Lantus Dosing in Pregnancy
Insulin glargine (Lantus) can be used in pregnancy with frequent dose titration, typically starting at pre-pregnancy doses and increasing by approximately 5% per week after 16 weeks gestation, with total daily insulin requirements often doubling to tripling by the third trimester. 1
Initial Dosing Strategy
For pregnant women already on Lantus pre-conception, continue the current dose initially, recognizing that requirements will change dramatically throughout pregnancy. 1 The first trimester often brings decreased insulin requirements and increased hypoglycemia risk due to enhanced insulin sensitivity, so dose reductions may be necessary. 2, 1
Titration Schedule Throughout Pregnancy
- After 16 weeks gestation, insulin resistance increases exponentially, requiring weekly or biweekly dose increases of approximately 5% per week through week 36. 1
- By late gestation, expect total daily insulin requirements to double or triple compared to pre-pregnancy doses. 1
- Monitor fasting and postprandial glucose 4-6 times daily to guide dose adjustments. 1
Target Glucose Levels for Dose Adjustment
Titrate Lantus to achieve these targets 2:
- Fasting glucose: 70-95 mg/dL (3.9-5.3 mmol/L)
- One-hour postprandial: 110-140 mg/dL (6.1-7.8 mmol/L)
- Two-hour postprandial: 100-120 mg/dL (5.6-6.7 mmol/L)
Important Dosing Considerations
Lantus should comprise a smaller proportion of total daily insulin in pregnancy, with greater emphasis on prandial insulin coverage. 2 This differs from non-pregnant management due to the postprandial hyperglycemia characteristic of pregnancy physiology.
Alternative Basal Insulin Option
If transitioning from pump therapy or requiring subcutaneous basal insulin, the 24-hour basal dose can be replaced with Lantus given in two divided doses 12 hours apart (e.g., if total daily basal is 22 units, give 11 units every 12 hours). 2 This allows easier transition back to other regimens if needed.
Monitoring and Safety
- Evaluate insulin requirements every 2-3 weeks as pregnancy progresses. 1
- A rapid reduction in insulin requirements may indicate placental insufficiency and requires immediate medical evaluation. 1
- Educate patients and family about hypoglycemia prevention, recognition, and treatment, as pregnancy alters counterregulatory responses. 1
Post-Delivery Dose Adjustment
Immediately after placental delivery, insulin requirements drop precipitously. 1 Resume basal insulin at either 80% of pre-pregnancy doses or 50% of end-of-pregnancy doses. 1
Critical Caveats
- Insulin glargine is FDA pregnancy category C (unlike most other insulins which are category B), though observational studies suggest comparable safety to NPH insulin. 2, 3
- Due to the complexity of insulin management in pregnancy, referral to a specialized diabetes and pregnancy center is strongly recommended. 2, 1
- Pregnancy is a ketogenic state; women are at risk for diabetic ketoacidosis at lower glucose levels than when not pregnant. 1
- Do not mix Lantus with short-acting insulins in the same syringe, as it may coprecipitate. 4