Antenatal care and screening Flashcards
What percentage of woman are affected by morning sickness?
80-85%
Which conditions can make morning sickness worse?
Anything that raises human chorionic gonadotrophin e.g. twins or hydatidiform molar pregnancy
What can morning sickness progress to?
Hyperemesis gravidarum
When does morning sickness usually get better?
After the first trimester (Or after the first 16 weeks)
What happens to cardiac output during pregnancy? Why is there a change?
Cardiac output increases by 30-50% due to an increase in the heart rate from 70 to 90bpm
In terms of cardiac issues what is a common complaint during pregnancy and why can this be an issue?
Palpitations, differentiating between changing physiology and pathology can be hard.
What happens to blood pressure throughout the pregnancy?
It rises during the second trimester but returns to normal by the third
Why does the blood pressure rise during the second trimester?
> Expansion of the uteroplacental circulation
A fall in systemic vascular resistance
A reduction in blood viscosity
A reduction in sensitivity to angiotensin
What happens to the bladder capacity during pregnancy, when does this occur?
The bladder capacity is reduced during the third trimester due to the increase in pressure of the pelvis by the ever expanding uterus.
What happens to urine output during pregnancy?
Increases
Why does urine output increase during pregnancy
> Renal plasma flow increases by 25-50%
> Glomerular Filtration Rate increases by 50%
What changes to serum urea and creatinine are their during pregnancy and why does this occur?
There is a decrease due to the increase in glomerular filtration rate and partly due to the dilution effect of increased plasma volume.
What urinary condition other than increased urine output are pregnant woman at higher risk of?
1) Urinary tract infections
2) Pyelonephritis
Why are pregnant woman at higher risk of UTI’s?
There is an increase in urinary stasis
Why are pregnant woman at higher risk of pyelonephritis?
As hydronephrosis is physiological during the third trimester which increases the risk of pyelonephritis.
What can UTis/pyelonephritis increase the risk of?
Preterm labour
During pregnancy what happens to plasma volume?
Increases by roughly 50%
During pregnancy what happens to RBC mass?
Increases by roughly 25%
What does an increase in the plasma volume and RBC mass lead to?
A drop in the haemoglobin by dilution from 133 to 121g/L
What happens to the iron requirement during pregnancy and why?
Increase by 1g, most of increased iron requirement is for the fetoplacental unit
When should iron supplements be given in pregnancy ?
If HB is <110 on routine testing at 28 weeks
What happens to the platelet count during pregnancy and why?
Falls by dilution
What happens to the white blood cell count in pregnancy?
Increases slightly from 9000 to 12000 uL
What is the effect of progesterone on the respiratory system?
Acts to centrally reduce CO2 by:
> Increasing tidal volume
> Increasing respiratory rate
> Increasing plasma PH
What effect does pregnancy have on O2 consumption?
Increase by roughly 20%
What effect does pregnancy have on plasma PO2?
None, its unchanged
What effect does pregnancy have on the respiratory mucous membranes?
Hyperaemia
What effect does pregnancy have on peristalsis?
> Reduces oesophageal peristalsis
> Gastric emptying is also slowed
Why is GI motility reduced during pregnancy?
1) Increase in progesterone
2) Decrease in motilin
In Scotland, what percentage of pregnancies are unplanned?
33%
When is pre-planning pregnancy vital?
Ideally everyone would be screened.
However for those with pre-existing health issues or past issues with pregnancy it is vital
What are the major causes of death during pregnancy?
> Cardiac issues
Sepsis
Thrombosis
Neurological issues
What is more common in obese pregnancies?
> Miscarriage > Still borns > Uterus dysfunction during Labour > Venous thromboembolic events > Issues in routine measurements
What is done/talked about during pre-pregnancy counselling?
> General health measures:
- Diet
- BMI
- Alcohol consumption
> Smoking cessation advice
> Folic acid levels
> Confirm Rubella immunity
> Risk assessment:
- Age (Old or young)
- Parity (Pre-eclampsia)
- Occupation
- Substance misuse
> Medication review
> Pschiatric assessment
> Advice on current and future medical problems
What is phenylketonuria and what does it put a newborn baby at risk of?
An inborn error of protein metabolism of the essential amino acid phenylalanine.
It increases the risk of mental developmental disorders.
If a mother has phenylketonuria what should she do during pregnancy?
Have a low phenylalanine diet to prevent high levels reaching the developing fetes and putting it at risk of mental development disorders.
What is the most common thyroid disease encountered during pregnancy? What should be taken into account?
Hypothyroidism, the patient will require a higher dose of thyroxine. Normal levels are required for the fatal brain development
If a type two diabetic woman gets pregnancy what needs to be done?
> Diabetic mothers are at higher risk of eclampsia, stilbirth and amcrosomic infants.
> They should have their oral medications changed to insulin.
> There should be tight control of the blood glucose levels.
What are renal patients more likely to develop when pregnant?
Pre-eclampsia, this can be hard to diagnose due to already having proteinuria and pre-existing hypertension
What is the main concern of patients with epilepsy and pregnancy?
