days to the date of the LMP (i.e. this will decrease your predicted gestational age - I think)
What are 3 issues with menstrual dating to work out estimated date of delivery?
- Dates may be inaccurately recalled
- Cycle may be irregular
- Bleeding in early pregnancy may be mistaken for menses
How is gestational age most acurately determined?
Ultrasound scan undertaken before 20 weeks gestation - reasonable to assume all fetuses of given gestational age are of a similar size up until this point (20 weeks)
What are the 2 most reliable measurements for dating when undertaking an ultrasound?
- Crown-rump length between 10 and 14 weeks
- Head circumference between 15-20 weeks
What is the definition of small for gestational age (SGA)?
fetus or baby whose estimated fetal weight or birth weight is below 10th centile
What is the definition of fetal growth restriction (FGR)?
a fetus which fails to reach its genetic growth potential
How does FGR present?
fetus whose growth on serial ultrasound scanning falls below a certain threshold; often implied as crossing of centiles on chart of fetal biometry
What are the 2 key measures used to determine if a baby has FGR on ultrasond?
- appear thin as measured by ponderal index (ratio of body weight to length)
- skin-fold thickness (a measure of subcutaneous fat) is reduced
What is the overlap/ distinction between SGA and FGR?
a proportion of SGA fetuses will be growth restricted but majority are constitutionally small
some growth-restricted fetuses will not be SGA i.e. growth failing but not below 10th centile
What are 3 types of factors which affect fetal growth?
- Fetal factors
- Materanl factors
- Placental factors
What are 4 fetal factors that affect fetal growth?
- Genetic: ethnicity, personal characteristics
- Chromosomal - decreased growth associated in association with fetal aneuploidy
- Fetal anomaly
- Congenital infection
Of maternal and paternal genes, which play a greater role in affecting fetal growht?
Maternal
Intrinsic drive to grow more related to maternal genome than paternal, and involves ‘genomic imprinting’
(large mothers often have large babies, but correlation between large men and baby is poor)
What are 6 maternal factors which can affect fetal growth?
- Pre-pregnancy maternal disease e.g. renal disease, essential hypertension
- Chronic hypoxia in mother e.g. congenital heart disease
- Drugs/ cigarette smoking (tobacco, heroin, cocaine, alcohol)
- Maternal disease in pregnancy e.g. pre-eclampsia
- Starvation of mother
- Birth at high altitude - decreased oxygen content
What are 2 placental factors that can affect fetal growth?
- Adequate/ inadequate invasion of maternal spiral arteries
- Adequate/ inadequate vascular function
What is an example of how ethnicity can affect fetal growth?
Asian mothers have smaller babies than European counterparts
What are 4 examples of chromsomal abnormalities with which small fetuses are often seen?
- Trisomy 18
- Trisomy 13
- Trisomy 21
- Triploidy
What are 2 problems with the fetal that often leads to small fetal size?
- Structural abnormalities of major organ systems
- Fetal infection: toxoplasmosis, cytomegalovirus, rubella, malaria
What, worldwise, is the most common cause of infection leading to FGR?
malaria
How much can smoking decrease neonatal weight?
approximately 150g on average
What are 2 examples of pre-existing maternal disease that can have an adverse effect on fetal growth?
- Renal disease
- Essential hypertension
What does adequate placental function depend on?
adequate trophoblastic invasion
What does the development of the placenta involve?
- First trimester: trophoblast cells invade maternal spiral arteries in the decidua
- Second trimester: secondary wave of trophoblast extends this invasion along spiral arteries and into myometrium
- Leads to conversion of thick-walled muscular vessels with high vascular resistance to flaccid thin-walled vessels with low resistance to flow
How can pre-eclampsia lead to fetal growth restriction?
there is failure of secondary trophoblastic invasion in second trimester, leading to subsequent placental ischaemia, atheromatous changes and secondary placental insufficiency
may be due to immunological interface between fetal and maternal cells
How can impaired trophoblast invasion be detected?
Can be inferred from Doppler studies of maternal uterine arteries
What should be done if impaired trophoblast invasion is detected using Doppler studies and why?
indication for serial ultrasound surveillance of fetal growth
impaired blood flow is associated with increased risk of delivering SGA baby
What is the overall effect of uteroplacental insufficiency?
decrease in nutrient supply to fetus causes hypoxic, hyypoglycaemic and acidotic fetus
fetus increases erythropoiesis to compensate for hypoxia and redistributes blood away from peripheral circulation, gut and liver towards the heart, brain and adrenal glands
What type of growth restriction will be seen in a baby with uteroplacental insufficiency?
normal growth in length and brain development but thin and little or no subcutaneous fat
Glycogen stores minimal
= asymmetrical growth
What should be done if a risk factors for SGA is identified?
serial ultrasound fetal biometry from 26-28 weeks onwards to diagnose poor fetal growth
What are 9 maternal risk factors for a SGA baby?
