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

Why is tight glucose control before conception important in women with pre-existing diabetes?

  1. AIt prevents the need for any monitoring during pregnancy
  2. BEarly hyperglycaemia raises the risk of birth defects
  3. CIt guarantees that the baby will be born at term
  4. DIt prevents the mother from developing pre-eclampsia
2.Maternity & obstetric nursingHard

The nurse must deliver a baby before the provider arrives. As the head crowns, what should the nurse do?

  1. APush the head back to delay the birth
  2. BAsk the woman to cross her legs tightly until help comes
  3. CPull firmly on the head to speed the birth
  4. DApply gentle pressure to the head to slow the birth
3.Dosage calculationsMedium
22 kg30 mg/kgD = ? mg

A patient weighs 22 kg and is prescribed 30 mg/kg as a single dose. Find the dose D in mg.

22 kg30 mg/kg
D = mg
4.Dosage calculationsHard
50%stockwater = ? mL

You must prepare 500 mL of a 2.5% (w/v) solution from a 50% (w/v) stock solution. How much water W must be added to the stock?

C₁ = 50%C₂ = 2.5%V₂ = 500 mL
W = mL
5.IV infusion ratesMedium
500 mL10 gtt/mL10 h? gtt/min

Infuse 500 mL over 10 hours with a giving set of 10 gtt/mL. Find the drip rate R in drops per minute. Round to the nearest whole number.

500 mL10 h10 gtt/mL
R = gtt/min
6.IV infusion ratesHard
500 mg100 mL30 mL/h? mg/h

A bag contains 500 mg of a drug in 100 mL and runs at 30 mL/h. How many milligrams per hour D does the patient receive?

500 mg/100 mL30 mL/h
D = mg/h

3Solutions

1.Maternity & obstetric nursing

Answer: B · Early hyperglycaemia raises the risk of birth defects

Why this is the answer

Hyperglycaemia during organogenesis increases the risk of heart, neural tube and other anomalies and of miscarriage. Good preconception control and high-dose folic acid lower this risk.

Answer

B · Early hyperglycaemia raises the risk of birth defects
2.Maternity & obstetric nursing

Answer: D · Apply gentle pressure to the head to slow the birth

Why this is the answer

Gentle pressure on the fetal head, with the woman panting, slows birth and reduces perineal tearing and rapid pressure changes in the fetal skull. The nurse then checks for a nuchal cord and supports the baby's body.

Answer

D · Apply gentle pressure to the head to slow the birth
3.Dosage calculations

Answer: D = 660 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.

Dose

30·22 = 660 mg

Answer

D = 660 mg
4.Dosage calculations

Answer: W = 475 mL

Solution strengths: a percentage strength is grams per 100 mL, so 1% = 1 g/100 mL = 10 mg/mL. A ratio strength 1:1000 means 1 g in 1000 mL = 1 mg/mL; 1:10 000 is 0.1 mg/mL. For a dilution the amount of drug stays the same: C₁·V₁ = C₂·V₂.

Volume of stock

V₁ = 2.5·500/50 = 25 mL

Water to add

W = 500 − 25 = 475 mL

Answer

W = 475 mL
5.IV infusion rates

Answer: R = 8 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

10·60 = 600 min

Drip rate

R = 500·10/600 = 8.333 ≈ 8 gtt/min

Answer

R = 8 gtt/min

At the bedside you round to the nearest whole drop: 8 gtt/min.

6.IV infusion rates

Answer: D = 150 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 = 5·30 = 150 mg/h

Answer

D = 150 mg/h

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