3. Antepartum Care Flashcards by Jimmy Chau

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

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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

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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

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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

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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.

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Describe etiology: Hyperemesis Gravidarum (2)

multifactorial with hormonal, immunologic, and psychological components
rapidly rising β-hCG ± estrogen levels may be implicated

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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

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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

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Describe complications MATERNAL: Hyperemesis Gravidarum (4)

dehydration, electrolyte, and acid-base disturbances
Mallory-Weiss tear
Wernicke’s encephalopathy, if protracted course
death

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Describe complications FETAL: Hyperemesis Gravidarum (2)

usually none
intrauterine growth restriction is 15x more common in women losing >5% of pre-pregnancy weight

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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

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When to perform Leopold’s Maneuvers? (1)

performed after 30-32 wk gestation

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Describe Leopold’s Maneuvers (4)

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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

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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

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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

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Describe: Amniocentesis (1)

U/S-guided transabdominal extraction of amniotic fluid performed as early as 15 weeks GA

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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)

* **D**eath of fetus * **A**mniotic fluid decreased * **S**leep cycle of fetus * **H**unger/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 * **L**imb extension + flexion * **A**FV 2 cm x 2 cm * **M**ovement (3 discrete) * **B**reathing (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