3. Antepartum Care Flashcards
Describe preconception supplementation (2)
-
folic acid: encourage diet rich in folic acid and consider supplementation from 8-12 wk pre- conception until end of T1 to prevent neural tube defects
- 0.4-1 mg daily in all women; 5 mg if previous NTD, antiepileptic medications, DM, or BMI >35 kg/m2
- iron supplementation (in cases of iron deficiency anemia), prenatal vitamins
How to estimate the due date? (3)
- Naegele’s rule: 1st day of LMP + 1 year + 7d – 3 mo
- e.g. LMP = 1 Apr 2014, EDD = 8 Jan 2015 (modify if cycle >28 d by adding number of d >28)
- EDD by LMP not reliable if irregular menstrual cycle, or if patient unsure of the LMP
Describe non-pharmacological management of nausea and vomiting (6)
- frequent small meals (bland, dry, salty are better tolerated), encourage any safe appealing foods
- electrolyte oral solutions (Pedialyte®, Gatorade®)
- stop prenatal vitamins and if T1, substitute with folic acid or adult/children’s vitamins that are low in iron
- increase sleep/rest
- ginger (maximum 1000 mg/d)
- acupuncture, acupressure, and mindfulness-based cognitive therapy
Describe pharmacological management of nausea and vomiting (4)
- first line: pyridoxine (B6) monotherapy or doxylamine/pyridoxine (Diclectin) combination 4 tablets PO daily (1 q am, 1 q lunch and 2 qhs) up to maximum of 8 tablets/d
- H1 receptor antagonists should be considered for acute or chronic episodes of N/V in pregnancy
- metoclopramide and phenothiazines can be used as an adjunctive therapy for severe N/V in pregnancy
- Ondansetron if severe N/V and other anti-emetics have failed
Describe: Hyperemesis Gravidarum (3)
- intractable N/V
- usually presents in T1 then diminishes; occasionally persists throughout pregnancy
- Wikipedia: is a pregnancy complication that is characterized by severe nausea, vomiting, weight loss, and possibly dehydration. Feeling faint may also occur.
Describe etiology: Hyperemesis Gravidarum (2)
- multifactorial with hormonal, immunologic, and psychological components
- rapidly rising β-hCG ± estrogen levels may be implicated
Describe investigations: Hyperemesis Gravidarum (2)
- rule out systemic causes: GI, pyelonephritis, thyrotoxicosis
- rule out other obstetrical causes: multiple gestation, gestational trophoblastic neoplasia (GTN), HELLP syndrome
- CBC, electrolytes, BUN, creatinine, liver function test (LFTs), urinalysis
- U/S
Describe manamgenet: Hyperemesis Gravidarum (7)
- thiamine supplementation may be indicated
- non-pharmacological
- pharmacological options
- doxylamine/pyridoxine
- dimenhydrinate can be safely used as an adjunct to Diclectin® (1 suppository bid or 25 mg PO qid)
- other adjuncts: hydroxyzine, pyridoxine, phenothiazine, metoclopramide
- also consider: ondansetron or methylprednisolone (avoid steroids in T1 due to increased risk of oral clefting)
- if severe: admit to hospital, NPO initially then small frequent meals; correct hypovolemia, electrolyte disturbance, and ketosis; total parenteral nutrition TPN (if very severe) to reverse catabolic state
Describe complications MATERNAL: Hyperemesis Gravidarum (4)
- dehydration, electrolyte, and acid-base disturbances
- Mallory-Weiss tear
- Wernicke’s encephalopathy, if protracted course
- death
Describe complications FETAL: Hyperemesis Gravidarum (2)
- usually none
- intrauterine growth restriction is 15x more common in women losing >5% of pre-pregnancy weight
Describe frequency of prenatal visits (4)
- usually within 8-12 wk of the 1st day of LMP or earlier if <20 or >35 yr old, bleeding, very nauseous, or other risk factors present
- after, for uncomplicated pregnancies, SOGC recommends
- q4-6 wk until 30 wk
- q2-3 wk from 30 wk,
- and q1-2 wk from 36 wk until delivery
When to perform Leopold’s Maneuvers? (1)
- performed after 30-32 wk gestation
Describe Leopold’s Maneuvers (4)
Describe: Ultrasound screening (9)
- 8-12 wk GA: dating U/S (most accurate form of pregnancy dating)
- measurement of crown-rump length (margin of error: ± 5 d)
- EDD should be based on T1 U/S if available
- 11-14 wk GA: nuchal translucency ultrasound (NTUS)
- measures the amount of fluid behind the neck of the fetus
- early screen for Trisomy 21 (may also detect cardiac and other aneuploidies like Turner syndrome)
- NT measurement is necessary for the FTS and IPS Part 1
- 18-20 wk GA: growth and anatomy U/S (margin of error: ± 10 d)
- earlier or subsequent U/S performed when medically indicated
Describe: NON-INVASIVE PRENATAL TESTING (NIPT) (2)
- analyses maternal blood for circulating cell-free fetal DNA (ccffDNA) at 9-10 wk GA onwards.
