With pregnancy, many body changes are happening all at once. And for those living with type 1 diabetes (T1D), this affects day-to-day management decisions. Ideally, a healthy pregnancy with T1D starts in the planning stages. This way, you can feel more assured, knowing you’re taking the steps to support a positive pregnancy experience.  

As a pregnant person living with T1D, there’s a lot to consider each and every day. Understanding what’s normal, when to seek support, and how to manage T1D is a lot to think through. That’s why it’s common to have so many questions!  

Here, you’ll find the answers to questions most frequently asked.  

 

1. Is it normal for insulin needs to increase during pregnancy?

Yes. For most people living with T1D, insulin needs will double or even triple throughout pregnancy. Some people’s insulin needs may be even greater.  This is normal and expected. 

During pregnancy, you’ll strive to meet lower hemoglobin A1C and time in range targets, which alone can lead to higher insulin intake early on.  

In the first trimester, there is more insulin sensitivity. This means your insulin needs may drop slightly, and you may be at higher risk of hypoglycemia (low blood glucose).  

In the second and third trimesters, there is more insulin resistance. This means your insulin needs will increase, and you may be at higher risk for hyperglycemia (high blood sugar).   

Your diabetes care team will help to support and guide necessary changes to your diabetes management plan from preconception to postpartum. 

 

2. What is U-200 insulin, and is it safe for pregnancy?

You’re likely more familiar with U-100 insulin, which is the most commonly prescribed strength. This type of insulin contains 100 units per ml.  

However, when someone uses larger amounts of insulin, such as in pregnancy, a provider may prescribe U-200 insulin. This type of insulin is twice as strong as U-100, containing 200 units per ml.   

The U-200 insulin versions are considered equally safe as U-100 versions and have been used by many people in pregnancy without known safety concerns. 

 

U-200 is available as a rapid-acting insulin: lispro (Humalog) and lispro-aabc (Lymjev) 

  • These work the same as the U-100 versions 
  • The pen is larger, holding 900 units, so it lasts longer  
  • Only 60 units can be injected at one time, and the smaller volume may feel more comfortable. 

 

 U-200 is available as a long-acting insulin: degludec (Tresiba) 

  • This works the same as the U-100 version 
  • The pen is larger, holding 900 units, so it will last longer 
  • Up to 160 units can be given at one time (compared to 80 units with most traditional U-100 pens) 

 

3. Is U-200 insulin safe to use in an insulin pump? 

The simple answer is yes. However, there are some additional safety risks to consider.  

Insulin pumps are frequently used in pregnancy and usually hold about 200 to 300 units of insulin. As insulin needs increase during pregnancy, people tend to reload insulin more frequently. By using U-200 lispro, you can decrease this frequency. 

In other words, using more concentrated insulin can help keep your pump changes closer to your usual pre-pregnancy routine. While using insulin lispro U-200 insulin in a pump can make good sense, there are important things to consider.  

To begin with, all insulin pumps are programmed to work with U-100 insulin, not U-200.  

So, if you switch to U-200 insulin, you’ll have to manually adjust pump settings because, again, it’s twice as strong as U-100 insulin. This includes adjusting basal rates, carbohydrate ratios, and correction factors with the support of your care team. 

Moreover, U-200 insulin is only available in a pen. This being the case, insulin must be drawn out of the pen for use in an insulin pump. While this shouldn’t be difficult to do, if you try to give an injection with the pen later, it may not give an accurate dose. That’s because air may have entered the pen. 

As long as these safety concerns are accounted for, then U-200 can be an option in an insulin pump to allow for less frequent set changes. 

 

4. How does pregnancy affect insulin resistance, and is there a medication to help?

Insulin resistance increases during the second and third trimesters of pregnancy.  

Taking medications such as SGLT2 inhibitors or GLP-1 receptor agonists is not recommended to help with pregnancy-related insulin resistance. 

While metformin can help with insulin resistance, its use in pregnancy isn’t clear-cut. Using metformin should be based on shared decision-making with you and your healthcare team.  

