Antenatal Care Flashcards
INTRAUTERINE PREGNANCY
definition
An intrauterine pregnancy (IUP) occurs when a fertilised egg implants and starts to develop within the uterus there is the presence of a gestational sac that contains either a yolk sac or a foetal pole
INTRAUTERINE PREGNANCY
How investigations can be used to diagnose pregnancy?
Ultrasonography - dating scan at 8-14 weeks
serum B-hcg
progesterone
early pregnancy factor
DIAGNOSING INTRAUTERINE PREGNANCY For the following times since last menstrual period give the expected HCG levels and landmarks seen on ultrasonography 1. 4 weeks 2. 5 weeks 3. 6 weeks
- gestational sac / 10 to 708 mIU/mL
- yolk sac / 18–7,340 mIU/mL
- foetal pole and cardiac activity / 1,080–56,500 mIU/mL
DIAGNOSING INTRAUTERINE PREGNANCY
What are the main symptoms/information that should be gained from history?
- menstrual history (pattern, date, onset of last menses, duration, flow, frequency). Atypical last menstrual period, contraceptive use, history of irregular menses can confuse diagnosis of early pregnancy and up to 25% of women bleed during first trimester
- Nausea and vomiting (common in 1st trimester, occur any time of day, can persist through pregnancy)
- Frequency of micturition (increased plasma volume and urine production, pressure effect of uterus on bladder)
- Excessive lassitude or fatigue (common in early pregnancy and disappears after 12 weeks)
- Breast tenderness (especially seen in month after first period is missed)
- Foetal movements (20 weeks in nullipara, 18 weeks in multipara)
- pica (abnormal desire to eat something not regarded as nutritive eg dirt)
DIAGNOSING INTRAUTERINE PREGNANCY
describe the classical presentation of pregnancy?
woman with regular, frequent menses who present with amenorrhea, nausea, vomiting, generalised malaise and breast tenderness
DIAGNOSING INTRAUTERINE PREGNANCY
what are the important examination findings?
- enlarged uterus after bimanual examination
- breast changes
- softening and enlargement of cervix (Hegar sign at 6 weeks).
- Chadwick sign: bluish discolouration of cervix from venous congestion observed by 8-10 weeks
- After 12 weeks uterus is palpable abdominally and fetal heart may be heard using hand held doppler
DIAGNOSING INTRAUTERINE PREGNANCY
- what secretes HCG?
- when does HCG peak?
- how can HCG be measured?
- hCG secreted by trophoblastic tissue
- 8-12 weeks - increasing levels of hCG exponentially from 8 days after ovulation and doubles every second day
- hCG can be measured in blood or urine
DIAGNOSING INTRAUTERINE PREGNANCY
what is the role of testing progesterone in early pregnancy?
- Useful for evaluation of abnormal early pregnancy
- Reflects progesterone production of corpus luteum
- Viable intrauterine pregnancy diagnosed with high sensitivity if serum greater than 25ng/mL (low levels can help diagnosis of nonviable pregnancy)
DIAGNOSING INTRAUTERINE PREGNANCY
what is the role of testing for early pregnancy factor?
- Detectable in serum 36-48 hours after fertilisation, peaking early in first trimester
- Undetectable in ectopic pregnancies, spontaneous abortions
DIAGNOSING MULTIPLE PREGNANCY
What investigations are valuable in diagnosing multiple pregnancy?
- hCG levels: quite high with multiple pregnancy
- alpha fetoprotein: protein released by fetal liver, found in mothers blood may be high when more than 1 foetus making the protein
- ultrasound: using vaginal transducer especially in early pregnancy or abdominal transducer later in pregnancy
ULTRASONOGRAPHY
what can be assessed by ultrasound in the first trimester?
- Accurate dating by measuring CRL (crown rump length) at 8-12 weeks
- Identify embryo and yolk sac
- Foetal number (number of amniotic sacs and chorionic sacs)
- Assess anatomy
- Evaluate maternal uterus, tubes, ovaries and surrounding structures
- Evaluate foetal nuchal fold
ULTRASONOGRAPHY
What can be assessed by ultrasound in the second and third trimester?
- Foetal number (number of amniotic sacs and chorionic sacs)
- Foetal cardiac activity
- Foetal position relative to uterus and cervix
- Location and appearance of placenta, umbilical cord
- Amniotic fluid volume
- Gestational age
- Foetal weight estimation
- Foetal anatomical survey
- Evaluate maternal uterus, ovaries and surrounding structures
ULTRASONOGRAPHY
How can ultrasound be used for dating and growth monitoring?
- ultrasound offers alternative to estimating gestational age, most accurately using crown rump length between 7 and 13 weeks
- after 13 weeks foetal age estimated using biparietal diameter, head circumference, femur length, crown heel length and other parameters
- dating more accurate when done earlier in pregnancy
ULTRASONOGRAPHY
How can ultrasound be used for sex discernment?
