Maternity Nursing: cram pack

Formula sheets, the key method steps for every topic and 6 practice problems, with full solutions at the back.

New problemsBack to the course

In the print window, choose “Save as PDF” to keep a copy on your device.

1Formulas and methods

Maternity & obstetric nursing

Method

  1. Place the woman in time: weeks of pregnancy, stage of labour or day after birth, and decide what is normal at that point.
  2. Look for the patient in danger: the mother, the fetus or the newborn, or more than one of them.
  3. Link the finding to its cause: VEAL CHOP for decelerations, the four Ts for bleeding, BUBBLE-HE after birth.
  4. Choose the action that improves blood flow and oxygen first (side-lying, stopping oxytocin, fundal massage), then escalate.

Dosage calculations

Dose from strength
volume = dose / strength
Weight-based dose
dose = mg/kg × body weight
Tablets
number = dose / tablet strength
Units
1 g = 1000 mg, 1 mg = 1000 mcg

Method

  1. Convert the ordered dose and the stock strength to the same unit.
  2. Use desired over have times quantity: (D/H) × Q.
  3. For weight-based doses, multiply by the weight in kg first, then divide the daily dose by the number of doses.
  4. Estimate first and check that the answer is reasonable.

IV infusion rates

Pump rate
mL/h = volume (mL)/time (h)
Drip rate
drops/min = volume (mL) × drop factor / time (min)
Infusion time
time (h) = volume (mL)/rate (mL/h)

Method

  1. Pump rate in mL/h: volume divided by time in hours.
  2. Drip rate in drops/min: volume × drop factor divided by time in minutes.
  3. For time remaining: volume left divided by the rate.
  4. Round as the question or the equipment requires.

2Practice problems

1.Maternity & obstetric nursingMedium

A newborn at 42 weeks has dry, cracked, peeling skin, long nails and little vernix. How is this baby best described?

  1. ALarge for gestational age
  2. BPost-term (postmature)
  3. CPreterm
  4. DSmall for gestational age only
2.Maternity & obstetric nursingHard

After birth of the head, the nurse feels the umbilical cord loosely around the baby's neck. What is the appropriate action?

  1. AAsk the woman to stop pushing for 30 minutes
  2. BPush the baby's head back into the vagina
  3. CClamp and cut the cord before the shoulders deliver in every case
  4. DSlip the loop over the head or let the body deliver through it
3.Dosage calculationsMedium
84 kgBSA = 1.8 m²100 mg/m²D = ? mg

A patient weighing 84 kg has a body surface area of 1.8 m². The prescription is 100 mg/m². Find the dose D in mg.

84 kgBSA = 1.8 m²100 mg/m²
D = mg
4.Dosage calculationsHard
40k units500 mL? mL/h1200 units/h

An infusion contains 40000 units of a drug in 500 mL. The prescription is 1200 units per hour. At what rate R do you set the pump, in mL/h?

40000 units/500 mL1200 units/h
R = mL/h
5.IV infusion ratesMedium
800 mLleft? mL/h3 h left

1500 mL was ordered over 6 hours. After 3 hours you find that 800 mL is still in the bag, and the order must still finish on time. To what rate R in mL/h must the pump be reset?

1500 mL / 6 hafter 3 h: 800 mL
R = mL/h
6.IV infusion ratesHard
4 g1000 mL? mL/h1.5 mg/min

A bag contains 4 g of a drug in 1000 mL. The order is 1.5 mg per minute. At what rate R do you set the pump, in mL/h?

4 g/1000 mL1.5 mg/min
R = mL/h

3Solutions

1.Maternity & obstetric nursing

Answer: B · Post-term (postmature)

Why this is the answer

Post-term babies often have dry, peeling skin, long nails, little vernix and lanugo and an alert look. They may also have meconium staining and are at risk of hypoglycaemia.

Answer

B · Post-term (postmature)
2.Maternity & obstetric nursing

Answer: D · Slip the loop over the head or let the body deliver through it

Why this is the answer

A loose nuchal cord can usually be slipped over the head or the baby can be born through it (somersault manoeuvre). Clamping and cutting before birth is reserved for a tight cord that prevents delivery.

Answer

D · Slip the loop over the head or let the body deliver through it
3.Dosage calculations

Answer: D = 180 mg

Body-surface-area dosing: many cytotoxic and some paediatric doses are prescribed per square metre of body surface area: dose (mg) = dose per m² × BSA (m²). The Mosteller formula estimates BSA = √(height (cm) × weight (kg)/3600).

Dose

D = 100·1.8 = 180 mg

Answer

D = 180 mg
4.Dosage calculations

Answer: R = 15 mL/h

Dose calculation: the amount to give equals what is prescribed divided by what you have, times the quantity it comes in: amount = (desired dose/stock strength) × stock volume. Always keep the units the same (convert g to mg, mg to mcg first) and check that the answer is sensible.

Concentration

40000/500 = 80 units/mL

Pump rate

R = 1200/80 = 15 mL/h

Answer

R = 15 mL/h
5.IV infusion rates

Answer: R = 266.7 mL/h

Infusion rates: a pump is set in mL/h = volume/time in hours. A gravity drip is counted in drops per minute: gtt/min = volume (mL) × drop factor (gtt/mL)/time (min). The drop factor is printed on the tubing package: macrodrip sets deliver 10, 15 or 20 gtt/mL (blood sets often 10 gtt/mL in the US, 15 in the UK) and microdrip sets 60 gtt/mL. Always use the drop factor the question or package gives.

Original rate

1500/6 = 250 mL/h

New rate

R = 800/3 = 266.7 mL/h

Answer

R = 266.7 mL/h

Many hospitals allow such an adjustment up to 25% without a new order; check local policy.

6.IV infusion rates

Answer: R = 22.5 mL/h

Dose-based infusions: concentration = amount of drug in the bag/bag volume. Pump rate (mL/h) = dose per hour/concentration, and dose per hour = mL/h × concentration. Convert per-minute doses to per-hour (× 60) and keep the mass units the same (1 g = 1000 mg, 1 mg = 1000 mcg).

Concentration

4000 mg/1000 mL = 4 mg/mL

Dose per hour

1.5·60 = 90 mg/h

Pump rate

R = 90/4 = 22.5 mL/h

Answer

R = 22.5 mL/h

ExamProblems · examproblems.com/courses/maternity-nursing