RNC-OB practice test: 30 inpatient obstetric questions

A patient receiving magnesium sulfate at 2 g/h has had a urine output of 60 mL over the past 4 hours. DTRs are 1+ and respirations are 16/min. The nurse's priority is to

Pick the option you would mark on test day. The choice stays fixed, and every option then explains itself.

1. increase the infusion to 3 g per hour

   Increasing the infusion to 3 g per hour raises the dose while renal clearance is falling, which speeds toward toxicity.
2. notify the provider and check a Mg level

   Urine output of 60 mL in 4 hours is 15 mL/h, below the 30 mL/h minimum; magnesium is cleared by the kidneys, so the provider is notified and a serum level is checked before more is given.
3. document as expected and continue

   Documenting the findings as expected and continuing ignores oliguria and diminished reflexes, the early warning of magnesium accumulation.

A patient at 28 weeks with chronic hypertension has a BMI of 45. Which step before labor does ACOG advise?

1. A planned cesarean birth at 37 weeks

   A planned cesarean birth at 37 weeks has no basis in obesity or controlled chronic hypertension and adds surgical and wound risks.
2. An anesthesia consultation

   With class III obesity, ACOG advises an anesthesia consultation before labor, since airway management and neuraxial placement are harder and are planned ahead.
3. Stopping the antihypertensive agent

   Stopping the antihypertensive agent removes treatment that is recommended to keep pressure below 140/90 mm Hg in chronic hypertension.

A patient at 34 3/7 weeks with a singleton pregnancy and placenta previa has recurrent bleeding and is at high risk of birth within 7 days. She has not received corticosteroids and has no pregestational diabetes. The nurse anticipates

1. betamethasone per the late preterm protocol

   At 34 0/7 to 36 6/7 weeks with birth likely within 7 days and no earlier course, a single late preterm betamethasone course lowers newborn respiratory morbidity; pregestational diabetes is the main exclusion.
2. magnesium sulfate for neuroprotection

   Magnesium sulfate for neuroprotection is given when birth is expected before 32 weeks, not at 34 weeks.
3. nifedipine tocolysis for 48 hours

   Nifedipine tocolysis for 48 hours is not used after 34 weeks; the late preterm steroid course is given without tocolysis.

A patient at 37 weeks has spontaneous rupture of membranes with a sudden gush of bright red blood, immediately followed by fetal bradycardia. Maternal vital signs are stable, and the uterus is soft and nontender. The most likely cause is

1. vasa previa

   Bleeding at membrane rupture followed at once by fetal bradycardia, with a stable mother and a soft uterus, points to vasa previa: torn fetal vessels in the membranes, so the blood lost is fetal.
2. placental abruption

   Placental abruption usually brings abdominal pain and a firm, tender uterus, which this patient does not have.
3. marginal placenta previa

   A marginal placenta previa bleeds maternal blood, usually without sudden fetal bradycardia at the moment the membranes rupture.

A patient at 36 weeks has had right calf pain and swelling for 2 days. The first diagnostic test the nurse anticipates for suspected deep vein thrombosis is

1. a serum D-dimer level

   A serum D-dimer level rises normally in pregnancy, so it cannot confirm or reliably rule out a clot.
2. CT venography of the pelvis

   CT venography of the pelvis exposes the fetus to radiation and contrast and is not a first test; if an iliac clot is suspected and ultrasound is unclear, MR venography is preferred.
3. compression ultrasound of the leg

   Compression ultrasound of the leg is the first test for suspected deep vein thrombosis in pregnancy: no radiation, and a noncompressible vein confirms the clot.

For an uncomplicated monochorionic-diamniotic twin pregnancy, ACOG recommends planned birth at

1. 32 0/7 to 34 0/7 weeks

   32 0/7 to 34 0/7 weeks is the window for monoamniotic twins, whose cords can entangle.
2. 34 0/7 to 37 6/7 weeks

   ACOG times birth for uncomplicated monochorionic-diamniotic twins at 34 0/7 to 37 6/7 weeks, because the shared placenta raises the risk of late stillbirth.
3. 38 0/7 to 38 6/7 weeks

   38 0/7 to 38 6/7 weeks applies to uncomplicated dichorionic-diamniotic twins, which have separate placentas.

A patient at 30 weeks with gestational diabetes reviews her glucose log with the nurse. Which value is above the recommended pregnancy target?

