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 newborn appears jaundiced at 18 hours of age. What does this suggest?

  1. ANormal physiological jaundice that needs no further action
  2. BBreast milk jaundice
  3. CA normal effect of vitamin K
  4. DPathological jaundice that needs prompt assessment
2.Maternity & obstetric nursingHard

One hour after birth, the large baby of a mother with diabetes is jittery and feeding poorly. What should the nurse do first?

  1. AWrap the baby tightly and recheck in 4 hours
  2. BReassure the parents that jitteriness is normal
  3. CCheck the baby's blood glucose
  4. DGive a bath to wake the baby up
3.Dosage calculationsMedium
25 kg30 mg/kg/day4× per dayD = ? mg

A patient weighs 25 kg. The prescribed dose is 30 mg/kg per day, given in 4 equal doses. How many milligrams D are given per dose?

25 kg30 mg/kg/day4× per day
D = mg
4.Dosage calculationsHard
86 kg174 cmBSA = √(h·w/3600)250 mg/m²D = ? mg

A patient is 174 cm tall and weighs 86 kg. The prescription is 250 mg/m². Using the Mosteller formula BSA = √(height (cm) × weight (kg)/3600), find the dose D in mg.

174 cm86 kg250 mg/m²
D = mg
5.IV infusion ratesMedium
990 mLleft? mL/h8 h left

1000 mL was ordered over 10 hours. After 2 hours you find that 990 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?

1000 mL / 10 hafter 2 h: 990 mL
R = mL/h
6.IV infusion ratesHard
400 mg100 mL5 mL/h? mg/h

A bag contains 400 mg of a drug in 100 mL and runs at 5 mL/h. How many milligrams per hour D does the patient receive?

400 mg/100 mL5 mL/h
D = mg/h

3Solutions

1.Maternity & obstetric nursing

Answer: D · Pathological jaundice that needs prompt assessment

Why this is the answer

Physiological jaundice usually appears after 24 hours. Jaundice in the first 24 hours suggests haemolysis (for example blood group incompatibility) or infection and needs a bilirubin level and medical review.

Answer

D · Pathological jaundice that needs prompt assessment
2.Maternity & obstetric nursing

Answer: C · Check the baby's blood glucose

Why this is the answer

Jitteriness and poor feeding in a high-risk newborn suggest hypoglycaemia. A point-of-care glucose check guides treatment, such as feeding or glucose gel per protocol, with escalation if the level stays low.

Answer

C · Check the baby's blood glucose
3.Dosage calculations

Answer: D = 187.5 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

30·25 = 750 mg

Per dose

D = 750/4 = 187.5 mg

Answer

D = 187.5 mg
4.Dosage calculations

Answer: D = 509.7 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).

Body surface area

BSA = √(174·86/3600) = √4.157 = 2.039 m²

Dose

D = 250·2.039 = 509.7 mg

Answer

D = 509.7 mg
5.IV infusion rates

Answer: R = 123.8 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

1000/10 = 100 mL/h

New rate

R = 990/8 = 123.8 mL/h

Answer

R = 123.8 mL/h

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

6.IV infusion rates

Answer: D = 20 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

400/100 = 4 mg/mL

Dose rate

D = 4·5 = 20 mg/h

Answer

D = 20 mg/h

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