- from early as 11 weeks but only accurate after 13 weeks
- accuracy depends on gestational age, precision of sonographic machine, expertise of operator, foetal posture
ULTRASONOGRAPHY
why is it important to assess cervix on ultrasound?
- useful to assess in women at risk of premature birth
- short cervix associated with higher risk for premature delivery
ULTRASONOGRAPHY
What is the purpose of abnormality screen?
- detect defects before birth eg checking status of limbs and organs
- nuchal translucency thickness
- foetal organ anomaly done around weeks 18-23
what is the aim of antenatal care?
- provide evidence based information and support to women and their partners to make informed decisions about care
- advice on minor problems and symptoms of pregnancy
- facilitate provision of prenatal screening and management of abnormalities
- monitor foetal and maternal well being and screen for commonly occuring complications (BP, urine for pre-eclampsia and diabetes)
- determine timing and mode of delivery when complications arise or if pregnancy continues after due date
- develop partnership between woman and health professional
- increase understanding of public health issues
- provide opportunities to prepare for birth and parenthood
what publications influence antenatal care provision?
- MBRRACE-UK (mothers and babies-reducing risk through audits and confidential enquiries across the UK)
- NICE antenatal care guideline
- Evidence based practice
- Local policy/guidelines for practice
- Midwifery 2020
what was the purpose of national maternity review ‘better births’?
Personalised care, continuity of care, safer care, better postnatal and perinatal mental health care, multi-professional working, working across boundaries fairer payment system
what are the different aspects of antenatal care?
- Booking
- Regular visits
- Parentcraft education
- At every interaction a holistic approach should be used to consider physical, psychological, social and spiritual dimensions
ANTENATAL CARE
Describe the booking interview?
- NICE recommends booking appointment is done by 10 weeks
- Important opportunity to begin the relationship with the woman
- Opportunity to discuss concerns
- Detailed history and discussion of screening tests takes place
- Baseline recordings taken
- Public health advice given
ANTENATAL CARE
What information is gained in the booking interview?
- Demographic details
- Present pregnancy and menstrual history
- Previous pregnancies
- Medical history
- Surgical history
- Social and lifestyle history
- Family history
- Baseline observations
ANTENATAL CARE
how many antenatal visits will these women attend?
1. parous women
2. nulliparous
- 7
2. 10
ANTENATAL CARE
- when are the scheduled antenatal visits?
- which of these are for nulliparous women only?
- booking, 16, 25, 28, 31, 34, 36, 38, 40, 41 weeks
2. 25, 31, 40
ANTENATAL CARE
what routine blood tests are performed in pregnancy?
- FBC (anaemia)
- Blood grouping and antibody screen (identify rhesus -ve women at risk of rhesus isoimmunisation and detect abnormal antibodies)
- Rubella screen (2% nulliparous, 1% multiparous women are not immune and require post partum vaccination)
- Syphilis screen (treat to prevent congenital syphilis)
- Hepatitis B screen (at booking so effective postnatal intervention can be offered, 90% of neonates become chronic carriers and risk post infective hepatic cirrhosis and hepatocellular carcinoma)
- HIV screen (universal at booking in visit in order to reduce vertical transmission by antiretrovirals)
- Haemoglobin electrophoresis (routine in women of minority ethnic or racial origins with high incidence of haemoglobinopathies (cyprus, eastern Mediterranean, middle east, Indian subcontinent, south east asia))
- Others (thyroid function tests, HbA1c, baseline urea and creatinine)
ANTENATAL CARE
what is the purpose of the visit at 8-12 weeks (ideally <10 weeks)?
booking
information - diet, alcohol, smoking, folic acid, vit D, antenatal classes
BP
urine dip
BMI
bloods- FBC, group, rhesus, red cell autoantibodies, haemoglobinopathies, hep B, syphilis, HIV
urine culture
ANTENATAL CARE
what is the purpose of visit at 10-13+6 weeks?
early scan to confirm dates, exclude multiple pregnancy
ANTENATAL CARE
what is the purpose of the visit at 11-13+6 weeks?
