Maternity Nursing: cram pack

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

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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 woman 1 day after birth has a blood pressure of 150/96 mmHg and a headache. She had normal blood pressures in pregnancy. What should the nurse do?

  1. AReassure her that this is normal after birth
  2. BGive paracetamol (acetaminophen) and ignore the blood pressure
  3. CReport it and assess for postpartum pre-eclampsia
  4. DEncourage her to walk to lower her blood pressure
2.Maternity & obstetric nursingHard

A woman at 29 weeks is in preterm labour and is given magnesium sulfate. What is the main reason for giving it at this gestation?

  1. ATo prevent eclamptic seizures
  2. BTo speed up fetal lung maturation
  3. CTo treat a urinary tract infection
  4. DTo reduce the baby's risk of cerebral palsy
3.Dosage calculationsMedium
60 kg25 mg/kg/day4× per dayD = ? mg

A patient weighs 60 kg. The prescribed dose is 25 mg/kg per day, given in 4 equal doses. How many milligrams D are given per dose?

60 kg25 mg/kg/day4× per day
D = mg
4.Dosage calculationsHard
00.10.20.30.40.50.60.70.80.911 mL

The prescription is 2500 units of a drug that comes as 10000 units/mL. Draw up the dose in the 1 mL syringe: what volume V do you give?

2500 units10000 units/mL
V = mL
5.IV infusion ratesMedium
1000 mL20 gtt/mL4 h? gtt/min

Infuse 1000 mL over 4 hours with a giving set of 20 gtt/mL. Find the drip rate R in drops per minute. Round to the nearest whole number.

1000 mL4 h20 gtt/mL
R = gtt/min
6.IV infusion ratesHard
500 mg100 mL8 mL/h? mg/h

A bag contains 500 mg of a drug in 100 mL and runs at 8 mL/h. How many milligrams per hour D does the patient receive?

500 mg/100 mL8 mL/h
D = mg/h

3Solutions

1.Maternity & obstetric nursing

Answer: C · Report it and assess for postpartum pre-eclampsia

Why this is the answer

New hypertension with a headache after birth can be postpartum pre-eclampsia, even with normal readings in pregnancy. The nurse reports it, checks urine protein and symptoms and follows the protocol.

Answer

C · Report it and assess for postpartum pre-eclampsia
2.Maternity & obstetric nursing

Answer: D · To reduce the baby's risk of cerebral palsy

Why this is the answer

Before about 32 weeks, magnesium sulfate given when preterm birth is imminent reduces the risk of cerebral palsy. It is a neuroprotective use, separate from seizure prevention in pre-eclampsia.

Answer

D · To reduce the baby's risk of cerebral palsy
3.Dosage calculations

Answer: D = 375 mg

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.

Total per day

25·60 = 1500 mg

Per dose

D = 1500/4 = 375 mg

Answer

D = 375 mg
4.Dosage calculations

Answer: V = 0.25 mL

Drawing up a dose: volume = (prescribed dose/stock strength) × stock volume. Convert to the same units first, then check that the volume fits the syringe and lands on one of its graduations.

Volume

V = 2500/10000 = 0.25 mL

On the syringe

On this 1 mL syringe every small line is 0.01 mL.

Answer

V = 0.25 mL
5.IV infusion rates

Answer: R = 83 gtt/min

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.

Time in minutes

4·60 = 240 min

Drip rate

R = 1000·20/240 = 83.33 ≈ 83 gtt/min

Answer

R = 83 gtt/min

At the bedside you round to the nearest whole drop: 83 gtt/min.

6.IV infusion rates

Answer: D = 40 mg/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.

Concentration

500/100 = 5 mg/mL

Dose rate

D = 5·8 = 40 mg/h

Answer

D = 40 mg/h

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