Here’s why: 

  • Metformin crosses the placenta in the second and third trimesters 
  • There are no high-quality, randomized, controlled trials on its use in pregnancy with T1D  
  • Research on metformin use in pregnancies with type 2 diabetes and gestational diabetes has shown safety for babies and parents. However, it’s thought that metformin use in pregnancy can result in childhood overweight and obesity years later. While some studies support that line of thought, others do not. More research is needed. 

 

5. Can increased insulin affect my baby’s birth size?

The amount of insulin you take will not affect the size of your baby. Why? Injected insulin does not cross the placental barrier. 

Hyperglycemia is the number one risk factor for having a larger baby.  

That’s because extra blood sugar does cross through the placenta. In turn, the baby produces more insulin, which may increase their birth size and place them at greater risk for hypoglycemia at birth. 

To put it another way, meeting your glucose target goals is incredibly important to your baby’s overall health. Increasing insulin needs during pregnancy is normal, and changes to insulin management are necessary to meet these goals. 

 

6. How often will I need to adjust my insulin ratios during pregnancy? 

For most people, insulin needs increase by 5% each week in the second and third trimesters. That said, this may be different for different people. 

Oftentimes, bolus insulin will need to be increased more than the basal insulin. Again, there can be variability in how much change is needed and when.  

Reviewing your diabetes data and adjusting settings every week as needed is recommended. This may include changes to carbohydrate ratios, correction factors, and basal insulin.  

Frequent appointments and touchpoints with your care team will help to set you up for success. 

 

7. Can I wear a CGM on my belly for my entire pregnancy?

Some people find a CGM to be more comfortable or work better when it’s worn on the stomach during pregnancy. 

While you can continue to use your belly, Dexcom G7, Libre 2, and Libre 3 are only FDA-approved for use on the upper arm in pregnancy. 

If you’re using your belly, place the CGM on the sides of your abdomen and further away from your belly button, where you can pinch a little skin. Wearing your CGM on your upper arm as delivery approaches is best. Then, it’ll be out of the way for fetal monitoring — and in case of an unplanned cesarean section.  

 

 8. Can I use “auto mode” on my insulin pump throughout my pregnancy? 

That depends. 

CamAPS is the only FDA-approved algorithm for “auto mode” use. While this has been tested in pregnancy and has targets to 80mg/dL (meeting pregnancy time in range goals of at least 70% between 63-140mg/dL), it’s not available in the U.S.   

Medtronic MiniMed™ 780G has targets to 100mg/dL. The CRISTAL Trial showed comparable time in range results with those not using auto mode and “a little more” time in range when using 780G overnight.  

Of note, many people exaggerate carbohydrate totals to help decrease their glucose levels.  

Tidepool Loop will be available soon with Sequel’s twiist™ AID system, which has targets to 87mg/dL. However, it has not been studied for use in pregnancy.  

In general, pregnancy targets are challenging to meet with standard insulin pumps or multiple daily injections. That’s why many choose to use auto mode and adjust settings frequently to help reach pregnancy targets.  

Some people choose to use auto mode during the daytime and turn it off at night. With a fasting glucose goal of 95mg/dL, many of those who are pregnant and living with T1D find they’re limited by technology thresholds. 

 

9. Is it okay to wear my insulin pump during labor and delivery? 

This varies depending on the hospital and their protocols.  

Discussing this with your healthcare team before delivery is important so there are no surprises. If you are asked to remove your insulin pump, you’ll have an IV insulin infusion instead.  

If you have time, place your insulin pump site on your arm instead of your belly and pack extra supplies. Then, you’ll be set if you need to replace your insulin pump or CGM.  

 

10. When will my insulin needs return to what they were pre-pregnancy?

Most people will return to pre-pregnancy insulin needs, or even less, in the first 24 to 48 hours postpartum. Timing-wise, after the placenta is delivered, there’s a rapid increase in insulin sensitivity. 

And, if you’re breastfeeding, insulin needs may be even less. Chat with your care team beforehand so you have a plan for insulin dosing after delivery. 

 

In short 

Meeting your glucose target goals in pregnancy is incredibly important to your baby’s overall health. Increasing insulin needs during pregnancy are expected, and changes to insulin management are necessary to meet these targets.  

Your T1D pregnancy glucose goals will be shared and monitored by your diabetes care team. Meeting time in range targets is best accomplished through close communication with your healthcare providers.