- age >40
- smoker >10 a day
- Cocaine use
- Previous SGA baby
- Previous stillborn baby
- Chronic hypertension
- Diabetes with vascular disease
- Renal impairmet
- Antiphospholipid syndrome
What are 7 current pregnancy complications or results that can lead to a SGA baby?
- Threatened miscarriage
- Pre-eclampsia
- Placental abruption
- Unexplained antepartum haemorrhage (especially if recurrent)
- Abnormal uterine artery Doppler waveform
- Low level of maternal Plasma-Associated Placenta Protein-A (PAPP-A) - component of Down syndrome screening
- Hyperechogenic fetal bowel (usually at time of fetal anomaly scan)
What are 2 groups of risk factors for a SGA baby?
- Maternal
- Current pregnancy complication or results
When does the fundus reach 1. the umbilicus and 2. the xiphisternum?
- Umbilicus: 20-24 weeks
- Xiphisternum: 36 weeks
From which point should the height of the uterine fundus be measured at each antenatal clinic visit?
from 26 weeks onwards
How can the symphysio-fundal height be used to calculate a very approximate gestational age?
height measured is approximatly equal to gestation in weeks
What can be used to interpret the symphysio-fundal height?
SFH charts
When is SFH an indication for further investigation and what does this involve?
if <10th centile or serial measurements suggest poor growth
ultrasound fetal biometry
How is ultrasound examination used when diagnosing SGA or FGR?
used to establish or refute diagnosis
What is the only way a certain diagnosis of FGR or SGA can be made?
can only be made postnatally (but not useful when planning care/ surveillance)
What are 3 measurements that should be taken when diagnosing SGA/FGR from ultrasound and what can they be used to calculate?
- Fetal head (circumference or biparietal diameter)
- Abdominal circumference
- Femur length
► estimate fetal weight
Which single measurement on ultrasound examination is best to diagnose SGA/FGR?
abdominal cicumference
(measurements below 10th centile have 80% sensitivity in prediction of SGA neonates in high risk pregnancies)
In which group, SGA and FGR, are the risks for the fetus more greatly associated?
FGR
Why would it be valuable to be able to distinguish between SGA and FGR?
because increased risks for fetus more associated with FGR than SGA
What are 4 risks of FGR to the fetus?
- Stillbirth
- Birth hypoxia
- Neonatal complications
- Impaired neurodevelopment
What is the best way to determine if a baby has FGR? 2 methods
plot two or more fetal measurements on chart of estimated fetal weight (or abdominal circumference) against gestational age
can either use
- specfic fetal growth rate or velocity charts
- customised/ individualised charts to a specific pregnancy (best way)
What are 3 examples of factors taken into account in customised/ individualised fetal growth charts?
- ethnicity
- parity
- maternal weight
How can a customised growth chart (for either fetal weight or abdominal circumference) be used to more accurately diagnosis FGR?
if below 10th centile on customised chart, fetus more likely to be genuinely growth restricted
can also see if growth drops off/stops increasing
Once SGA or FGR is diagnosed, what should be done?
evaluate other paremeters of fetal wellbeing; mostly require close observation
What is the main principle of management of SGA or FGR?
monitor the fetus and deliver at appropriate time
What are 4 methods which are options for fetal monitoring in SGA/FGR and which is the most valuable?
- Fetal movement charts
- Fetal cardiotocography (CTG)
- Biophysical scoring
- Doppler blood flow → most valuable
What are 8 steps of the usual management of FGR?
- Risk factors and/or abnormal SFH measurements identified
- Serial ultrasound screening
- Ultrasound confirmation that baby small or growth restricted
- Exclude fetal abnormality (unless done already at 20 week scan)
- Consider whether fetus SGA or FGR. Use Doppler studies
- Monitor with Doppler studies and CTG as appropriate
- Consider corticosteroids if <34 weeks and delivery anticipated
- Deliver if fetal demise anticipated; threshold strongly influenced by gestation
Why is fetal movement monitoring sometimes considered useful for monitoring SGA/FGR?
poorly nourished fetal will attempt to conserve energy by becoming less active
What particularly is worrying about fetal movements?
if there is a sudden change in the pattern
What should be done if a woman reports suddenly changed pattern of fetal movementS?
bring to attention of woman’s midwife or obstetrician
Why is the use of fetal movement monitoring limited for monitoring SGA/FGR?
formal movement counting not supported by scientific evaluation of its efficacy in reducing perinatal deaths
How useful is fetal CTG in monitoring SGA/FGR?
gives indication of wellbeing at particular moment but limited longer term value
routine use not associated with improved perinatal outcome
Why isn’t performing a biophysical profile (BPP) useful for monitoring FGR/SGA? 3 limitations
- predictive value of adverse outcomes is low
- test takes long time to carry out - sometimes up to an hour
- most fetuses with abnormal BPP also have abnormal umbilical artery Doppler flow
What is a biophysical profile?
prenatal test to check on fetal wellbeing; fetal heart rate monitoring, USS, breathing, movements, muscle tone, amniotic fluid level
What is a Doppler ultrasound used to assess in FGR/SGA?