Downs syndrome screening (nuchal test)
ANTENATAL CARE
what is the purpose of visit at 16 weeks?
information on anomaly and blood results
if Hb <11g/dl consider iron
routine care - BP and urine dipstick
ANTENATAL CARE
what is the purpose of visit at 18-20+6 weeks?
anomaly scan
ANTENATAL CARE
what is the purpose of visit at 25 weeks?
only if primip routine care BP urine dip symphysis-fundal height
ANTENATAL CARE
what is the purpose of visit at 28 weeks?
routine - BP, urine dip, symphysis-fundal height
second screen for anaemia and atypical red cell alloantibodies
if iron <10.5g/dl consider iron
1st dose anti-D prophylaxis to rhesus -ve women
ANTENATAL CARE
what is the purpose of visit at 31 weeks?
routine care
only if primip
ANTENATAL CARE
what is the purpose of visit at 34 weeks?
routine care
2nd dose anti D prophylaxis to rhesus -ve women
information on labour and birth plan
ANTENATAL CARE
what is the purpose of visit at 36 weeks?
routine care
check presentation- external cephalic version
information on breast feeding, vit K, baby blues
ANTENATAL CARE
what is the purpose of visit at 38 weeks?
routine care
ANTENATAL CARE
what is the purpose of visit at 40 weeks?
only if primip
discuss options for prolonged pregnancy
ANTENATAL CARE
what is the purpose of visit at 41 weeks?
routine care
discuss labour plans and possible induction
ANTENATAL CARE
describe the use of menstrual history in determining gestational age?
- The first day of the last menstrual period used to calculate gestational age and EDD
- This may be inaccurate (women not certain of day of period, ovulation not always on day 14 and proliferative phase may be shorter or longer
- EDD can be calculated using Naegele’s formula
- 40% of women deliver within 5 days of EDD and 2/3 within 10
- 11-42% of gestational age estimates from this may be inaccurate
- Day of embryo transfer used in IVF
ANTENATAL CARE
describe the role of ultrasound scanning in determining gestational age?
- Between 8 and 13 weeks
- Most accurate measure of gestational age and should be used to calculate EDD
- Unreliable before 8 weeks
- After 13 weeks other factors may affect foetal growth so estimate should be made using BPD and femur length (this may be unreliable)
ANTENATAL CARE
describe what is meant by crown rump length?
- Used between weeks 8-13
- Measured from one foetal pole to the other along its longitudinal axis in a straight line
ANTENATAL CARE
describe the principles of screening in pregnancy?
Ideally screening should be offered to all women at time of booking. Detailed, unbiased, written information provided about conditions being screened for, types of tests and implications of results. Important to explain that a negative result does not guarantee that the baby does not have that or another abnormality
ANTENATAL CARE
why is prenatal diagnosis important?
- Enabling decision on timing, mode, and place of delivery (e.g. in a unit that provides paediatric surgery).
- Preparing parents to cope with an affected child.
- Introducing parents to specialist neonatal services.
- Ensuring fetal surveillance, such as later USSs to monitor the condition and ensure the best possible outcome.
- Potentially allowing in utero treatment (rarely available at present).
- Giving parents the option of terminating the pregnancy in severe cases.
ANTENATAL CARE
describe counselling?
- How parents respond to the news that there is abnormality with foetus will vary with factors such as age, social background, and religious belief.
- Not all parents will wish to terminate the pregnancy: even in the face of abnormalities incompatible with life.
- Some parents report that the opportunity to hold their child enabled them to grieve.
- Counselling must be supportive, informative, and non-directional.
- Care must also be taken to counsel adequately before any screening tests.
- If parents have no intention of having the riskier diagnostic tests performed then there is little benefit in screening and much anxiety may be generated.
ANTENATAL CARE
describe what makes a good screening test?
- Should be cheap and widely available.
- Non-invasive, safe, and acceptable.
- Have good sensitivity (high detection rate) and specificity (low FPR).
- Provide a measure of the risk of being affected by a certain disorder
- Must have a suitable diagnostic test for those identified as ‘high risk’.
ANTENATAL CARE
what makes a good diagnostic test?
- Need to definitely confirm or reject the suspected diagnosis (e.g. the fetus does, or does not, have Down’s syndrome).
- Must be as safe as possible.
- Must have high sensitivity and specificity.
- The implications of the disorder tested for must be serious enough to warrant an invasive test.
ANTENATAL CARE
what is the combined test?
- Screening test for Down’s syndrome, Edwards’ syndrome and Patau’s syndrome
- 10-14 weeks
- Combines ultrasound with blood test
- Carried out at same time as dating scan
- Nuchal translucency: Risk similar to triple test but can pick up foetuses with other trisomies or congenital heart disease. This is done at an earlier stage so those at high risk may be offered chorionic villus sampling
- Blood tests measure hCG and PAPP-A
- Alternatives to combined test: if nuchal translucency not possible or more than 14 weeks then quadruple blood screening which only screens for downs. A mid pregnancy scan can screen for Edwards’ and Patau’s syndrome for those too far into pregnancy for combined test.
ANTENATAL CARE
what is the role of serum alpha fetoprotein?
- Neural tube defects account for 50% of congenital abnormalities
- Some hospitals offer blood test at 15-17 weeks to measure serum alpha fetoprotein
- Majority of these defects detected by ultrasound at 18-20 weeks
