screening and chronic conditions Flashcards
- what is meant by gestational age?
- conception?
- G and P
- trimesters?
Gestational age = age of fetus calculated from the first** **day of the LMP
Conception = 2 weeks after 1st day of LMP with a regular 28 day cycle
- Gravida (G) : is how many pregnancies she’s had
- Para (P): # of times the woman has given birth AFTER 24 wks gest, regardless of whether the fetus was alive or stillborn
Trimesters:
o First – 1-12 wks
o Second – 13-27 wks
o Third – 28 – 40 wks
how do u access gestational age?
DATING SCAN - Should be offered an early USS between 10+0 & 13+6 to determine gestational age + to detect multiple pregnancies
- Crown-rump length measurement should be used to determine gestational age
- If CRL>84, age should be estimated using head circumference*
- First trimester USS MOST ACCURATE way to confirm gestational age in pregnancy!!!!!!
§ LMP - The accuracy of using LMP to date pregnancy is dependent on having regular cycles and assuming ovulation/conception on day 14 of the cycle, and the woman accurately remembering the date of their LMP
- Fundal height : correlates with gestational age from 24 weeks
o Fundus just above pubic symphysis = 12 weeks
o Level of umbillicus = 20 weeks
o Pubic symphysis to fundus = gestational age after 24 weeks
Antenatal care: lifestyle considerations
advice on supplements to take, things to avoid, sex, excersize
folic acid 400mcg b4 pregnancy to 3 mnths (reduces neural tube defects)
TAKE vit D (10 mcg or 400 IU daily)
AVOID vit A and eating liver or pate (vitamin A is teratogenic at high doses)
Don’t drink alcohol (risk of fetal alcohol syndrome)
Don’t smoke
Avoid unpasteurised dairy or blue cheese (risk of listeriosis)
Avoid undercooked or raw poultry (risk of salmonella)
Continue moderate exercise but avoid contact sports
Sex is safe
Flying increases the risk of (VTE)
Place car seatbelts above and below the bump (not across it)
Clinical exam. & risk assessment in antenatal Care
what is the point of doing a risk assessment?
- Measure height, weight and BMI
- domestic violence
Risk assessment determines whether they need to see an obstetrician or a mid-wife/GP for their antenatal appt.
- Screening for gestational diabetes risk factors
- Screening for pre-eclampsia risk factors
- Identify FGM
- Assess mental illness/depression risk
how many antenatal visitis are there?
10 antenatal visits in the 1st pregnancy if uncomplicated
7 antenatal visits in subsequent pregnancies if uncomplicated
At the booking clinic, those women who choose to have screening, what tests should be arranged? (4)
Blood tests (to check blood group and rhesus D status, screening for haemoglobinopathies, anaemia, red-cell alloantibodies, hepatitis B virus, HIV and syphilis), ideally before 10 weeks
urine tests (to check for proteinuria)
USS to determine gestational age using:
- crown–rump measurement between 10 weeks and 13 weeks 6 days
- head circumference if crown–rump length is above 84 millimetres
Down’s syndrome screening using:
things discussed at the booking clinic? (b4 10 wks)
things dicussed?
- What to expect at different stages of pregnancy?
- Lifestyle advice in pregnancy (e.g. not smoking)
- Supplements (e.g. folic acid and vitamin D)
- Plans for birth
- Screening tests (e.g. Downs screening)
- Antenatal classes
- Breastfeeding classes
- Discuss mental health
Estimated date of delivery (EDD) calculation?
· Estimated using Naegele’s rule
first day of LMP + 7 days + 1 year – 3 months
§ Inaccurate if
· Date of LMP uncertain or unknown
· Patient has irregular menstrual cycles
· Patient conceived while taking the contraceptive pill
when and how do u screen for Down’s syndrome?
ALL women are offered screening for DS
11 - 14 weeks
The purpose of the screening is to decide which women should receive more invasive tests to get a definitive diagnosis.
COMBINED TESTING –> _first line (_USS and bloods)
- Women’s age
- USS thick Nuchal translucency >6mm
- ↑ serum B-HCG
- ↓ pregnancy associated plasma protein A (PAPP-A)
PAPPA is a glycoprotein produced by the placenta , low levels reflect poor early placentation.
what tests would you do if they booked late for the Downs syndrome screening?
(btw 15 - 20 weeks)
©© Triple Test (only involves maternal Blood tests)
- Beta-HCG
- LOW Alpha-fetoprotein (AFP)
- LOW Serum oestriol
©© Quadruple Test
same as above but + maternal blood testing for INHIBIN-A (high)
AFP is a glycoprotein made by fetal liver and GI tract. unlike DS where its low, if high AFP there is a fetal malformation ex : Turner’s syndrome
if screening suggests an increased risk of aneuploidy, and risk score of DS 1 in 150, what can you do?
woman offered amniocentesis or chorionic villus sampling.
takes sample of the fetal cells & perform karyotyping
- Chorionic villus sampling (CVS) USS guided biopsy of the placental tissue. This is used when testing is done earlier in pregnancy (before 15 weeks).
- Amniocentesis USS guided aspiration of AF using a needle & syringe. Done later in pregnancy bc theres enough AF to make it safer to take a sample.
Anti-D PROPHYLAXIS should be offered AFTER the procedure if mother is RhD -ve
Anomaly scan
what is it?
when is it done?
is a detailed US undertaken at 18–22 wks to detect structural malformations.
Screening for
- T13 (Patau syndrome)
- T18 (Edwards syndrome)
- T21 (Downs syndrome)
Additional care for high BMI women?
what week is the uterus palpable?
what causes might there be for a “larger-for-date uterus”?
12 weeks
incorrect dating
fibroids
multiple gestation
molar pregnancy
what 11 conditions are screened for at the 20 week scan?
aanencephalopathy
open spina bifida
cleft lip
diaphragmatic hernia
gastroschiais
exompthalmus
