antenatal care Flashcards
how might a woman with pulmonary hypertension have a child?
surrogacy
what ix should a GP order in a woman who is planning on becoming pregnant?
rubella ab, varicella ab, pap smear (any abnormal cells, treated BEFORE pregnancy)
blood group and rhesus/kell antibody status
what is the most accurate way of dating gestational age?
ultrasound, generally the first trimester u/s
How might we confirm pregnancy?
Hx: missed period, urinary frequency, nausea, breast tenderness
Ex: uterine enlargement?
Ix: Serum BHCG (100% reliable) or Urinary HCG (cross reacts with LH, but false positives and false negative)
you order MCV for a women in first antenatal visit. what are you worried about?
thalassemia
test for thalassemia minor in the partner
2 x thalassaemia minor
1/4 chance thal major in child
what is the most teratogenic epileptic drug?
sodium valproate
when should a mother begin to detect fetal movements?
after 20 weeks
What are some pre-pregnancy behavioural advice you can give a woman who wishes to become pregnant?
behavioural advice–> avoid teratogens,
folate 500mcg for three months to prevent neural tube defects–> up to 6 weeks post conception
(5mg folate for FMH of neural tube defects, anticonvulsants, diabetes)
Vitamin D, iodine, iron
Avoid smoking, alcohol etc drugs, social history,
Pap smear up to date?
Serology (rubella/varicella)–> check immune status and if not immune administer vaccination and wait 3 months prior to pregnancy
Recommend intercourse every 48hrs in the week leading up to ovulation (mid-cycle) 5 days before and 5 days after ovulation have sex every 2nd day
Hand hygiene/listeria
how might we confirm pregnancy?
Hx: missed period, urinary frequency, nausea, breast tenderness
Ex: uterine enlargement?
Ix: Serum BHCG (100% reliable) or Urinary HCG (cross reacts with LH, but false positives and false negative)
for what medical conditions should we advise AGAINST getting pregnant?
Prognostic advice:
renal insufficiency (Creatinine >0.3 = bad outcome)
pulmonary hypertension (–> heart failure, 50% mortality)
what medical conditions should we screen for in subsequent antenatal visits?
Preeclampsia- HT, proteinuria and oedema
Placental insufficiency (poor fetal movements and poor growth around 19 wks)
what ix do we do at 28 and 36 weeks gestation?
28 weeks= FBE, OGTT, +/- Rh ab level and anti D administration if Rh Neg (15% of women)
36 weeks= FBE (if Hb low in 28 weeks), GBS swab ( high vaginal swab), anti-D administration if Rh neg
what are some routine examinations we perform at antenatal visits?
BP, fundal height (symphysis pubis to top of the uterus, serial measurements), weight gain, Lie, Presentation, Station, foetal heart auscultation (pick up an arrhythmia),
Urinalysis (test for protein! Every woman must have this done at each visit).
What are some ix we need to perform at the first antenatal visit and why?
FBE= looking for anaemia and thalassemia (think thalassemia minor causing low MCV)
Varicella ab- if not and exposed to VZV, need to administer hyperimmune VZIG
Hep B= immunisation and Ig at birth for neonate
Hep C= avoid invasive procedures
HIV= reduce risk of vertical transmission
Syphillis- intrapartum penicillin
MSU- 6% of women have asymptomatic bacteriuria–> 1/3 will develop pyelonephritis
Pap smear- treat before pregnancy
what is some general advice that we give to women on their first antenatal visit?
Diet- advise about Listeria (anything frozen needs to properly thawed eg frozen chicken; avoid mayonaisse; soft serve icecream) and nutrition (protein, avoid junk food, low GI foods etc)
Mineral and vitamin supplementation- (Vegetarian- Fe; dark skinned or heavily covered- ca2+ and vit D; folate –>MTHFR mutation (thrombophilia); iodine in multivitamin)
Exercise- strenuous exercise is not good but moderate exercise is good
-avoid Smoking
Alcohol- avoid > 2 standard drinks as day
Sex- no harm demonstrated
Working- most cease work around 34 weeks
Medication- Paracetamol (?hyperactivity); penicillins; etc
what is naegele’s rule?
Naegele’s rule is used to calculate the estimated delivery date (EDD).
First day of LMP + 9 months and 7 days= EDD
Adjust for variable cycles (follicular stage may be short or long but luteal phase constant)
what do we mean by CRL and BPD in antenatal dating ultrasounds?
CRL= crown rump length of embryo on ultrasound. For less than 12 weeks gestation, CRL guides EDD.
