Antenatal Care and Screening Flashcards
Why is physiological adaptation necessary in pregnancy?
To allow the body to cope with the added strain of pregnancy
What are physiological changes in pregnancy responsible for?
So called minor ailments of pregnancy
Worsening of pre-existing illness
What percentage of women are affected by morning sickness?
80-85%
In what conditions is morning sickness worse?
Conditions where human chorionic gonadotrophin is higher e.g. twin pregnancy, molar pregnancy
What can morning sickness progress to?
Hyperemesis gravidarum (this risk is also increased when HCG is increased)
By what week of pregnancy does morning sickness usually improve?
16
How much does cardiac output increase by during pregnancy? Why is this?
30-50%
Due to combination of increase in SV and HR
What can the increase in heart rate in pregnancy be associated with?
Feeling of palpitations
At term, what must the blood flow to the uterus exceed?
1L/min
When does blood pressure drop in pregnancy?
During second trimester
Why does blood pressure drop during the second trimester?
Expansion of uteroplacental circulation
Fall in systemic vascular resistance
Reduction in blood viscosity
Reduction in sensitivity to angiotensin
When in pregnancy does BP usually return to normal?
In third trimester
Why does urine output increase in pregnancy, particularly in third trimester?
Bladder capacity is reduced in third trimester due to pressure in the pelvis from the expanding uterus
What is the increase in renal plasma flow and glomerular filtration rate in pregnancy?
Renal plasma flow increases by 25-59%
GFR increases by 50%
What is the change in serum urea and creatinine in pregnancy?
Both decrease
Due to increased GFR and dilutional effect of increased plasma volume
Why is there an easier path for ascending infection and increased pyelonephritis in pregnancy?
There is increased urinary stasis
When is hydronephrosis phsyiological in pregnancy?
In third trimester
Why is there a low threshold for MSSU and antibiotics for UTI in pregnancy?
UTI increases incidence of pre-term labour
Why is the incidence of anaemia increased in pregnancy?
Increased iron requirement from foeto-placental unit
When should iron supplements be given in pregnancy?
When Hb is < 110 at booking or < 100 on routine testing at 28 weeks
What is the increase in plasma volume and RBC mass in pregnancy?
Plasma volume 50%
RBC mass 25%
What is the increase in iron requirements in pregnancy?
1g
What does WBC increase to in pregnancy?
9,000-12,000
What does progesterone reduce?
CO2
What is the change in tidal volume, respiratory rate, plasma pH, O2 consumption and plasma PO2 in pregnancy?
TV - increases RR - increases plasma pH - increases O2 consumption - increases Plasma PO2 - unchanged
What is the change in oesophageal peristalsis and gastric emptying in pregnancy?
Oesophageal peristalsis is reduced
Gastric emptying slows
What happens to the cardiac sphincter in pregnancy?
Relaxes
What happens to GI motility in pregnancy? Why?
GI motility is reduced due to increased progesterone and decreased motilin
Ideally, who should be given pre-pregnancy counselling?
All women
How many pregnancies in Scotland are unplanned
1/3rd
For what women is pregnancy counselling vital?
Women with any previous health or pregnancy problems
In what ways are the causes of maternal deaths changing?
BMI is increasing, weight related causes more common
Death from cardiac disease is relevant in an age group where it wasn’t relevant before
Thrombosis would have been a cause of death in pregnancy but there are drugs which can prevent this and can be used in pregnancy so screening is important
What general health measures should be taken in pregnancy?
Improve diet Optimise BMI Reduce (stop) alcohol consumption Smoking cessation Folic acid
What might you need to consider when counselling a pregnant woman on smoking cessation?
Whether the partner/surrounding family smoke - will be more difficult for the woman to quit if she is surrounded by other smokers
What dose of folic acid should be given to pregnant women? Why?
400mcg, ideally for 3 months before becoming pregnant and then throughout pregnancy to reduce the risk of neural tube defects
How does obesity affect pregnancies?
Increased rates of poor outcomes including stillbirth and miscarriage
Affects function of uterus in pregnancy
Venous thromboembolic events more common
What does foetal alcohol syndrome cause?
Typical facial appearance
Learning difficulties
What is the routine advice given to pregnant women regarding alcohol?
Avoid alcohol consumption completely during pregnancy
What ages of the fertile population carry worse pregnancy outcomes?
At either end - teenagers and older women
Why are teenagers more likely to have worse pregnancy outcomes?
May have less social support
Less antenatal care
Poor general health due to smoking and alcohol
Why are older women more likely to have worse pregnancy outcomes?
More prone to pre-existing medical conditions and complications of pregnancy
Increase in chromosomal disorders with maternal age
Why should blood pressure be monitored in pregnancy?
For signs of pre-eclampsia
When does pre-eclampsia usually occur?
In a woman’s first pregnancy
What does grand multiparity predispose a woman to?
Postpartum haemorrhage
What substances can cause withdrawal syndrome in the baby when it is born and “cut off” from its supply?
Heroin
Methadone
Benzodiazepines
What should be done/considered in women with known medical problems during pregnancy?
Optimise maternal health
Remember psychiatric health
Stop/change any unsuitable drugs
Advise mother regarding complications associated with her medical problems
Occasionally may need to advise against pregnancy
Women with diabetes and epilepsy need to be counselled
What is phenylketonuria?
Error of protein metabolism which results in high levels of the amino acid phenylalanine
What does untreated phenylketonuria cause?
Mental development impairment
What needs to be done if a woman with PKU is pregnant?
She needs to re-start her low phenylalanine diet to prevent high levels reaching the developing foetal brain
How is the demand for thyroxine in women with hypothyroidism affected by pregnancy?
