Antenatal screening Flashcards
Pre-pregnancy counselling looks at a women’s background and health to ensure a safe pregnancy. What sorts of things are assessed in all pregnant women?
- General health measures - Improve diet, Optimise BMI and Reduce alcohol consumption
- Smoking cessation
- Folic acid - 400 mcg and 5mg
- Up to date cervical smear
How does obesity affect pregnancy?
- Higher rate of poor outcomes including miscarriage and still birth.
- It also affects the function of the uterus in labour.
- Venous thromboembolic events (DVT and PE) are more common in obese patients.
- And routine measurements of fundal height to monitor foetal growth and presentation may be impossible on abdominal palpation.
Substance misuse effect on unborn foetus
- Heroin, methadone and benziodiazapines are addictive to the fetus and cause withdrawal syndrome in the baby when it is cut off from its supply at birth.
- Cocaine/crack cocaine are associated with placental abruption resulting in foetal death.
What is done for pregnant women with known medical problems?
- Optimise maternal health e.g have diabetes under control
- Stop/change any unsuitable drugs - Good examples are chronic hypertension and epilepsy - Avoid ACE-I and sodium valproate
- Advise regarding complications associated with maternal medical problems e.g worsening of maternal disease due to pregnancy or associated foetal abnormalities
- Occasionally advise against pregnancy e.g significant cardiac disease (maternal mortality risk)
What are some serious problems that women can develop during pregnancy? (4)
- Pre-eclampsia
- Gestational diabetes
- DVT
- PE
C sections in pregnancy
- Usually if a woman has only had one c-section for a non-recurring cause such as breech presentation she will be fine to undertake a trial of labour.
- However, after 2 previous caesareans it is customary to deliver by elective caesarean again.
What does antenatal care for the mother include?
- Check for raised BP
- Urinalysis
- Mental health
- Birth planning
- Carbon monoxide testing
Aims of antenatal care (3)
- Reduce foetal and maternal mortality
- Aims to identify problems during pregnancy
- Address concerns and prepare for parenthood
What does antenatal care for the foetus include?
- Screening
- Identifying reduced foetal movements
- Identify malpresentation - small for gestational age? Abnormalities?
Social aspects of antenatal care
- Support - social services, midwife, GP etc
- Domestic violence
- Psychiatric illness
- Counselling
What does an antenatal examination involve? (3)
- Abdominal palpation
- Determine foetal presentation
- Listen to foetal heart
What are you looking for when examining the abdomen of a pregnant woman?
- Assess fundal height (SFH) - measured from the top of the mother’s uterus to the top of the mother’s pubic symphysis
- Estimate size of baby
- Estimate liquor (amniotic fluid) volume
If a women accepts offer of screening what must be offered prior to this?
Counselling - in order to help deal with a the result
Which infections are routinely screened for during the 1st trimester?
- Rubella
- HIV
- Hep B
- Syphilis
- Sickle cell disease
- Thalassaemia - inherited blood conditions where haemoglobin is abnormal.
Congenital rubella infection in a pregnant woman can cause what birth defects in their baby?
- Learning disabilities
- Blindness
- Deafness
- Heart defects
What is screened for during the 1st trimester and again at 28 weeks?
- Anaemia - iron deficiency
- Isoimmunisation i.e rhesus D disease, red cell antibodies (can cause anaemia in the foetus) or anti-c and anti-k too
Why is it important to screen for anaemia?
- Additional iron is required to make extra maternal red blood cells as normal adaptation of pregnancy and needed by the developing fetus and placenta.
- If her iron stores are low prior to pregnancy she may well become iron deficient during pregnancy.
- Once detected this can be remedied by taking iron tablets.
What is isoimmunisation?
A condition that happens when proteins on the surface of the baby’s red blood cells are different from the mother’s protein and are incompatible, causing her immune system to react and destroy the baby’s red blood cells (RBC destruction causes anaemia in the foetus)
There are a number of types of isoimmunisation but which is the most common?
Rhesus disease ( RhD)
What type of antibodies are produced against Rhesus disease?
anti-D antibodies
What do you look for in a first visit scan (between 11-14 weeks)?
- Is there a viable pregnancy?
- Is there one foetus or is it a multiple pregnancy?
- Identify abnormalities incompatible with life
- Nuchal translucency for Down’s syndrome
Screening for Chromosomal Abnormalities
Women and their partners must be aware prior to any screening taking place that tests for fetal abnormality only provide a risk of their baby being affected. Further testing will be offered to definitively tell if a baby is affected
What are the important factors in maternal history when assessing the risk of Down’s Syndrome? (2)
- Maternal age - the incidence of Down syndrome increases with advancing maternal age
- Family history
What does screening for down’s syndrome entail?
- CUB (combined ultrasound/biochemical) screening (blood test
- Nuchal translucency is measured via USS- fluid under the skin at the back of the baby’s neck
- Serum beta-human chorionic gonadotrophin (beta-hCG) - significantly elevated at 11–14 wks gestation in Down’s syndrome pregnancies
- Pregnancy associated plasma protein A (PAPP-A) - decreased in down’s
Sometimes a Nuchal translucency measurement is not possible during the first scan due to foetal position or maternal BMI. What is the alternative option?
Second trimester biochemical screening
- Looks at hCG, alpha-fetoprotein, inhibitin-A etc
What further tests can you do if you think there is a high risk of down’s or another genetic/ chromosomal condition? (3)
- Chorionic villus sampling
- Amniocentesis
- Non-invasive prenatal testing
What is non-invasive prenatal testing?
- Maternal blood is taken
- From that you can detect foetal cell free DNA and look for chromosomal trisomies
- Now offered in high risk cases
Which hormones are screened for in the 2nd trimester?
- Alpha-fetoprotein
- hCG
- Estriol
- Inhibin-A
- Oestradio
Which condition cannot be detected on the detailed structural anomaly scan?
- A. Cleft lip
- B. Autism
- C. Talipes (club foot)
- D. Hypoplastic left heart syndrome
b. Autism
What is Ramipril and why is it not recommended for use during pregnancy?
ACE inhibitor
It has been shown that use of ramipril during the 2nd and 3rd trimesters of pregnancy harms the unborn baby’s kidneys and even increases the risk of death to the unborn baby
What sign represents Dichorionic pregnancies?
Lambda sign
In order to prevent Rhesus disease in the baby, which women are recommended to receive anti-D antibodies during pregnancy?
All rhesus negative women
Rhesus disease