1. 1-hour postprandial of 152 mg/dL

   The 1-hour postprandial target in gestational diabetes is below 140 mg/dL, so 152 mg/dL is too high.
2. 2-hour postprandial of 112 mg/dL

   A 2-hour postprandial of 112 mg/dL is within the 2-hour target of less than 120 mg/dL.
3. 1-hour postprandial of 128 mg/dL

   A 1-hour postprandial of 128 mg/dL is within the target of less than 140 mg/dL.

A patient at 20 weeks with monochorionic-diamniotic twins has an ultrasound showing a deepest vertical pocket of 9 cm around one twin and 1.5 cm around the other, whose bladder is not visible. The nurse anticipates referral for

1. fetoscopic laser photocoagulation

   A donor twin with a pocket under 2 cm and no visible bladder next to a recipient with a pocket of 8 cm or more is stage II twin-twin transfusion; at 16 to 26 weeks fetoscopic laser photocoagulation of the connecting vessels is the preferred treatment.
2. serial amnioreduction only

   Serial amnioreduction only relieves the excess fluid without treating the shared vessels, and survival is lower than with laser.
3. selective fetal reduction

   Selective fetal reduction ends one twin's life; it is kept for cases such as a severe anomaly or failed laser, not as the treatment for stage II disease.

The FHR tracing that meets the definition of Category III is

1. minimal variability and recurrent late decelerations

   Minimal variability with recurrent late decelerations is Category II: worrying, but variability is still present.
2. marked variability and recurrent late decelerations

   Marked variability with recurrent late decelerations is also Category II; only absent variability moves the tracing to Category III.
3. absent variability and recurrent late decelerations

   Category III requires absent variability together with recurrent late or variable decelerations or bradycardia, or a sinusoidal pattern.

Per NICHD, the onset-to-nadir time that separates an abrupt FHR deceleration, such as a variable deceleration, from a gradual one is

1. 15 seconds

   15 seconds is part of the size rule for a variable deceleration (a drop of at least 15 bpm lasting at least 15 seconds), not the onset-to-nadir cutoff.
2. 30 seconds

   NICHD calls a deceleration abrupt when the FHR reaches its nadir in less than 30 seconds, as in a variable deceleration, and gradual when it takes 30 seconds or more, as in early and late decelerations.
3. 2 minutes

   2 minutes is where a deceleration becomes prolonged; it measures total duration, not the time to the nadir.

The most accurate way to confirm gestational age, and so to time a scheduled birth, is

1. a third-trimester biparietal diameter scan

   A third-trimester biparietal diameter scan can be off by 3 weeks or more because fetal size varies late in pregnancy.
2. the date of first perceived fetal movement

   The date of first perceived fetal movement varies by weeks between patients and is too imprecise for dating.
3. a first-trimester crown-rump length ultrasound

   A first-trimester crown-rump length ultrasound dates a pregnancy within about 5 to 7 days and is the most accurate basis for timing a scheduled birth.

At 32 weeks, a patient's fundal height measures 27 cm. Dating was confirmed in the first trimester. The nurse anticipates

1. a contraction stress test this week

   A contraction stress test this week assesses placental reserve but does not measure growth, the question raised by a small fundal height.
2. a fetal growth ultrasound

   After 24 weeks, fundal height in centimeters should be within about 2 cm of the gestational week; 27 cm at 32 weeks lags by 5 cm, so a fetal growth ultrasound checks for growth restriction or low fluid.
3. reassurance that the size is normal

   Reassurance that the size is normal ignores a 5 cm lag with reliable dating.

During transcervical amnioinfusion for recurrent variable decelerations, the nurse monitors most closely for

1. maternal respiratory depression

   Maternal respiratory depression comes from opioids or magnesium, not from fluid instilled into the uterus.
2. a drop in maternal blood glucose

   A drop in maternal blood glucose is not a hazard of amnioinfusion, which uses isotonic saline or lactated Ringer's.
3. an elevated uterine resting tone

   Fluid infused faster than it drains can overdistend the uterus, so resting tone on the intrauterine catheter is watched most closely during amnioinfusion.

After the membranes have ruptured, the number of digital vaginal examinations is limited mainly to reduce the risk of

1. cervical edema

   Cervical edema comes from pressure of the presenting part or early pushing, not from the number of examinations.
2. umbilical cord prolapse

   Umbilical cord prolapse depends on rupture with an unengaged presenting part, not on how often the cervix is checked.
3. intraamniotic infection

   Each digital examination after membranes rupture can carry vaginal bacteria upward, so examinations are limited to lower the risk of intraamniotic infection.