Their medications on the developing fetus.
What is Sodium valproate associated with in pregnancy?
An increased risk of spina bifida for the baby
After how many caesarian birth is it customary to choose elective caesarian delivery?
After 2 c-sections
What is the role of the antenatal examination?
Aims to identify problems of the mother, fetus or social issues
What may be tested in an antenatal examination?
> Routine enquiry
> BP
> Urinanalysis
> Diabetes
> Abdominal palpitation:
- Asses how baby lies (Fetal presentation)
- Symphyseal fundal height (SFH)
- Size of baby
- Liquor volume
> Listen to metal heart
> Screen for infection
> Iron-deficiency anaemia
> Isoimmunisation:
- Rhesus disease
- Anti-C, Anti-Kell
If a baby is still breeched at 36 weeks what is usually done?
Firstly ECV is offered. If this fails then elective caesarian is then offered.
Which infections are screened for in pregnancy?
1) Rubella
2) Syphilis (Easily treated with penicillin)
3) Hepatitis B (If infected passive and active immunisation for the baby)
4) HIV (Maternal treatment and careful planning reduces the risk of vertical transmission)
5) MSSU (UTI)
What can congenital rubella syndrome lead to?
> Mental handicap
Blindness
Deafness
Heart defects
What can congenital syphilis lead to?
> Intrauterine growth restriction > Hepato-splenomegaly > Anaemia > Thrombocytopenia > Skin rashes
What is looked for in the first visit scan?
> Is pregnancy viable?
Multiple pregnancy
Identify abnormalities incompatible with life
Offer and carry out Down syndrome screening
What is the overall risk of Down syndrome?
1 in 700
What is the risk of Down syndrome in a woman pregnant at 20 years old?
1 in 1667
What is the risk of Down syndrome in a woman pregnant at 45 years old?
1 in 30
What are the biggest determining factors in a baby having down syndrome?
> Maternal age = Older leads to an increased risk
> Family history = Translocation in some family members
What does screening for Down syndrome offer?
It only provides a risk of the baby being affected not a definitive answer.
Further testing will be offered to confirm.
When it the first trimester screening carried out?
Between 10 and 14 weeks gestation
What is tested at the first trimester screening?
> Maternal risk factors > Serum B-hCG > Pregnancy associated plasma protein A (PAPP-A) > Fetal nuchal translucency (NT) > Trisomy 21
What are the rates for detection of Trisomy 21 at the first trimester screening?
85-90% detected, with a 5% false positive rate.
What is a normal nuchal translucency measurement?
45-84mm
What is used within nuchal transluceny ?
The size rather than the translucency.
If there is higher nuchal translucency what may be done?
1) CVS:
- Performed at 10-14 weeks
- 1-2% risk of miscarriage
2) Amniocentesis:
- 15 weeks onwards
- 1% risk of miscarriage
3) Non-invasive pre-natal testing:
- Maternal blood taken
- Look for fatal cell free DNA, chromosomal trisomies
If there is a high risk of neural tube defects what is offered to the pregnant woman?
5mg folic acid supplementation
In terms of neural tube defects what can be detected in the first trimester US screening?
> Anencephaly
> Spina bifida sometimes
In second trimester what is tested to detect neural tube defects?
> Maternal serum us tested for alpha fetoprotein (>2.0MoM is high risk and warrants investigation)
> US will detect 90% of NTDs
What is the main goal of the ultrasound in the second trimester (20weeks)?
Detection of fatal abnormalities
What cannot always be detected in second trimester US?
Chromosomal abnormalities:
> 50% of fetuses with T21 will have a normal detailed USS
> 17% of fetuses with T18 will have a normal detailed USS
> 9% of fetuses with T13 will have a normal detailed USS
What is the first ultrasound sign of a pregnancy?
> Thickening of the lining of the womb.
What an be seen at 4.5 weeks gestation on US.
A fluid filled intrauterine gestational sac appears
What an be seen at 5 weeks gestation on US.
A yolk sac appears within the uterus
What an be seen at 5.5 weeks gestation on US.
A tiny fatal pole
What an be seen at 6 weeks gestation on US.
Fetal heart pulsation may be visible
Once a fetal pole is identified what is measured?
Crown rump length (CRL) measurement is made from one end of the embryo to the other
What can the crown rump length give as indication of?
The length correlates closely to gestational age, therefore it can be used to estimate the due date
What is testing in first trimester US?
> Gestational age > Miscarriage > Multiple pregnancy > Early abnormalities (Hydatidiform mole, ectopic pregnancy) > Some major structural abnormalities > Neural tube defects (Anencephaly, spinal bifida) > Examine maternal ovaries > Ectopic pregnancy
Estimated date of delivery can really be established by?
1st trimester USS, using the crown rump length.
What is the first sign on pregnancy on USS?
Thickening of the lining of the uterus
Fatal heart pulsation can be seen on transvaginal USS by?
6+ weeks gestation
How is gestation age calculated in the first trimester?
Crown rump length
When should the first US visit be performed?