Demand is increased so dose may need to be increased
Why are normal thyroxine levels needed in pregnancy?
Needed for foetal brain development
Ideally, when should glucose control in women with diabetes be optimised?
Prior to conception
What changes need to be made in medication of women with diabetes who are taking oral medications?
Medications need to be switched to insulin
What pregnancy complications are diabetic mothers more at risk of?
Pre-eclampsia
Stillbirth
Macrosomic infant
Where should diabetic pregnant women be cared for in pregnancy?
Joint diabetic-obstetric antenatal clinic
What are renal patients more likely to develop in pregnancy than normal women?
Pre-eclampsia
Why might pre-eclampsia be difficult to diagnose in women with pre-existing renal problems?
They may already have proteinuria and hypertension
What effect does renal transplantation have on fertility?
Restores fertility as well as renal function
What is the main concern for women with epilepsy in pregnancy?
The effect of their anti-epileptic medication on the developing foetus - some medications e.g. sodium valproate are extremely teratogenic
What are the rules regarding sodium valproate treatment of epilepsy in women of child-bearing age?
Sodium valproate should not be given to women of child-bearing age where there is an alternative
Why is it important to review a patient’s medication history when pregnant/trying to conceive?
In order to identify any drugs contraindicated in pregnancy and see if drugs can be safely discontinued or modified
How does a previous Caesarean section delivery affect a woman’s safest mode of delivery for subsequent pregnancies?
If a caesarean was given for a non-recurring cause such as breech presentation the woman will normally be fine to undergo normal labour, if a woman has had 2 previous caesarians it is customary to deliver by elective caesarean again
What might a previous pregnancy indicate?
How a woman is likely to progress in subsequent pregnancies
Why is antenatal care important?
High quality antenatal care reduces foetal and maternal mortality
What do antenatal examinations aim to identify?
Problems with the mother and foetus, and any social problems
What problems are important to detect in the mother?
Pre-existing or developing illness
Problems of pregnancy e.g. anaemia
What does examination of the foetus allow?
Detection of some foetal abnormalities and foetuses that are small for their gestational age
What is included in routine enquiry after 20 weeks of pregnancy?
Asking the mother about foetal movements
What is done at every antenatal appointment?
Blood pressure and urinalysis
What does abdominal palpation of a pregnant woman allow?
Asses symphyseal fundal height Estimate size of baby Estimate liquor volume Estimate foetal lie Determine foetal presentation
Can also listen to foetal heart during this examination
What is important to tell patients when talking about screening for foetal abnormality?
Women are offered screening but it is not compulsory
Patients should be aware of potential repercussions
What does screening allow?
Conditions to be detected in a symptomless population
What infections can be screened for in pregnancy?
Hepatitis B
Syphilis
HIV
UTI
Why is it important to identify hepatitis B in pregnant women?
If women are infected you can provide both active and passive immunisation to the neonate at birth
Can also alert healthcare workers of the woman’s infectious status
What does congenital syphilis cause?
Intrauterine growth restriction, hepato-splenomegaly, anaemia, thrombocytopaenia and skin rashes
How does HIV infection affect pregnancy?
Prior knowledge of HIV status allows the use of antiretrovirals to reduce viral load
Delivery is usually by Caesarean section and breastfeeding is avoided to reduce vertical spread
What can happen when a rhesus-negative woman is carrying a rhesus-positive baby? (Due to the father being rhesus-positive)
The woman develops anti-D antibodies if the foetal red blood cells enter the maternal circulation, these cause the baby to become anaemic and can cause foetal death
What is offered to all rhesus-negative women? When?
Anti-D IgG, both prophylactically and after potentially sensitising events
What is the aim of the first visit ultrasound scan?
Ensure pregnancy is viable
Identify multiple pregnancy
Identify abnormalities incompatible with life
Offer and carry out Down syndrome screening
What is the purpose of the detailed anomaly scan?
Systematic structural review of the baby to identify problems that need intrauterine or postnatal treatment, not possible to identify all problems
What is the overall risk of Down syndrome?
1 in 700
What is the biggest risk factor for having a baby with Down syndrome?
Increasing maternal age
What must women and their partners be aware of prior to any screening taking place for foetal abnormality?
Screening only provides a risk of their baby being affected, not a definite answer
When is first trimester screening carried out?
At 10-14 weeks gestation
What does first trimester screening involve?
Maternal risk factors
Serum beta human chorionic gonadotrophin
Pregnancy associated plasma protein A
Nuchal translucency measurement
What is the detection rate of trisomy 21 in first trimester screening?
90%
What causes nuchal translucency to increase?
Increases with gestational age
Incidence of chromosomal abnormalities is related to size of nuchal translucency (rather than the appearance)
When is further testing for Down syndrome offered?
If risk is > 1 in 150
What are the options of further testing methods for Down syndrome?
Chorionic villus sampling
Amniocentesis
Non-invasive prenatal testing
When is CVS offered and what is the risk of miscarriage with this procedure?
Between 10-14 weeks
1-2% risk
When is amniocentesis offered and what is the risk of miscarriage with this procedure?
15 weeks onwards
Around 1% risk
How does non-invasive prenatal testing work?
Maternal blood taken
Can detect foetal cell free DNA and use this to look for chromosomal trisomies
What screening tests are available for neural tube defects?
Ultrasound
Biochemical screening - maternal serum tested for alpha fetoprotein
What is the purpose of the second trimester ultrasound?
Detecting foetal abnormality
Good screening test for major structural abnormalities but poor test for chromosomal abnormalities
What percentage of foetuses with T21 will have a normal detailed second trimester US?
50%
What percentage of foetuses with T18 will have a normal detailed second trimester US?
17%
What percentage of foetuses with T13 will have a normal detailed second trimester US?
9%