Prolonged high-dose oxytocin given in large volumes of electrolyte-free IV fluid can cause

1. hypokalemic metabolic alkalosis

   Hypokalemic metabolic alkalosis follows vomiting or diuretics, not water retention from oxytocin.
2. dilutional hyponatremia

   Oxytocin has an antidiuretic effect, so high doses in large volumes of electrolyte-free fluid retain water and cause dilutional hyponatremia, with headache, confusion and even seizures.
3. hypercalcemic muscle weakness

   Hypercalcemic muscle weakness has nothing to do with oxytocin; calcium is not changed by its antidiuretic action.

On vaginal examination, the nurse palpates the diamond-shaped fontanel just behind the symphysis pubis. The fetal position is occiput

1. posterior

   The diamond-shaped anterior fontanel lies at the front of the fetal head, so finding it just behind the symphysis means the occiput faces the maternal back: occiput posterior.
2. anterior

   Occiput anterior would put the small triangular posterior fontanel behind the symphysis, not the diamond.
3. transverse

   In an occiput transverse position the sagittal suture runs side to side and the fontanels lie toward the maternal sides.

A tight nuchal cord cannot be reduced over the fetal head. A technique that allows birth while keeping the cord intact is the

1. McRoberts maneuver

   The McRoberts maneuver flexes the maternal thighs to free an impacted shoulder; it does nothing for a tight nuchal cord.
2. Woods screw maneuver

   The Woods screw maneuver rotates the fetal shoulders in shoulder dystocia and is unrelated to a nuchal cord.
3. somersault maneuver

   In the somersault maneuver the head is held flexed against the maternal thigh so the body somersaults out alongside it, leaving the tight nuchal cord intact.

To convert a labor epidural for cesarean birth, the sensory block usually must reach about

1. T4

   Cesarean birth needs a sensory block to about T4, the nipple line, to cover peritoneal handling.
2. T10

   T10, at the umbilicus, is enough for labor pain but too low for surgery.
3. L1

   L1 is far too low; it would not block the abdominal wall or the peritoneum.

Intradermal sterile water injections given over the sacrum during labor are used primarily to relieve

1. pruritus from neuraxial opioids

   Pruritus from neuraxial opioids is treated with drugs such as low-dose nalbuphine or naloxone.
2. occiput posterior back pain

   Sterile water papules over the sacrum relieve labor back pain, which is most intense with an occiput posterior fetus.
3. discomfort of epidural catheter insertion

   Discomfort of epidural catheter insertion is managed with local anesthetic infiltration of the skin, not sterile water.

The spontaneous urge to push during the second stage of labor is triggered mainly by

1. a fall in maternal oxytocin release

   A fall in maternal oxytocin release is the reverse of what happens; pelvic floor stretch increases oxytocin late in labor.
2. rupture of the membranes at full dilation

   Rupture of the membranes at full dilation is not the trigger; many patients feel the urge with intact membranes once the head descends.
3. presenting part pressure on pelvic stretch receptors

   The urge to push is the Ferguson reflex: pressure of the presenting part on stretch receptors of the pelvic floor triggers oxytocin release and bearing-down efforts.

Firm, steady force from a fist or the heel of the hand against the lower back during contractions, used to ease back labor, is called

1. transcutaneous nerve stimulation

   Transcutaneous nerve stimulation delivers mild electrical current through skin electrodes, not manual pressure.
2. counterpressure

   Counterpressure is steady pressure with a fist or the heel of the hand against the lower back during contractions, used to ease back labor.
3. double hip squeeze

   The double hip squeeze presses on both hips toward the midline, not on the back.

During controlled cord traction in the third stage, the provider's other hand presses upward just above the symphysis pubis. The main purpose of that hand is to prevent

1. uterine inversion

   Pressing upward just above the symphysis while the cord is pulled holds the fundus in place, which prevents uterine inversion.
2. retained cotyledons

   Retained cotyledons are found by inspecting the delivered placenta; the hand above the symphysis does not keep them from tearing off.
3. cervical laceration

   Cervical laceration comes from rapid dilation or instrumental birth, not from cord traction.

