If you have type-1 diabetes, expect your insulin needs to change dramatically through the course of your pregnancy. The proportion of “basal” (background) to “bolus” (mealtime) insulin does not change much, but the total amount of insulin required goes through a complete metamorphosis. Do the doses simply rise or fall steadily throughout pregnancy? Of course not! This is diabetes we’re talking about. Nothing is simple.
For most women, insulin needs during pregnancy follow a pattern similar to a log flume ride found at an amusement park. Let me explain.
Weeks 0-6: Business as usual.
You’re just waiting in line to get on the log flume ride, totally oblivious to what you’re in for.
You probably don’t even know you’re pregnant, and insulin needs are no different than what they were before you conceived.
Weeks 6-10: The slight dip.
In log flume terms, this is like when you first get into the log boat, and the added weight makes it sink slightly. This phase is an amazing time: You’ve just found out that you’re pregnant, and you’re quite excited. As the embryo evolves into a fetus, the autoimmune process that has been beating down your pancreas all these years starts to ease up. This allows your pancreas to start secreting a bit of insulin on its own. The result: a reduction in the need for exogenous (pumped or injected) insulin. Low blood sugar is common during this phase, as many women are taken by surprise that they are producing some of their own insulin again. Temporary reductions to both basal and bolus insulin are usually necessary to prevent frequent bouts of hypoglycemia. A 25% reduction in insulin requirements is not uncommon.
Weeks 10-36: The steady climb.
This is the part of the log flume ride when you get on that long, slow conveyer belt up to the top. You know what happens to your body and the baby during this phase: growth, growth and more growth. Well, the same things happens to your insulin needs… despite the fact that your pancreas continues to produce small amounts of insulin. This is due to the increase in your body size as well as the hormones produced by the placenta which cause insulin resistance. It is necessary to make steady, gradual increases to both basal and bolus insulin in order to keep up with the increased needs. At our practice, we perform detailed reviews of blood sugar records weekly and make necessary adjustments. It is not unusual to see total insulin needs double or even triple from preconception until the end of the third trimester. Of course, gaining excess weight during pregnancy will require even greater increases to insulin doses, so proper nutrition and physical activity are as important as ever.
Weeks 36 to Delivery: The moment of calm.
After the conveyer belt has brought you to the top, this is the relaxing, scenic ride before the “big moment”. For a few weeks prior to delivery, insulin requirements level off. Things are in a “steady state” as you make your last-minute preparations.
Delivery: The big plunge
This is what made the log flume famous. Whether vaginal or via c-section, insulin needs come down quickly during delivery. If you deliver naturally, labor involves a great deal of… well… labor. And that means reduced insulin needs, as if you were running or lifting weights. And with any form of delivery, the removal of the placenta means a sharp dropoff in hormones that were causing insulin resistance. For these reasons, we often have our clients reduce their basal and bolus insulin doses by 50% during delivery.
1-2 days postpartum: The Splash
When that log boat comes careening down, it doesn’t just ease comfortably into the pool of water at the bottom. It torpedoes into it with full force, soaking you and any unfortunate onlookers. Insulin needs do the same type of thing after delivery. They may actually drop below where they were at the beginning. Remember during the “slight dip” phase when we discussed how the pancreas is capable of secreting some insulin on its own? Well, that process continues until shortly after delivery. And when you combine a pancreas that is producing insulin with the sudden elimination of placental hormones, the results can be astonishing. For the first 24-48 hours postpartum, don’t be surprised if insulin needs are dramatically reduced. A small percentage of women don’t need to take any insulin during this phase! After delivery, we generally have our clients return to their pre-pregnancy doses, but if any lows occur, we won’t hesitate to make major reductions.
It was a wild and crazy ride, but worth it in the end. Just as the log boat makes its way back to the starting point, insulin needs also find their way back to their pre-pregnancy levels. That’s not to say that there won’t be any special adjustments necessary. Nursing will usually reduce insulin needs; retained weight will increase them; and new sleep patterns may require changes to basal insulin levels. Not exactly a series of log flume rides, but a ride that truly never ends!