Antenatal Care and Screening Flashcards
Pre-pregnancy Counselling is for who?
Ideally for all women
In Scotland, a third of pregnancies are unplanned
In an ideal world all women would receive some pre-pregnancy counselling in reality the majority of pregnancies are unplanned but pre-preg. Counselling is vital for women with any previous health or pregnancy problems
Pre-pregnancy Counselling – All women.
This can be done in primary care
General health measures - Improve diet, Optimise BMI, Reduce alcohol consumption
Smoking cessation advice
Folic acid - 400 mcg, 5mg
Up to date cervical smear
All features of a woman’s background can affect the outcome of her pregnancy.
how does obesity effect pregnancy?
Obesity has a detrimental affect on pregnancy with a higher rate of poor outcomes including miscarriage and still birth. It also affects the function of the uterus in labour. Routine measurements of fundal height to monitor fetal growth and presentation may be impossible on abdominal palpation. Venous thromboembolic events are more common in obese patients
how does lacohol affect pregnancy?
Alcohol is associated with fetal abnormalities causing a fetal alcohol syndrome which produces a typical facial appearance and affects learning, the routine advice given to pregnant women is to avoid alcohol although there is no evidence of harm from minimal alcohol consumption during pregnancy
what should be done in a risk assessment of someone pregnant?
Age - Pregnancy outcomes are poorer at both ends of the fertile population. Teenagers may be socially deprived with lack of support, smoke more, and not receive the antenatal care they need, often booking late. Older women, particularly the over 40s, are more prone to pre-existing medical conditions and develop complications of pregnancy such as gestational diabetes and hypertension. Chromosomal disorders increase dramatically with advancing maternal age.
Parity - Pre-eclampsia is predominantly a condition of nulliparity, occurring in the first pregnancy. Grand multiparity (4 or more deliveries) predisposes women to postpartum haemorrhage.
Occupation - A patient’s occupation may expose them to situations that put either themselves or their fetus at risk. They may have a very busy job with inadequate rest periods or be exposed to substances such as chemicals which cause fetal anomalies.
Substance misuse - Substance misuse such has effects both on the mother who may not seek antenatal care or attend intermittently and on the fetus. Heroin, methadone and benziodiazapines are addictive to the fetus and cause a withdrawal syndrome in the baby when it is cut off from its supply at birth. Cocaine and crack are associated with abruption resulting in fetal death. Women with substance misuse are seen in a specialist multidisciplinary clinic involving obstetricians, midwives, members of the substance misuse team (psychiatrists & CPNs), social workers and health visitors.
Pre-pregnancy Counselling:
what should be done about known medical problems?
Optimise maternal health - Eg Diabetes, Pregnancy is advised against when the HbA1c is significantly elevated
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 - Worsening of maternal disease due to pregnancy, Associated fetal abnormalities
Occasionally advise against pregnancy - Significant cardiac disease can be associated with maternal mortality, Can only advise
Don’t forget that women can also get other _________ in pregnancy eg cancer
Psychiatric health is important
illnesses
Pre-pregnancy Counselling - previous pregnancy problems
Understanding the past pregnancy helps guide any treatment or investigations needed in a subsequent pregnancy
what needs ot be thought about?
If a woman has had a pregnancy before this may indicate how she may progress in the current pregnancy. If there were complications the woman as well as the obstetrician is likely to be anxious.
If a patient previously had a caesarean section it is necessary to determine the safest mode of delivery on this occasion. Usually if she has only had one caesarean 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.
Maternal - Pre-eclampsia, Gestational diabetes, Previous caesarean section, DVT or PE
Fetal - Intrauterine growth restriction, Preterm birth
High quality antenatal care reduces fetal and maternal mortality
Aims to identify problems during pregnancy
Address concerns and prepare for parenthood
what needs to be done and what problems may there be?
- Mother – raised BP, urinalysis, mental health, birth planning, Problems such as pre-exisiting or developing illness, ‘minor’ problems of pregnancy such as anaemia
- Fetus – screening, reduced fetal movements, malpresentation, Small for gestational age, Fetal abnormality
- Social – CO testing, Support, Domestic violence, Psychiatric Illness
Antenatal Examination - what is done in abdominal palpation?
Assess symphyseal fundal height (SFH)
Estimate size of baby
Estimate liquor volume
If fetal lie is abnormal has implications for delivery
Some abnormal lies are secondary to problems such as placenta praevia which can have serious consequences around he time of delivery and are important to detect
Antenatal Examination - detemrine fetal presentation
what are the different ones?
Listen to the fetal heart
If the baby remains in a breech presentation after 36 weeks it is normal to offer ECV.
If this is declined or fails the baby will usually be delivered by elective caesarean section as there is good evidence that this is safer for the baby
Antenatal Screening - is it compulsory and what does it allow?
Women are offered screening but this is not compulsory
Appropriate counselling prior to screening is important
Allows conditions to be detected early in a symptomless population to be treated for mother/baby
Screening is the testing of a symptomless population in order to detect cases of a disease at an early stage and a variety of screening tests are offered to pregnant women
Screening for Infection – carried out in 1st trimester
what are they? and the treatment?