A patient reports strong rectal pressure and an urge to have a bowel movement. The cervix is 10 cm dilated and the vertex is at +2 station. The nurse should

1. recheck the cervix in 1 hour

   Rechecking the cervix in 1 hour delays care for a patient already completely dilated with the head low in the pelvis.
2. walk the patient to the bathroom

   Walking the patient to the bathroom risks an unplanned birth on the toilet at +2 station.
3. support pushing and prepare for birth

   Complete dilation with the vertex at +2 means the second stage is under way, so the nurse supports pushing and prepares for birth.

Immediately after the fetal head is born by extension, the next cardinal movement is

1. restitution

   After the head is born by extension, it untwists to line up with the shoulders again: restitution, followed by external rotation.
2. expulsion

   Expulsion is the last movement, the birth of the shoulders and body after external rotation.
3. internal rotation

   Internal rotation happens before extension, as the occiput turns toward the symphysis inside the pelvis.

After a vaginal birth, the nurse weighs all blood-soaked pads and linens at 850 g; their combined dry weight is 250 g. The quantitative blood loss is

1. 600 mL

   Quantitative blood loss is wet weight minus dry weight: 850 g − 250 g = 600 g, and 1 g of blood is counted as 1 mL.
2. 850 mL

   850 mL forgets to subtract the dry weight of the pads and linens.
3. 1,100 mL

   1,100 mL adds the dry weight instead of subtracting it.

During the admission exam of a term neonate, which finding should the nurse report to the provider?

1. White papules across the nose

   White papules across the nose are milia, blocked sebaceous glands that clear without treatment.
2. Blue-gray sacral patches

   Blue-gray sacral patches are congenital dermal melanocytosis, a benign finding that is documented, not escalated.
3. Two vessels in the umbilical cord

   Two vessels in the umbilical cord mean a single umbilical artery, which is linked with renal and cardiac anomalies and is reported for evaluation.

After an uncomplicated epidural placed more than 12 hours earlier, the earliest that a prophylactic dose of low-molecular-weight heparin can be given is

1. 4 hours after catheter removal

   For prophylactic dosing, low-molecular-weight heparin can be given 4 hours after the epidural catheter is removed, as long as 12 hours have passed since placement.
2. 24 hours after catheter removal

   Waiting 24 hours after catheter removal delays prophylaxis without need; 24-hour intervals apply to higher, therapeutic dosing around neuraxial placement.
3. after hospital discharge

   Starting only after hospital discharge leaves the patient unprotected during the highest-risk days after birth.

A patient with asthma and chronic hypertension has persistent uterine atony despite an oxytocin infusion. The most appropriate additional uterotonic is

1. methylergonovine 0.2 mg IM

   Methylergonovine 0.2 mg IM constricts blood vessels and is contraindicated with hypertension.
2. misoprostol 800 mcg sublingually

   Misoprostol 800 mcg sublingually is a prostaglandin E1 uterotonic that is safe with both asthma and hypertension.
3. dinoprostone 10 mg insert

   The dinoprostone 10 mg insert releases drug slowly for cervical ripening and is not used to treat atony.

At 1 minute after birth, a neonate has a heart rate of 110, a weak cry with slow, irregular breathing, some flexion of the extremities, a grimace to suctioning, and a pink body with blue hands and feet. The Apgar score is

1. 4

   A score of 4 drops two points: it scores the slow, irregular breathing with a weak cry 0 and the acrocyanosis 0, but each scores 1.
2. 5

   A score of 5 gives 0 for color, but a pink body with blue hands and feet (acrocyanosis) scores 1; 0 is for a pale or blue body.
3. 6

   Heart rate 110 scores 2; slow, irregular breathing with a weak cry 1; some flexion 1; grimace 1; pink body with blue hands and feet 1 — a total of 6.

After a vaginal birth, the newborn goes skin-to-skin with the birthing person right away. Matching identification bands for the two of them should be applied

1. after the first bath and full newborn assessment

   Waiting until after the first bath and full newborn assessment leaves hours in which an unlabeled newborn can be separated from the parent.
2. before parent and newborn are separated

   Matching bands go on in the birth room before the newborn and parent are ever apart, which closes the window in which a newborn could be mixed up with another infant or taken.
3. when the newborn is admitted to the nursery

   Waiting for nursery admission leaves the newborn unlabeled during the transfer, when mix-ups are most likely, and many newborns room in and never go to a nursery.