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

Which statement about the lactational amenorrhoea method (LAM) is correct?

  1. AIt works for as long as the mother breastfeeds at all
  2. BIt needs full breastfeeding, no periods and a baby under 6 months
  3. CIt is reliable even when the baby is formula-fed at night
  4. DIt becomes more reliable after the periods return
2.Maternity & obstetric nursingHard

At 7 weeks of pregnancy, a woman reports sudden severe pain on one side of the lower abdomen, pain in the shoulder tip and dizziness. What should the nurse suspect?

  1. ANormal round ligament pain caused by the growing uterus
  2. BA ruptured ectopic pregnancy with internal bleeding
  3. CBraxton Hicks contractions
  4. DHyperemesis gravidarum
3.Dosage calculationsMedium
25 kg20 mg/kg/day3× per dayD = ? mg

A patient weighs 25 kg. The prescribed dose is 20 mg/kg per day, given in 3 equal doses. How many milligrams D are given per dose?

25 kg20 mg/kg/day3× per day
D = mg
4.Dosage calculationsHard
00.10.20.30.40.50.60.70.80.911 mL

The prescription is 3050 units of a drug that comes as 5000 units/mL. Draw up the dose in the 1 mL syringe: what volume V do you give?

3050 units5000 units/mL
V = mL
5.IV infusion ratesMedium
V = ?15 gtt/mL40 gtt/min8 h

A drip runs at 40 gtt/min through a set of 15 gtt/mL. How many millilitres V does the patient receive in 8 hours?

40 gtt/min15 gtt/mL8 h
V = mL
6.IV infusion ratesHard
160 mLleft? mL/h3 h left

500 mL was ordered over 10 hours. After 7 hours you find that 160 mL is still in the bag, and the order must still finish on time. By what percentage Δ must the original pump rate be increased?

500 mL / 10 hafter 7 h: 160 mL
Δ = %

3Solutions

1.Maternity & obstetric nursing

Answer: B · It needs full breastfeeding, no periods and a baby under 6 months

Why this is the answer

LAM is effective only if the mother is fully or nearly fully breastfeeding day and night, her periods have not returned and the baby is under 6 months. Ovulation can occur before the first period.

Answer

B · It needs full breastfeeding, no periods and a baby under 6 months
2.Maternity & obstetric nursing

Answer: B · A ruptured ectopic pregnancy with internal bleeding

Why this is the answer

One-sided pain, shoulder-tip pain and dizziness early in pregnancy suggest a ruptured ectopic pregnancy. It is an emergency: monitor vital signs, obtain IV access and get urgent medical help.

Answer

B · A ruptured ectopic pregnancy with internal bleeding
3.Dosage calculations

Answer: D = 166.7 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

20·25 = 500 mg

Per dose

D = 500/3 = 166.7 mg

Answer

D = 166.7 mg
4.Dosage calculations

Answer: V = 0.61 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 = 3050/5000 = 0.61 mL

On the syringe

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

Answer

V = 0.61 mL
5.IV infusion rates

Answer: V = 1280 mL

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.

Rate in mL/h

40·60/15 = 160 mL/h

Volume

V = 160·8 = 1280 mL

Answer

V = 1280 mL
6.IV infusion rates

Answer: Δ = 6.667 %

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

500/10 = 50 mL/h

New rate

R = 160/3 = 53.33 mL/h

Percentage change

Δ = (53.33 − 50)/50·100% = 6.667%

Answer

Δ = 6.667%

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

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