- Requires dating U/S for accuracy
Name indications: NON-INVASIVE PRENATAL TESTING (NIPT) (3)
- age >35 yr (increased risk of chromosomal anomalies)
- risk factors in current pregnancy
- abnormal U/S
- abnormal prenatal screen (IPS, eFTS, or MSS)
- past history/family history of:
- chromosomal anomaly or genetic disease
- either parent a known carrier of a genetic disorder or balanced translocation
- consanguinity
- >3 spontaneous abortions
Describe: Amniocentesis (1)
U/S-guided transabdominal extraction of amniotic fluid performed as early as 15 weeks GA
Name indications: Amniocentesis (4)
- identification of genetic and chromosomal anomalies (15-16 wk gestation) as per indications above
- confirmation of positive non-invasive prenatal testing NIPT testing
- positive eFTS/IPS/MSS
- assessment of fetal lung maturity (T3) via the L/S ratio (lecithin:sphingomyelin)
- if >2:1, RDS is less likely to occur
Describe: CHORIONIC VILLUS SAMPLING (1)
biopsy of fetal-derived chorion using a transabdominal needle or transcervical catheter at 10-12 wk
Name risk Factors for Neural Tube Defects (5)
GRIMM
- Genetics: family history of NTD (risk of having second child with NTD is increased to 2-5%), consanguinity, chromosomal (characteristic of Trisomy 13, 18, and 21)
- Race: European Caucasians > African Americans, 3-fold higher in Hispanics
- Insufficient vitamins: zinc and folate
- Maternal chronic disease (e.g. DM)
- Maternal use of antiepileptic drugs
Describe: ISOIMMUNIZATION SCREENING (1)
isoimmunization: antibodies (Ab) produced against a specific RBC antigen (Ag) as a result of antigenic stimulation with RBC of another individual
Describe etiology: Isoimmunization (4)
- maternal-fetal circulation normally separated by placental barrier, but sensitization can occur and can affect the current pregnancy, or more commonly, future pregnancies
- anti-Rh Ab produced by a sensitized Rh-negative mother can lead to fetal hemolytic anemia
- risk of isoimmunization of an Rh-negative mother with an Rh-positive ABO-compatible infant is 16%
- sensitization routes
- incompatible blood transfusions
- previous fetal-maternal transplacental hemorrhage (e.g. ectopic pregnancy, abruption)
- invasive procedures in pregnancy (e.g. prenatal diagnosis, cerclage, D&C)
- any type of abortion
- labour and delivery
- trauma (e.g. car accident, fall, etc.)
Describe investigations: isoimmunization (5)
- screening with indirect Coombs test at first visit for blood group, Rh status, and antibodies
- Kleihauer-Betke test used to determine extent of fetomaternal hemorrhage by estimating volume of fetal blood volume that entered maternal circulation
- detailed U/S for hydrops fetalis
- middle cerebral artery Dopplers are done to assess degree of fetal anemia; if not available, bilirubin is measured by serial amniocentesis to assess the severity of hemolysis
- cordocentesis for fetal Hb should be used cautiously (not first-line)
Describe prophylaxis: Isoimmunization (1)
exogenous Rh IgG (Rhogam® or WinRho®) binds to Rh antigens of fetal cells and prevents them from contacting maternal immune system
Rhogam® (120-300 µg) given to all Rh negative and antibody screen negative women in the following scenarios (7)
- routinely at 28 wk GA (provides protection for ~12 wk)
- within 72 h of the birth of a Rh positive fetus
- with any invasive procedure in pregnancy (CVS, amniocentesis)
- as part of management of ectopic pregnancy
- with miscarriage or therapeutic abortion
- with an antepartum hemorrhage
- with trauma
Describe treatment: isoimmunization (3)
- falling biliary pigment warrants no intervention (usually indicative of either unaffected or mildly affected fetus)
- intrauterine transfusion between 18-35 wk GA of O-negative packed RBCs may be required for severely affected fetus
- early delivery of the fetus for exchange transfusion following 35 wk GA
Describe complications: isoimmunization (2)
