This pregnancy, when my blood sugars spiked around 34 weeks, indicating increased insulin needs, neither my endocrinologist nor I responded with the dramatic changes necessary to counter them. That resulted in 7-10 days of high (150-200) 2-hour post-meal blood sugars that made me EXTREMELY uncomfortable (not physically, but psychologically). As a result of my anxiety, I ate very little and very infrequently, fearing that would only prolong the high blood sugar.
This instability in my BGs was the background for a massive migraine I experienced over the course of 5 days during my 35th week. I was unable to drink anything that didn't come back up for about 18 hours, and unable (and afraid) to eat anything for about 36 hours. The headache lingered for several days after I resumed mostly normal functioning. My doctor helped me rule out meningitis, preeclampsia/toxemia, and a brain aneurysm (yeah, I freaked out a little bit), showed me an acupunture pressure point on my palms to help relieve the pain, and recommended Tylenol.
My suspicion is that the high blood sugars and the headache were related, somehow. I think that the headache may have been the result of poor nutrition for the 7-10 days prior. I wasn't eating enough because I was afraid of high blood sugars, but I happened to be restricting my food intake at the very same time that my baby and my body were requiring extra amounts of food to support the baby's growth, an increase in amniotic fluid and blood volume, and so forth. My OB had mentioned some concern about poor weight gain during a few of my previous visits. My body's way of saying: pay attention.
The alternative diagnosis is that I had an incidence of ketoacidosis, resulting in dehydration and imbalanced electrolyte concentrations and a very severe headache. I have never experienced diabetic ketoacidosis, so I can't be sure on this one - also, my blood sugar was only around 300, which hasn't ever pushed me into DKA before. However, I don't put it out of the realm of possibility because I am pregnant and my blood sugars had been so unstable and tending high for the 7-10 days prior. The other possibility is starvation ketoacidosis, but it may be generous to describe my state as one of starvation. After all, I was still eating; just not enough to gain weight necessary for healthy pregnancy. Needless to say, the causes of ketoacidosis seem complex, so this may or may not have been at issue.
The last possibility is that the same hormonal changes that I was undergoing that raised my blood sugars and made insulin needs higher (progesterone increase? estrogen drop?) also placed me at risk for a headache. I know that migraines are more common in women, and are associated with menstruation and childbearing events for this reason. I haven't had them before in my life, but did have one or two mild migraines during my first pregnancy.
So what I learned from this experience, and will continue to do through this third trimester and that of any other pregnancies I have:
Pay attention when your insulin needs increase dramatically, and respond accordingly. Moderate changes work well most of the time, and prevent lows, but the changes I needed really were dramatic and involved massive adjustments to bolus ratios, basal rates, and insulin sensitivity.
Be prepared to eat every 2 hours in the final weeks of pregnancy. As a corollary to the above, I would prefer the risk of making dramatic changes and having my blood sugars run low because for me, highs are much more difficult to deal with psychologically. I'm happy to be tied to my food every 2 hours. Keeps the weight gain up in any case, which keeps me, my OB, and my baby happy (even if my postpartum self disagrees. We'll deal with her later). My 16-month-old son is my snack-clock. I make sure I eat every time he does, which is at least 5 times a day.
Try Gatorade rather than juice or water. I should clearly get paid for this plug, but I have decided that Gatorade is an absolute necessity for me from here on out. I get more fluid per carb than I do with juice, which is important at this stage. It seems to be absorbed as fast, if not faster than, juice, when I'm dealing with a low. I don't have to go to the bathroom as frequently as I do if I drink just water. And it helps restore electrolyte concentrations, which is an important part of hydration and avoiding headaches. I'm hoping it will keep the charley-horse leg cramps that wake me up at night away for the rest of the pregnancy, too.