Chapter 25: OB Flashcards by David Hopkins

What should you order (diagnostic test) for a female patient who comes in on birth control pills presenting with amenorrhea?

Pregnancy test

No form of pregnancy, even tubal ligation is 100% effective

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What is the Hegar sign?

A sign of pregnancy:
- Softening & compressibility of the lower uterine segment

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What is the Chadwick sign?

A sign of pregnancy:
- Color change of the vulva, cervix, and vaginal walls
- Often darkening or becoming bluish

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{{BLANK}} is termed the “mask of pregnancy” which occurs due to estrogen secretion.

Melasma/Chloasma

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{{BLANK}} is the linear stripe of hyperpigmented skin across the abdomen.

Linea nigra

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Why is gestational age typically used to date pregnancy?

Measures (in weeks) the first day of the patient’s last menstrual period (FDLMP)
More reliable calculation (versus embryonic age) as the FDLMP is a rather clear assessment

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What are the (4) ways pregnancy is diagnosed?

Detection of beta-hCG in blood or serum
Detection of beta-hCG in urine
Detection of gestational sac, yolk sac, or fetal pole by TVUS
Detection of fetal cardiac activity on doppler U/S

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Visualization of a gestational sac via TVUS typically correlates with a serum beta-hCG of {{BLANK}}.

1,000 to 2,000 mIU/mL

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Visualization of a gestational sac via TAUS typically correlates with a serum beta-hCG level of {{BLANK}}.

5,000 to 6,000 mIU/mL

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What is Naegele’s rule?

EDD = LMP - 3 months + 7 days

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Provide vitamin & dose in your answer

{{BLANK}} is a vitamin that should be recommended to all women of reproductive age.

Folic Acid (Vitamin B9) 400 micrograms/day

For the prevention of neural tube defects

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What is the most critical window for the initiation of Folic Acid (vitamin B9) regarding neural tube defects?

First trimester

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What are the (11) lab tests that are recommended by ACOG to be performed in every pregnant patient on their first prenatal visit?

Hgb, Hct, Plt count
Blood type, Rhesus (Rh) factor, Rhesus (Rh) antibody screen
VDRL/RPR test for syphilis
Hepatitis B surface antigen (HBsAg) screen
HIV
Rubella antibody titer
UA & Urine Culture

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How often should a pregnant patient attend antenatal visits?

q 4 weeks until 28 weeks
q 2 weeks until 36 weeks
q weekly until 40 weeks
bi-weekly until 42 weeks

Note the increase in frequency as the patient nears due date

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Fetal heart sounds can be first noted around {{BLANK}} weeks pregnant via doppler U/S.

10 to 12 weeks

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Fetal heart sounds can be first noted around {{BLANK}} weeks pregnant via auscultation with a normal stethescope.

16 to 20 weeks

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Around week {{BLANK}} the uterine fundus becomes palpable above the pubic symphysis.

Week 12

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Fundal height is at the level of the umbilicus at week {{BLANK}}.

Week 20

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What is the significance of fundal height in regards to pregnancy dating?

Distance in cm from pubic symphysis to the top of the uterine fundus
1 cm = 1 week
Level of umbilicus = 20 weeks gestation

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What is a size/date discrepancy?

Difference of 2-3 cm between measured fundal height and gestational age

Most common cause –> incorrect EDD

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If a size/date discrepancy is noted, you should perform {{BLANK}} to further investigate.

U/S

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Dating by U/S is more accurate when performe during the {{BLANK}} trimester.

First trimester

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The most accurate first-trimester estimation of gestational age is achieved by measuring the {{BLANK}}.

Crown-rump length (CRL)

Can be performed ~5.5 weeks gestation

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Starting at week {{BLANK}}, gestational age is measured via four fetal biometric characteristics: fetal head circumference, biparietal diameter, abdominal circumference, and femur length.

The biparietal diameter is considered the most reliable.

Week 14

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What are the (4) biometric characteristics used to measure gestational age at **week 14**? Which is considered the most reliable?

- Fetal head circumference - Biparietal diameter (most reliable) - Abdominal circumference - Femur length

How is **fetal biparietal diameter (BPD)** measured?

Distance between the outer edge of the proximal skull to the inner edge of the distal skull

Which landmarks must be visible to ensure an accurate **fetal biparietal diameter (BPD)** measurement?

