Calculation of Initial Insulin Pump Requirements in Pregnancy
Two pregnancy-oriented approaches: AACE pregnancy protocol and Sweet Success three-rate schedule. Both include TDD plus quick estimates for ISF (1800 rule) and ICR (300/400 rules). BETA TESTING
Successful blood sugar control using an insulin pump requires good record-keeping. Candidates should be willing to check their blood glucose levels—ideally fasting blood sugar levels. before and after meals as well as record the timing of their meals. In addition, candidates should be able to troubleshoot problems related to pump operation and be willing to maintain frequent contact with members of the health care team.
Day before pump start:
- Instruct patient to discontinue use of long-acting insulin (NPH, Lantus).
- They should continue injecting rapid acting or regular insulin before meals.
- Instruct the patient to eat breakfast and inject rapid insulin or regular as usual.
- If the patient's total daily dose (TDD) is uncertain you may use the Initial Insulin Dose Calculator to get a rough estimate of their TDD.
AACE pregnancy protocol (Type 1 DM) — basal + meal bolus by gestation × kg
What this section calculates
- Basal total = (units × kg) × weight
- Meal bolus total = (units × kg) × weight; suggested per-meal = total ÷ 3
- AACE TDD (worksheet) = basal total + meal bolus total
- ISF ≈ 1800/TDD; ICR breakfast ≈ 300/TDD; ICR lunch/dinner ≈ 400/TDD
Basal total requirement
—U/day
Meal bolus total
—U/day
Suggested bolus before each meal (÷ 3)
—U
AACE TDD (basal + bolus total)
—U/day
ISF (1800 rule)
—mg/dL per 1U
ICR breakfast (300/TDD)
—g per 1U
ICR lunch/dinner (400/TDD)
—g per 1U
Basal delivered by schedule (check)
—U/day
AACE time-of-day basal schedule
Rates shown as U/hr
Enter inputs and click Calculate.
References (AACE / pump basics / ratios)
- Grunberger G, et al. Statement by the American Association of Clinical Endocrinologists Consensus Panel on insulin pump management. Endocr Pract. 2010;16(5):746–762. PMID: 21356638
- Kuroda A, Yasuda T, Takahara M, et al. Carbohydrate-to-insulin ratio is estimated from 300–400 divided by total daily insulin dose in type 1 diabetes patients who use the insulin pump. Diabetes Technol Ther. 2012;14(11):1077–1080. doi:10.1089/dia.2012.0109. PMID: 23101953
- Walsh J. Pumping Everything for Success on an Insulin Pump. San Diego, CA: Torrey Pines Press; 2016.
Sweet Success basal schedule (three basal rates)
- #1 basal rate (j) = h × 0.8. Used 12 AM → 4 AM.
- #2 basal rate (i) = h × 1.2. Used 4 AM → 9 AM.
- #3 basal rate (h) = total daily pump basal ÷ 24 (U/hr). Used 9 AM → 12 AM.
Basal total used
—U/day
12 AM → 4 AM (j)
—U/hr
4 AM → 9 AM (i)
—U/hr
9 AM → 12 AM (h)
—U/hr
Basal delivered by schedule (check)
—U/day
Difference vs basal total
—U/day
TDD used for ISF/ICR
—U/day
ISF (1800 rule)
—mg/dL per 1U
ICR breakfast (300/TDD)
—g per 1U
ICR lunch/dinner (400/TDD)
—g per 1U
Sweet Success time-of-day basal schedule
Rates shown as U/hr
Choose an input mode and calculate.
References (Sweet Success / ratios)
- California Diabetes and Pregnancy Program (CDAPP) Sweet Success. Guidelines for Care. Revised edition July 2012. PDF
- Kuroda A, Yasuda T, Takahara M, et al. Diabetes Technol Ther. 2012;14(11):1077–1080. PMID: 23101953
- Walsh J. Pumping Everything for Success on an Insulin Pump. San Diego, CA: Torrey Pines Press; 2016.
Testing new basal rates and making adjustments (practical workflow)
Big picture
- Basal testing asks: “If I remove food and bolus variables, does glucose stay reasonably steady?”
- Many pump teaching materials suggest testing when the patient has had a stable prior day (no illness, unusual exercise, major highs/lows) and starting the test in a safe range.
- Pregnancy is different: tighter targets and lower hypoglycemia tolerance → use extra caution and coordinate with your diabetes-in-pregnancy team.
How to do a basal test (step-by-step)
- Pick a “quiet” day: Avoid illness and unusual exercise/stress; make sure the infusion site is working and supplies are available.
- Separate basal from bolus: Wait ~4 hours after the last meal/snack and bolus; avoid very high-fat meals beforehand if delayed rises are common.
- Start in a safe range: If glucose is low, treat and stop; if very high, correct and postpone.
- Avoid confounders: During the test window, avoid carbs and avoid correction boluses unless safety requires stopping.
- Check frequently: Overnight commonly every 2–3 hours; daytime often every 1–2 hours during the chosen window.
- Stop rules: If hypoglycemia occurs, treat and stop; if above your clinic’s “too high” threshold, stop and correct per plan.
Example testing plan (split into “parts of the day”)
A common approach is to test one time-block per day rather than multiple blocks at once:
- Overnight (after dinner bolus is out of action)
- The overnight basal rate is adjusted by checking the blood sugar at 12 AM, 3 AM and 7AM.
- Morning → lunch
- Lunch → dinner
- Dinner → bedtime
Many toolkits emphasize adjusting basal settings first, then refining ISF and ICR.
How to interpret results and adjust basal rates (pregnancy-aware)
- Look for a pattern (not a single reading): repeat a similar test on 2–3 comparable days if feasible.
- Signals that basal may be off: many teaching materials use a rise or fall of ~30–40 mg/dL across the time block (assuming no carbs/bolus confounders).
If the glucose level increases by more than 30 mg/dL above the
targeted range, the basal rate should be increased.
If the
glucose level decreases by more than 30 mg/dL (or falls below
target) between readings, treat the low blood sugar and decrease the
basal rate .
- Change size: If the glucose level a typical starting adjustment is ~10–20% for that segment (or a small absolute change, e.g., 0.05–0.2 U/hr depending on baseline rate and clinical context).
- Timing: adjust the basal segment ~2 hours before the observed rise/fall (lead time depends on insulin action and profile).
- Safety first: if lows occur, prioritize reducing basal and address contributing factors (activity, site issues, stacked boluses, nausea/poor intake).
- Order of operations: many pump references recommend tuning basal first, then ISF, then ICR.
Basal testing references
- Kaiser Permanente Northern California. Guidelines for Basal Rate Checking (PDF). Open PDF
- Texas Department of State Health Services (TxDSHS). Insulin Pump Therapy (PDF toolkit). Open PDF
- Medtronic Pumping Protocol A Guide to Insulin Pump Therapy Initiation . Bode W , Bruce Atlanta Diabetes Association Atlanta Georgia Medtronic
- Insulin Pump Therapy: Guidelines for Successful Outcomes American Association of Diabetes Educators 2008 Consensus Summit September 18, 2008 • Chicago, Illinois The American Association of Diabetes Educators http://www.diabeteseducator.org/export/sites/aade/_resources/pdf/Insulin_Pump_White_Paper.pdf
- Walsh J. Pumping Everything for Success on an Insulin Pump. San Diego, CA: Torrey Pines Press; 2016.
Disclaimer
Educational clinician tool. Not a substitute for individualized medical care, device training, or manufacturer labeling. Confirm all settings before use.