At 11-12 weeks gestation
When is the CUB (combined ultrasound and biochemical) screening carried out in Grampian?
Between 11 and 14 weeks
If a patient books their first screening after 14 weeks what will be tested within their blood?
Serum markers:
1) Alpha feto-protein (AFP)
2) Total human chorionic gonadotrophin (hCG)
3) Unconjugated eostriol (UE3)
4) Inhibin-A
This is known as the quadruple test and is carried out between 15-20 weeks
What is the detection rate of the quadruple test?
Carried out between 15-20 weeks, the quadruple test carries a 75% sensitivity.
Tests for serum markers:
1) Alpha feto-protein (AFP)
2) Total human chorionic gonadotrophin (hCG)
3) Unconjugated eostriol (UE3)
4) Inhibin-A
What is the usual cut off for considered high risk in a pregnancy for trisomy?
1 in 200
If there is a high risk reporting of 1 in 200 what is offered?
An invasive test, usually amniocentesis, to identify fatal chromosomes and make a definitive diagnosis.
What is the risk of a miscarriage with invasive testing (e.g. aminocentesis)?
1% risk of miscarriage
What is nuchal translucency?
The measure of the fluid-filled area at the back of the baby’s neck
It is often used in combination with Human Chorionic Gonadotrophin (hCG) and Pregnancy Associated Plasma Protein-A (PAPP-A) in the maternal blood to calculate a risk of chromosomal abnormality.
Which tests may be combined with US in combined ultrasound and biochemical test (CUBS) ?
1) Human Chorionic Gonadotrophin (hCG)
2) Pregnancy Associated Plasma Protein (PAPP-A)
Used to calculate a risk of maternal chromosomal abnormality
What is the sensitivity of combined ultrasound and biochemical test (CUBS) in identifying Trisomy 21 (Down syndrome)?
Detects around 85% of cases and carries a false positive rate of 5%
Which biochemical marker may be used to determine neural tube defects (Spina bifida)?
Alpha fetoprotein (AFP) at second trimester screening between 15-20 weeks
What is considered an abnormal AFP?
An Alpha fetoprotein, >2.0 multiples of the median (MoM) is considered abnormal and will detect 85% of NTDs (Neural tube defects)
What rate of sensitivity does USS carry for NTDs?
USS will detect >90% of neural tube defects
What is myelomeningocele?
Spina Bifida
Where is AFP (Alpha fetoprotein) produced?
AFP is a fetal glycoprotein produced sequentially by the yolk sac, fetaI gastrointestinal tract and liver.
When is second trimester screening offered?
15-20 weeks
Which fatal parameters are used to monitor fatal growth?
> Head circumference
Abdomen
Femur length
Why may a third trimester scan be offered?
> Confirm/monitor structural abnormalities
Help in deciding delivery plan E.g. Looking at the lie of the baby ad whether C-section would be advisable
Check/monitor placenta issues
Size of the baby E.g. Static growth? Large, is mum diabetic?
How frequently would you expect to scan to monitor fatal growth?
> Spaced a minimum of 2 weeks apart but usually 4 weeks
True or false. Most structural anomalies can be picked up on first trimester?
False, most seen on second
True or false. A 2nd trimester USS will detect 75% of CNS structural abnormalities?
True
True or false. Detailed scan at 20 weeks is offered so that major structural anomalies can be recognised?
True
True or false. Detailed scan at 20 weeks will detect at least 50% of structural cardiac defects?
False, it is closer to 15% of cardiac abnormalities
True or false. PAPP-A is a protein raised in the maternal serum if the foetus has an open neural tube defect?
False, PAPP-A is used to determine Chromosomal abnormalities e.g. Trisomy 21
Alpha fetoprotein is used to determine NTDs
True or false. Third trimester USS is routinely performed at 28 weeks?
False, third trimester is not routinely performed
True or false. Detailed scan at 20 weeks will detect at least 50% of structural GIT abnormalities?
False, it is closer to 40%
True or false. Detailed scan at 20 weeks will detect at least 50% of structural MSS abnormalities?
False, it is closer to 25%
If the foetus head is lemon shaped (frontal bossing), banana shaped cerebellum and enlarged ventricles what does this indicate?
A neural tube defect
What does a cystic hygroma of the neck associated with?
Chromosomal abnormality
What does the presence of abdominal organs in the chest indicate?
Diaphragmic hernia
What does a double bubble sign indicate?
Duodenal atresia
In addition to NTDs AFP is elevated in a number of other situations, what are they?
These include incorrect gestational age, multiple pregnancy, bleeding in pregnancy, fetal death and abdominal wall abnormalities.
If abdominal contents are seen to have herniated into the umbilical cord what is the called?
Exomphalos
If the bowel is shown to have herniated through the abdominal wall alongside the cord what does this indicate?
Gastroschisis
What may a third trimester USS be performed?
To ensure fetal well-being, it is not routine. It is usually indicated it the baby feels large or small
What may be measured during a third trimester USS?
1) Measurements of the head, abdomen and femur and plotting standardised growth charts
2) Liquor volume (Fluid round baby)
3) Placental site