- Third ventricle - Thalami | These structures must be present to ensure accuracy

{{BLANK}} and {{BLANK}} are the most common factors leading to **symmetric IUGR**.

- Congenital infections - Teratogen exposure

What are (4) factors leading to **asymmetric IUGR**? Which is most common?

- Uteroplacental dysfunction (most common) - Preeclampsia - Placental abruption - Twin-twin transfusion

{{BLANK}} is the easiest initial screen for fetal well-being.

Non-stress test (NST)

How is a **non-stress test (NST)** performed?

- Fetal HR tracing x 20 minutes - Normal ≥ 2 accelerations - Gestational Age ≥ 32 weeks then each acceleration must be ≥ 15 bpm above baseline & last ≥ 15 seconds - Gestational Age ≤ 32 weeks then each acceleration must be ≥ 10 bpm above baseline & last ≥ 10 seconds

What makes up a **biophysical profile (BPP)**?

- Non-stress test - U/S | U/S includes breathing, movement, tone, HR, amniotic fluid index

What are the factors evaluated during **U/S** when gathering a patient's **biophysical profile (BPP)**?

1. Breathing 2. Movement 3. Muscle tone 4. Heart rate 5. Amniotic fluid index

If a fetus scores poorly on **biophysical profile (BPP)** evaluation, then you should perform the {{BLANK}} test. Why?

**Contraction stress test** - Evaluates for uteroplacental dysfunction

How is the **contraction stress test** performed? How do you evaluate the test? What if the test is positive?

- **Oxytocin** is given & fetal HR is monitored - If **late decelerations** are seen with each contraction, the test is **positive** - If positive, a **cesarean section** is performed

T/F: A **biophysical profile (BPP)** is often used in high-risk pregnancies despite the absence of obvious problems.

True | May be done up to bi-weekly starting at 3rd trimester

What is **quickening**? When is it usually felt?

- When first **fetal movements** are **felt** - Usually occurs from week 16 (but can occur as late as week 20)

{{BLANK}} can be given during pregnancy to reduce the frequency of **pre-eclampsia** and related adverse outcomes such as preterm birth and growth restriction when given to a women at moderate to high risk of the disease.

**Low dose aspirin (ASA)**

What are (4) diseases that may confer an increased risk of **pre-eclampsia** and may prompt the provider to prescribe **low dose aspirin**?

1. Previous pregnancy w/ pre-eclampsia 2. CHTN 3. T1DM/T2DM 4. CKD | Also consider in obesity, FMH of pre-eclampsia, obesity, Age ≥ 35 yo

What is post-term pregnancy? Why should you be concerned? How do you treat it?

- Definition: **Gestation > 42 weeks** - Complications: **Dystocia** is more common along with placental insufficiency or meconium aspiration - Tx: **Induction of labor**

When is testing of **maternal alpha-fetoprotein (AFP)** most accurate?

Weeks 15 to 20 | Low: down syndrome, fetal demise, inaccurate dating; high: NTD, VWD

What should be done if **alpha-fetoprotein (AFP)** is found elevated?

Repeat the test | ~30% of elevated AFP cases are normal upon repeat testing

If a patient's **alpha-fetoprotein (AFP)** is found to be elevated after follow up testing, you should have the patient undergo {{BLANK}}.

U/S | Look for NTD or abdominal anomaly

If a patient has elevated **alpha-fetoprotein (AFP)** measurements x 2 and **U/S** is uncertain of findings (e.g., NTD), then you should have the patient undergo {{BLANK}}.

Amniocentesis | Can be performed at 15-20 weeks gestation

The **first trimester combined test** is performed at {{BLANK}} weeks of gestation. | Includes U/S for nuchal translucency, PAPP-A, beta-hCG

Between **11 to 13 weeks** gestation

What is included in the **first trimester combined test**?

- **U/S for nuchal translucency** - Pregnancy-associated plasma protein-A (**PAPP-A**) - **beta-hCG**

If a patient has an abnormal **first trimester combined test** then you should perform {{BLANK}} to confirm the diagnosis.

Chorionic villus sampling (CVS)

What are the **full-integrated screening tests**? When are they performed?