BPD= biparietal diameter for the fetal head. For > than 12 weeks gestation, BPD guides EDD
For greater than 20 weeks gestation, both CRL and BPD on ultrasound is very inaccurate for estimating delivery date
when should a pregnant woman see her healthcare provider weekly?
> 36 weeks gestation
when should a pregnant woman see her healthcare provider fortnightly?
28-36 weeks gestation
fundal height at the umbilicus generally indicates which gestation week?
20 weeks of gestation
at 12 weeks of gestation, where should the fundal height be?
at the pubic symphysis
what are the 4 Ms of diabetes mellitus related poor pregnancy outcomes?
Malformation
Miscarriage
Mortality
Macrosomia
when should nuchal translucency be measured?
11-13 weeks gestation
what is the relationship between nuchal translucency and down’s syndrome?
increased diameter of nuchal translucency–> more likely that the child has T21.
which antenatal u/s scan is the most important?
the one performed at around 20 weeks gestation as it is most sensitive at picking up congenital defects etc
what can a quantitative measurement of bHCG tell us about a pregnancy?
bHCG levels should DOUBLE every 48 hours in a normal pregnancy from week 4-8. Falling levels indicate non-progression of the pregnancy
what is the definition of hyperemesis gravidarum?
persistent vomiting accompanied by weight loss > 5%, dehydration and ketouria
diagnosis of exclusion
at what gestation period do we normally see hyperemesis gravidarum
up to 10 weeks gestation
define miscarriage?
the loss of a pregnancy less than 20 weeks gestation
what is the percentage of miscarriages in all diagnosed pregnancies?
15-20% of diagnosed pregnancies will be miscarried
when should we see a viable fetus on transvaginal and transabdominal u/s respectively?
from 5.5 weeks transvaginally
from 6.5weeks transabdominally
what are the three broad ways we can manage miscarriages?
expectant (watch and wait)
medical- misoprostol
surgical- suction and curattage
what is the biochemical pattern of maternal serum during first/2nd trimester screening that is classic for T21 anomaly?
The pattern of biochemical abnormalities in a pregnancy affected by Down syndrome is a reduced alpha-fetoprotein and oestriol, and an elevated inhibin and β-hCG
Describe first trimester combined screening?
nuchal translucency u/s
maternal PAPP-A and bHCG serum test
With first-trimester combined screening, patients have a blood test performed at 9 to 12 weeks followed by an ultrasound at 11 to 13 weeks
what is the difference between CVS and amniocentesis?
these are both ways to diagnose aneuploidy.
amniocentesis- needle passed through the maternal abdominal wall to sample aminiotic fluid for analyse.
-performed at 15weeks gestation.
CVS- needle inserted into the placenta to aspirate chorionic villi
- performed at 12-14 weeks gestation
- higher risk of miscarriage 1% but usually first line ix
other than increased nuchal translucency diameter on u/s, what other sonographical sign might indicate chromosomal abnormalities?
abnormal blood flow through the ductus venosus
considering the pregnancy is > 20 weeks gestation and has thus proceeded without complication, what are some late pregnancy problems that we routinely monitor for during antenatal visits?
placental insufficiency and preeclampsia
in what trimester do we consider foetal movements an important part of antenatal care and why?
in the third trimester.
generally a parameter of foetal wellbeing
what advice can we give a mother during her antenatal visits to assess change in fetal movements?
check with meal times- check the whether the baby moves during meals or within the next half hr or so thereafter
during your antenatal consultation, you examine the abdomen for fundal height etc. the woman complains of feeling dizzy. what do you advise?
turning onto lateral side to relieve aorto-caval pressure
what is a common cause of a fundal height that is lower than you would expect?
transverse lie of baby
at which point of the maternal abdomen can we auscultate the foetal heart the best using a doppler u/s?
The point of maximal intensity is over the area of abdomen which is related to the left chest wall of the fetus, but is often only determined by trial and error.
what is the main reason we auscultate the foetal heart during an antenatal consultation?
to detect foetal heart arhthymias such as brady/tachycardia or heart block–> may be a sign of anaemia or hydrops
why do we perform a maternal FBE blood test at 28 weeks gestation?
There is a normal fall in haemoglobin during pregnancy with a trough at approximately 28 weeks’.
For various reasons, particularly iron deficiency, the haemoglobin may fall excessively and therapy may be indicated.
when should a woman planning on becoming pregnant/is pregnant be on folate supplementation?
before pregnancy and up to 12 weeks gestation
which women should take iron supplements during pregnancy?
Women who have iron deficiency anemia will need additional supplementation, with a specific iron supplement, containing at least 60 mg of iron daily.