- anti-Rh IgG can cross the placenta and cause fetal RBC hemolysis resulting in fetal anemia, CHF, edema, ascites
- severe cases can lead to hydrops fetalis (edema in at least two fetal compartments due to fetal heart failure secondary to anemia) or erythroblastosis fetalis (moderate to severe immune-mediated hemolytic anemia)
Patients will generally first notice fetal movement (“quickening”) when? (3)
- at 18-20 wk in primigravidas
- can occur 1-2 wk earlier in multigravidas
- can occur 1-2 wk later if placenta is implanted on the anterior wall of uterus
If the patient is concerned about decreased fetal movement, she is counselled to do what? (1)
to choose a time when the fetus is normally active to count movements (usually recommended after 26 wk)
All high-risk women should be told to do fetal movement FM counts when? (3)
- ≥6 movements in 2 h expected
- If there is a subjective decrease in fetal movement, time how long it takes to feel 10 discreet movements, laying on the left in a quiet setting may facilitate feeling subtle movements
- if 10 movements take more than 2 h, further assessment is indicated, and patient should present to labour and delivery triage for non-stress test
Name DDx of Decreased Fetal Movements (4)
- Death of fetus
- Amniotic fluid decreased
- Sleep cycle of fetus
- Hunger/Thirst
Describe: NON-STRESS TEST (2)
- FHR tracing ≥20 min using an external Doppler to assess FHR and its relationship to fetal movement
- Indication: any suggestion of uteroplacental insufficiency or suspected compromise in fetal well-being
Describe: Normal NST (3)
- 2 accels
- >15 bpm from baseline
- lasting >15 s in 20 min
Describe normal/atypical/abnormal tracing: Baseline
- Normal: 110-160 bpm
- Atypical:
- 100-110 bpm or >160 bpm for <30 min
- Rising baseline
- Abnormal:
- Bradycardia <100 bpm
- Tachycardia >160 for >30 min
- Erratic baseline
Describe normal/atypical/abnormal tracing: Variability
- Normal:
- 6-25 bpm (moderate)
- ≤5 (absent or minimal) for <40 min
- Atypical:
- 5 (absent or minimal) for 40-80 min
- Abnormal:
- ≤5 for 80 min
- Sinusoidal
- 25 bpm for >10 min
Describe normal/atypical/abnormal tracing: Decelerations
- Normal: None or occasional variable <30 s
- Atypical: Variable decelerations, 30-60 s duration
- Abnormal:
- Variable decelerations >60 s
- Late deceleration(s)
Describe normal/atypical/abnormal tracing: Accelerations in Term Fetus
- Normal:
- 2 accelerations with acme of ≥15 bpm, lasting 15 s over
<40 min of testing
- Atypical:
- 2 accelerations with acme of ≥15 bpm, lasting 15 s in
40-80 min
- Abnormal: <2 accelerations with acme (peak) of contraction of ≥15 bpm, lasting 15s in >80 min
Describe normal/atypical/abnormal tracing: Accelerations in Preterm Fetus (<32 wk)
- Normal: >2 accelerations with acme of >10 bpm, lasting 10 s in <40 min
- Atypical:
<2 accelerations with acme of >10 bpm, lasting 10 s in 40-80 min
- Abnormal: <2 accelerations with acme of >10 bpm, lasting 10 s in >80 min
Describe normal/atypical/abnormal tracing: Action
- Normal: FURTHER ASSESSMENT OPTIONAL, based on total clinical picture
- Atypical: FURTHER ASSESSMENT REQUIRED
- Abnormal: URGENT ACTION REQUIRED An overall assessment of the situation and further investigation with U/S or BPP is required; some situations will require delivery
Define: BIOPHYSICAL PROFILE (1)
U/S assessment of the fetus ± NST
Name indications: BIOPHYSICAL PROFILE (BPP) (4)
- post-term pregnancy
- decreased fetal movement
- intrauterine growth restriction IUGR
- any other suggestion of fetal distress or uteroplacental insufficiency
Describe: Scoring of the BPP
Describe interpretation of BPP score (3)
-
Reassuring BPP (8/8) LAMB. 8: perinatal mortality rate 1:1000; repeat BPP as clinically indicated
- Limb extension + flexion
- AFV 2 cm x 2 cm
- Movement (3 discrete)
- Breathing (one episode x 30 s)
- 6: perinatal mortality 31:1000; repeat BPP in 24 h
- 0-4: perinatal mortality rate 200:1000; deliver fetus if benefits of delivery outweigh risks