Hepatitis B - If infected can provide passive and active immunisation for baby
Syphilis - Easily treated with Penicillin
HIV - Maternal treatment and careful planning reduces vertical transmission
MSSU - Urinary tract infection
All pregnant women are screened for Rubella, Hepatitis B, Syphilis, and HIV as part of routine ANC. Consent is required for all testing
Screening for anaemia and isoimmunisation – when is it done?
performed in 1st trimester and at 28 weeks
Iron deficiency anaemia
Screening for anaemia and isoimmunisation – performed in 1st trimester and at 28 weeks
what isoimmunisation?
High levels of certain red cell antibodies can cause anaemia in the fetus
Rhesus D negative women are offered Anti-D at 28 weeks gestation and following any sensitising event (eg, vaginal bleeding or amniocentesis) to reduce risk of transplacental passage of antibodies
Anti-c, Anti-K
Other red cell antibodies can be present but do not affect the fetus
Screening for anomalies by ultrasound:
what is done on your first visit scan?
Ensure pregnancy viable
Multiple pregnancy
Identify abnormalities incompatible with life
Offer and carry out Down’s syndrome screening
Ideally performed between 11 and 14 weeks gestation
Screening for Chromosomal Abnormalities
how is it done?
Multiple screening tests are available
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
Embarking on prenatal screening may sometimes result in parents having to make a difficult decision regarding termination of pregnancy
Screening For Down Syndrome - what is the risk of downs syndrome?
Down Syndrome is a chromosomal abnormality characterised by 3 copies of chromosome 21
Overall risk is 1 in 700
Usual cut off for ‘high risk’ reporting is 1 in 150
Maternal age
- 1in 1667 risk at age 20yrs
- 1 in 30 risk at age 45yrs
Personal or family history of chromosomal abnormality
how does age and family history affect the risk of downs syndrome?
Important factors in the maternal history when assessing the risk of Downs syndrome are maternal age as the incidence of Downs increases with advancing maternal age and Family history which may indicate a balances translocation in some members of a family.
First Trimester Screening - when does it occur?
Carried out at 10-14 weeks gestation
First Trimester Screening - what is it used for?
Uses maternal risk factors, serum b-human chorionic gonadotrophin (b-hCG) and pregnancy associated plasma protein A (PAPP-A) and fetal nuchal translucency (NT) measurement
Detection rate for Trisomy 21 (downs) of ~90%, invasive testing rate of 5% (polysomy in which there are three instances of a particular chromosome, instead of the normal two)
what is Nuchal Translucency?
NT measurements are taken between Crown Rump Length’s of 45-84mm
Nuchal translucency (NT) is the sonographic appearance of a collection of fluid under the skin behind the fetal neck in the first-trimester of pregnancy
Second Trimester Screening
Sometime NT measurement is not possible due to fetal position or maternal BMI
what is an Alternative option?
second trimester biochemical screening
hCG, unconjugated oestrodiol, alpha-fetoprotein, inhibin-A
14+2 – 20+0 weeks gestation
If Alpha-fetoprotein >2.0 MoM, can raise concerns about fetal abnormality (eg spinabifida or exomphalos)
What happens with a high risk result?
Further testing is offered if risk is >1 in 150
what options ofr further testing are avalible for high risk results?
Options:
- CVS
- Amniocentesis
- Non-invasive Prenatal testing
what is CVS, when is it done, and what are the risks?
It involves removing and testing a small sample of cells from the placenta, the organ linking the mother’s blood supply with her unborn baby’s.
Between 10-14 weeks
1-2% risk of miscarriage
what is amnciocentesis, when is it done and what are the risks?
It involves removing and testing a small sample of cells from amniotic fluid, the fluid that surrounds the unborn baby in the womb (uterus).
15 weeks onwards
~1% risk of miscarriage
how is non-invasive prenatal testing carried out?
Maternal blood taken
Can detect fetal cell free DNA
Can look for chromosomal trisomies
Not currently offered on NHS but parents can have test privately
If high risk, still recommended to have invasive testing to confirm
What Changes to Scottish screening policy as of 28th September 2020 occured?
1st trimester screening will include testing for Trisomy 13 and Trisomy 18
NIPT will be available for high risk results
what is the use of the second trimester ultrasound?
Second Trimester ultrasound is performed with the purpose of detecting fetal abnormality
This is a good screening test for major structural abnormalities but a poor test for chromosomal abnormalities as:
- 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
Summary:
Pre-pregnancy counselling is desirable for all women but essential for women with any increased risk of __________
Although pregnancy is not an illness, high quality antenatal care reduces maternal and fetal ________ and _______
complication
morbidity
mortality
Summary:
Various _________ are available for testing pregnancies for fetal abnormality
The _________ of a ‘screening test’ must be clear to women at the outset
Screening for fetal abnormality comprises:
- Features in _______
- _________
- Maternal serum __________
investigations
limitations
history
Ultrasound
biochemistry