Women with additional iron needs in pregnancy, such as multiple births or decreased dietary iron intake (e.g. vegetarians), should also take iron supplements.
why do we make a big deal about screening for trisomy 21 rather than trisomy 18/13?
trisomy 21 is a chronic lifelong condition which will affect both the parents and child. it is the most common aneuploidy congenital defect. trisomy 18/13 rarely survive to term and often miscarriage.
what does maternal age screening mean with regard to antenatal screening for Down’s syndrome?
maternal age > 37 years is classified a POSITIVE screening test result, warranting invasive procedures like amniocentesis and CVS to determine whether the baby is affected with T21 or not
what are the maternal serum markers screened for during the 2nd trimester screening?
bHCG, oestriol, inhibin and alpha feto protein
what patterns of 2nd trimester maternal serum markers may indicate trisomy 21?
reduced fetal markers (oestriol and alpha feto protein) and elevated placental markers (bHCG and inhibin)
what is the disadvantage of using nuchal translucency as a marker of down syndrome in first trimester u/s?
it requires sonographers who are trained in detecting and measuring nuchal translucency i.e. accurate measurement is operator dependent.
why is it important to do u/s and serum markers together as a COMBINED screening test for down’s syndrome?
increases sensitivity of the test in picking up T21 i.e. detection rate is higher
why is it better to have screening tests of higher sensitivity for Down’s syndrome than a diagnostic test?
diagnostic tests like amniocentesis/CVS are invasive and so if we can increase the sensitivity of screening tests then we can reduce the requirement of diagnostic tests
what does NIPS refer to in antenatal screening and why is it important to know about?
NIPS stands for non-invasive prenatal screening. It refers to process of using maternal plasma to pick up cell-free fetal DNA. The detection rate of this screening test is almost 99% (highest specificity and sensitivity) for Down’s syndrome.
While it is becoming increasingly common to use this test, you need to remember that it is NOT a diagnostic test for Down’s, and so invasive sampling for fetal cells is still required for diagnosis
what does a ‘soft marker’ of Down’s syndrome refer to?
soft marker of Down’s syndrome is a physical feature on u/s which is characteristic of T21 but does not pose any immediate health risk to the baby
other than its implications for Down’s syndrome, what can a low PAPP-A and bHCG indicate in the first trimester?
can indicate intrauterine growth restriction
what might elevated an alpha feto protein serum marker in the second trimester screen indicate? What might be required in the 3rd trimester?
may indicate neural tube defects, exomphalos, and other structural defects.
if the u/s is normal at the 2nd trimester morphology screen, the woman may need subsequent growth scans to monitor fetal growth
parents are concerned that their unborn baby may have CF. what screening test could you offer them to check whether they are carriers and how good is it?
can offer them to do cheek (buccal) swabs or blood test however this test only picks up 85% of carriers
a pregnant woman is found to be beta thalassaemia minor. what is your next line of action?
screen the partner for beta-thalassaemia. if beta-thalassaemia minor is also detected in partner, then baby has 1/4 chance of developing thal major and prenatal invasive testing for confirmation (i.e. amnio/CVS) should be offered
which women are at high risk of large structural malformations in their baby and what dose of folate do we ask them to take during pre-pregnancy and antenatal counselling?
women who are on certain teratogenic agents such as anti-epileptics/lithium etc, women with perinatal infections, women with diabetes, women who are obese and women with a positive family history of malformations.
advise them to take high dose folate - 5mg daily
a pregnant woman has a history of 3 x loop/leetz procedures for CIN 3. what can you do antenatally to prevent preterm labour as a result of cervical insufficiency?
- elective cervical suture/cerlcage during early pregnancy and then removed towards the end of pregnancy
- cervical progesterine plessary nocte
when do we do a 2nd trimester combined screening?
if required between 15-20 weeks gestation
a woman has her first trimester screen and it reveals low PAPPA but normal for everything else. what is she at risk of and how do we manage this?
IUGR
regular growth scans
when do we give the whooping cough vaccination?
28 weeks to both pregnant woman and her partner
when is u/s sensitive at predicting EDD?
before 13 weeks gestation; ideally the earlier the better around 9 weeks
what foods do we find listeria in?
soft cheeses, soft serve icecream, unpasteurised milk, mayonaisse
what is a common benign cause of early pregnancy pain?
corpus luteal cyst haemorrhage
when do we start treating iron deficiency in pregnancy with iron supplements?
when ferritin is less than 20ug/L
at what gestation week would be consider induction due to prolonged/post date pregnancy?
40 weeks and 10 days
when do we consider prescribing aspirin during pregnancy?
if there is a risk of placental insufficiency such as history of IUGR or preeclampsia, women are advised to take low dose aspirin in subsequent pregnancies.
The benefits of aspirin have only been shown when commenced before 16 weeks
