Antenatal care and screening Flashcards
Why do physiological changes occur during pregnancy?
It is essential to allow the body to cope with the added strain
How many women are affected by morning sickness when they are pregnant?
80-85%
When do symptoms of morning sickness normally improve?
By 16 weeks
What happens to cardiac output during pregnancy?
It increases by 30-50% - HR increases from about 70-90bom
What symptom can pregnant women get as a result of highly increased cardiac output?
Palpitations
What happens to blood pressure in the second trimester?
It drops
What causes reduction of blood pressure in the second trimester?
Expansion of the uteroplacental circulation
Fall in sytemic vascular resistance
Reduction in blood viscosity
Reduction in angiotensin sensitivity
What happens to urine output in pregnancy?
It is increased - Renal plasma flow increases by 25-50%
GFR increases by 50%
Serum urea and creatinine decrease
What happens to bladder capacity in the third trimester?
It is reduced to do increased pelvic pressure from the expanding uterus
Why is there increased risk of UTI during pregnancy?
Increase in urinary stasis
Hydronephrosis is physiological which leads to pyelonephritis being more common
Why is anaemia common during pregnancy?
Plasma volume increases by 50% and RBC mass increases by 25%, leading to an overall drop in haemoglobin due to dilution
How much are iron requirements increase by in pregnancy?
1g
What effect does increased progesterone have on the respiratory system during pregnancy?
Reduces CO2 by increasing tidal volume and respiratory rate, leading to an increase in plasma pH
Oxygen consumption is increase by 20% byt PO2 of oxygen in plasma is unchanged
What effects does pregnancy have on the GI system?
Oesophageal peristalsis is reduced
Reduced rate of gastric emptying
Cardiac sphincter relaxes
GI motility decreases due to increased progesterone and decreased motilin
What symptoms may women experience as a result of GI changes?
Constipation due to reduced rate of gastric emptying
Heartburn/GORD due to relaxation of cardiac sphincter
What is the most common cause of death in pregnancy?
Cardiac disease
What advice are women given in pre-pregnancy counselling?
General health measures - improve diet, optimise BMI, reduce alcohol consumption
Smoking cessation
To take 400mcg folic acid each day
How are women advised in pre-pregnancy counselling in regards to known medical problems?
Optimise their health
Look after their psychiatric health
Stop or change unsuitable drugs
Advise regarding complications associated with maternal medical problems
Occasionally advice against pregnancy ie diabetes or epilepsy
What problems are to be identified during antenatal examination?
Problems with the mother
Problems with the fetus
Social problems
What problems can be identified with the mother in antenatal examination?
Pre-existing or developing illness
Common problems of pregnancy such as anaemia
What fetal problems can be identified in antenatal examination?
Small for gestational age
Fetal abnormality
What social problems can be identified in antenatal examination?
Offer support if needed
Domestic violence
Psychiatric issues
What is examined in antenatal examination?
Routine enquiry
Blood pressure
Urinalysis
Abdominal palpation - assess symphyseal fundal height, estimate size of baby
Determine fetal presentation - listen to fetal heart
What infections can be picked up through antenatal screening?
Hepatitis B Syphilis HIV UTI Rubella
What is done when screening by ultrasound on the first visit scan?
Ensure pregnancy is viable - no miscarriage
Identify if it is a 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
How does maternal age impact risk of down syndrome?
As maternal age increases risk increases
What is used in Down Syndrome screening?
Maternal risk factors - Serum beta-human chorionic gonadotrophin, pregnancy associated plasma protein, and fetal nuchal translucency measurement
When is a pregnancy considered to have high risk of Down Syndrome?
When the risk is greater than 1 in 150
What is non-invasive prenatal testing for Down Syndrome?
Maternal blood is take, fetal cell free DNA is detected and examined for trisomies
What are positives and negatives of second trimester USS?
It is very good for detecting major structural abnormalities but very poor for chromosomal abnormalities
What happens to white cell count in pregnancy?
It increases
What happens to platelet count in pregnancy?
Decreases due to dilution
If a woman is pregnant and has previously delivered 2 babies through cesarean, can she deliver via spontaneous vaginal birth?
No - must have elective cesarean
What should be done in pre-pregnancy counselling regarding maternal complications of previous pregnancies?
Counsel about risk of recurrence, especially of - Required C section, DVT, and preeclampsia
Actions to reduce risk - Thromboprophylaxis, low dose aspirin
What should be done in pre-pregnancy counselling regarding fetal complications of previous pregnancies?
Counsel about risk of recurrence, especially of - pre-term delivery, intrauterine growth restriction, fetal abnormality
Actions to reduce risk - Treatment of infection, high dose folic acid, low dose aspirin
What is the first sign of pregnancy on ultrasound?
Thickening of the endometrium
What is tested for in the bloodspot test when a neonate is born?
Phenylketonuria
Cystic fibrosis
Hypothyroidism
What happens at 4.5 weeks pregnancy on ultrasound?
Fluid filled intrauterine sac appears
What happens at 5 weeks pregnancy on ultrasound?
Yolk sac appears within the uterus
What happens at 5.5 weeks pregnancy on ultrasound?
Tiny fetal pole is visible
What happens at 6 weeks pregnancy on ultrasound?
Fetal heart beat becomes visible
How is gestational age and therefore estimated due date determined?
Once the fetal pole is visible a crown rump measurement is made, which correlates closely to gestational age
What is anencephaly?
Neural tube defect - vault of the skull doesn’t develop and brain matter is unprotected from the environment and becomes worn away
How is anencephaly identified?
Normal fetal skull can’t be seen on ultrasound, usually first trimester
At what weeks gestation can combined ultrasound and biochemical screening take place?
11-14
What invasive confirmatory investigation can be done if screening tests for Down’s come back positive?
Invasive test - amniocentesis
What screening test can be done for down’s after 14 weeks?
Second trimester screening: Serum alphafetoprotein Serum Total human chorionic gonadotrophin Serum unconjugated eostriol Serum inhibin-A
What is the detection rate in second trimester down’s screening?
75%
What is the detection rate of combined ultrasound and biochemical screening?
85% - 5% false positive rate
What is used to assess risk of neural tube defect?
Alphafetoprotein at 15-20 weeks
Ultrasound - preferred test
What is the most common neural tube defect?
Spina bifida
What is the purpose of the second trimester ultrasound?
Identify structural abnormalities - almost all abnormalities that can be seen on USS can be seen by week 20
What organ systems should be assessed in the second trimester USS?
Central nervous system Genitourinary tract Gastrointestinal tract Musculoskeletal system Cardiovascular - heart
What effects can neural tube defects have on the skull shape?
Frontal bossing
Lemon shape
What abnormalities can be seen in second trimester USS?
Cystic hygroma Diaphragmatic hernia Duodenal atrasia Dilated renal pelvises Exomphalos/gastroschisis
What is the purpose of third trimester USS?
Assess fetal wellbeing
How is diaphragmatic hernia diagnosed?
Abdominal organs found within chest
What sign is indicative of duodenal atresia?
Double bubble at level of stomach
What is elevated alphafetoprotein a sign of other than neural tube defects?
Incorrect gestational age Multiple pregnancy Bleeding in pregnancy Fetal death Abdominal wall abnormalities