Doppler ultrasound of umbilical artery used to assess downstream placental vascular resistance
How can you interpret the results of doppler ultrasound of the umbilical artery?
- Normal waveform (semi-quantitative pulsatility or resistance indices) indicates SGA fetus constitutionally small rather than growth restricted
- Reduction or loss of end-diastolic flow identifies fetus at high risk of hypoxia
- Absent end-diastolic flow (AEDF) suggest risk of perinatal death
Which artery is used for Doppler ultrasound monitoring in SGA/FGR?
umbilical
What is the benefit of using the umbilical artery to monitor high risk fetuses?
reduces perinatal morbidity and mortality
In addition to umbilical artery monitoring with Doppler ultrasound how else can Doppler studies be used? 3 ways
- Studies of fetal cerebral circulation - especially at term
- Examination of fetal venous system - for considering timing of delivery
- Doppler signals from ductus venosus (vein in fetal liver)
What will a Doppler study of fetal cerebral circulation show in a growth-restricted fetus?
increased cerebral flow (as blood redistributed towards brain in response to hypoxia)
Resistance increases again as hypoxia becomes more severe, possibly due to cerebral oedema
Why can it be useful to perform doppler examination of the fetal venous circulation?
provides useful information when considering timing of delivery
How can doppler signals from the ductus venosus be used in SGA/FGR?
vein within fetal liver; indirectly helps interpret function of right heart. abnormal ductus venosus waveforms herald fetal demise
What is the sequence involving 6 steps observed with progressive fetal hypoxia?
- Impaired growth
- Abnormal umbilical artery waveform
- Increased cerebral blood flow
- Abnormal ductus venosus flow
- Abnormal fetal heart rate pattern
- Fetal demise
What are the 9 steps of the decompensation cascade of FGR?
- Raised umbilical artery pulsatility index
- Absent end-diastolic flow
- Oligohydramnios
- Reduced movements
- Non-reassuring or pathological CTG
- Reversal of end diastolic flow
- Terminal CTG
- Hypoxaemia
- Acidaemia
Why does using Doppler ultrasound of the umbilical artery relate to the decompensation cascade?
Decompensation cascade starts with raised ultrasound pulsatility index - UA abnormalities are first to appear so makes sense to use it as main screening tool
What 2 types of monitoring are best to use after absent/ reduced end diastolic flow have occurred?
CTG and doppler studies of fetal vessels
How is timing of the delivery of a baby with FGR/SGA decided?
balancing risks of keeping baby in utero against risks of prematurity, but delivery is appropriate if one of 3 key criteria is met
What are the 3 key criteria that mean if 1 is met (in FGR or SGA) the baby should be delivered?
- CTG becomes abnormal: decelerations or reduced variability
- AEDF in umbilical artery with abnormal ductus venosus flow
- Reveral of end-diastolic flow
What should be done if FGR is suspected before 36 weejs and delivery anticipated?
give corticosteroids to mother to enhance fetal lung maturation
What are 3 considerations about the mode of delivery in SGA/FGR?
- Placental reserve for fetuses may be extremely low, careful monitoring in labour required
- Early recourse to C-section appropriate if montiroing shows signs of fetal compromise
- Pre-labour C-section may be appropriate if significant pre-labour concerns about fetal wellbeing e.g. AEDF or REDF in UA
What are 8 possible complications of FGR?
- Perinatal asphyxia
- Operative delivery
- Perinatal death including stillbirth
- Neonatal hypoglycaemia and hypocalcaemia
- Necrotising enterocolitis
- Long-term handicap e.g. neurological due to intrapartum hypoxia
- Clumsy and lower IQ
- Non-insulin-dependent diabetes and coronary artery disease in adult life
Why is FGR thought to lead to type 2 diabetes and coronary artery disease in later life?
- fetus may alter metabolism to cope with poor nutrition in utero and therefore less able to cope with normal carbohydrate levels in later life
- vascular compensatory changes with FGR that predispose to later arterial disease
What is the diagnosis of FGR dependent upon?
at least 2 ultrasound scans at least 3 weeks apart