- *Weeks 10-13*: **PAPP-A** and **U/S for nuchal translucency** - *Weeks 15-18*: **AFP**, **uE3**, **hCG**, and **inhibin A**

How is the **serum-integrated screening test** differentiated from the **full-integrated screening test**?

**Serum-intregrated screening testing** does **not** include U/S to evaluate for nuchal translucency

What does the **quadruple test** include? For whom is it used? When?

- Quadruple test: **AFP**, **uE3**, **hCG**, and **inhibin A** - For those that present during the 2nd trimester - **Week 15 to 18 gestation**

{{BLANK}} is a new maternal plasma-based test used to evaluate fetal DNA in maternal circulation.

Cell-free fetal DNA (**cfDNA**) testing | Detection rate: 98%, FP rate: 1%, FN rate: 1.4%

What is the next step if a woman has a positive screening test for **Down syndrome**? How is this evaluated?

**Karyotype determination** - Weeks 10-15: CVS - Weeks 15-20: amniocentesis

What are the S/Sx of a **hydatidiform mole**?

- Very high **hCG** - **Hyperemesis** (& hyperemesis gravidarum) - Expulsion of "grape-like" tissue from the vagina - **Snowstorm** appearance on **U/S** (complete mole)

What is the karyotype for: 1. **Complete hydatidiform mole** 2. **Partial hydatidiform mole**

1. 46 XX or 46 XY 2. 69 (usually XXY)

How are **hydatidiform moles** treated?

- D&C - Serial hCG measurements | If hCG fails to fall to zero --> invasive mole or choriocarcinoma

**Choriocarcinoma** occurring post-hydatidiform mole D&C is best treated via {{BLANK}} or {{BLANK}}.

- Methotrexate (MTX) - Dactinomycin

{{BLANK}} are contraindicated during pregnancy as they may cause **yellow or brown teeth** discoloration.

Tetracyclines (TCNs)

{{BLANK}} is contraindicated during pregnancy as it causes **phocomelia** (i.e., absence of long bones w/ "flipper-like" appearance of hands).

Thalidomide

{{BLANK}} are contraindicated during pregnancy as they are **nephrotoxic** and **ototoxic**.

Aminoglycosides

{{BLANK}} is a teratogenic medication known to cause **neural tube defects** and **hypospadias**.

Valproic Acid

{{BLANK}} is contraindicated during pregnancy as it can lead to the **masculinization of a female fetus**.

Progesterone

{{BLANK}} use during pregnancy can lead to **IUGR**, **low birth weight**, and **prematurity**.

Cigarette

{{BLANK}} use during pregnancy can lead to **right heart abnormalities (e.g., Ebstein anomaly)**.

Lithium

{{BLANK}} use during pregnancy is contraindicated as it can lead to **craniofacial, limb, and cerebrovascular defects** along with **intellectual disability** and **fetal hydantoin syndrome**.

Phenytoin

{{BLANK}} use during pregnancy can lead to **craniofacial defects, IUGR, CNS malformation, and stillbirth**.

Warfarin

{{BLANK}} use during pregnancy can lead to **fingernail hypoplasia, craniofacial defects, and fetal hydantoin syndrome**.

Carbamazepine

{{BLANK}} use during pregnancy can lead to **CNS, craniofacial, ear, and cardiovascular defects**.

Isotretinoin

{{BLANK}}, in excess, can lead to **goiter and neonatal hypothyroidism**.

Iodine

{{BLANK}} use during pregnancy can lead to **cerebral infarcts and intellectual disability**.

Cocaine

**Diazepam** use during pregnancy can lead to?

Cleft lip/palate

{{BLANK}} use during pregnancy can lead to **clear cell vaginal cancer, adenosis, and cervical incompetence**.

Diethylstilbestrol (DES)

What is the definition of **macrosomia**?

Fetus/Newborn > 4,000 g (~9 lbs) | The cause is maternal DM until proven otherwise

You should treat **infantile hypoglycemia** due to **GDM/DM** via {{BLANK}}.

IV glucose

T/F: There is an increase in **respiratory distress** in patients born to mothers with diabetes.

True

Why is **insulin** typically the only agent used to treat **DM** of pregnancy?

It does not cross the placenta as oral agents may | Decreased risk of intrapartum fetal hypoglycemia

What is the typical treatment of **GDM**? What if that does not work?

1. Lifestyle modifications: **diet & exercise** 2. Insulin