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Diabetes in pregnancy

Visit us (http://www.khanacademy.org/science/healthcare-and-medicine) for health and medicine content or (http://www.khanacademy.org/test-prep/mcat) for MCAT related content. These videos do not provide medical advice and are for informational purposes only. The videos are not intended to be a substitute for professional medical advice, diagnosis or treatment. Always seek the advice of a qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read or seen in any Khan Academy video. Created by Nauroz Syed.

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Video transcript

- [Voiceover] Diabetes, it's certainly not a problem that's unique to pregnancy, but it's something we always have to discuss when we're talking about pregnancy because it can really complicate that picture quite a bit. So firstly, diabetes and pregnancy split up into two different categories. There's the category of women who had diabetes before becoming pregnant, and that's called pre-gestational diabetes. So that category is referred to as pre-gestational diabetes. Pre for before, gestational for pregnancy, so before pregnancy diabetes. And then there are the women who become diabetic during their pregnancy, which is called gestational diabetes. So that's the second category, gestational diabetes. And 90% of cases, so that's nine of every 10 cases of diabetes in pregnancy falls into this category of gestational diabetes. And then the other 10% are pre-gestational diabetics. So there's something about pregnancy that makes women more susceptible to developing diabetes and we'll discuss exactly what that is in just a bit. But firstly, why do we even split up diabetes into these two different groups? Well, if a woman has pre-gestational diabetes, that means that her blood sugars may have been poorly controlled at the time that the baby was conceived. Or even during the first eight weeks of the pregnancy, during a period called organogenesis. So the first eight weeks of pregnancy is a period called organogenesis, when the fetus' organs are made. And those high levels of glucose during that really pivotal time can lead to a miscarriage or it can lead to significant anomalies within the fetus. However, with gestational diabetes, that problem with glucose control develops during the pregnancy, in some ways because of the pregnancy. And usually the glucose control isn't impaired until the second trimester, so after the point of conception and after the point of organogenesis. So miscarriage and fetal anomalies don't tend to be a problem with gestational diabetes. But that's not to say that gestational diabetes doesn't harm the fetus. Rather, diabetes as a whole, so regardless of the category, can cause preterm labor. It can cause problems with the growth of the fetus. It can even lead to stillbirth. And one of the complications that we tend to think about a lot, that tends to be talked about a lot, is fetal macrosomia. So fetal macrosomia. So let me explain that a little bit. Alright, so if mom has diabetes, the basic gist of it all is that her glucose levels tend to run on the high side. And glucose can cross the placenta, into the bloodstream of the fetus. That's like one of the main purposes of the placenta, to allow glucose to enter the baby's bloodstream as an energy supply. So then when mom has high glucose levels in her blood, then the fetus has high glucose levels in its blood. And that drives the release of insulin in the fetus, because that's the body's primary response to glucose, to release insulin. Insulin is kind of the key that allows cells to open up their doors and take up glucose and use it. And so that insulin that's released in the fetus allows glucose to be taken up. And insulin does a few other things. It also stimulates fat storage in the body, right? And it also binds to receptors on different organs, such as the heart and the liver, and it causes them to grow. It causes the organs to actually grow in size. And so the end result of it all, the end result of the high glucose levels in the mom, leading to high glucose levels in the baby, leading to high insulin levels in the baby, is that the baby grows to a larger size than normal, which is called fetal macrosomia. Macro for large and soma for body. So larger body. Now another thing that I want to mention is that in pre-gestational diabetes, so again, diabetes before the point of pregnancy, the impaired glucose control is more long-standing. So these women are more likely to have diabetic complications such as kidney damage or vascular problems, so blood vessel related problems, and damage to the retina. And pregnancy can aggravate these complications, so it can it make worse. So it's really important to monitor these conditions throughout the pregnancy. Now, I want to stop dancing around the issue of why women can become diabetic during pregnancy. A lot of it has to do with the hormones that are released during pregnancy. So hormones such as HPL, that's not one that many people have heard of, right? It stand for human placental, human placental lactogen. Alright, so that's HPL. Another hormone is cortisol. So the body's main stress hormone. Another one that you may have heard of before is growth hormone, that's released in a large quantity during pregnancy. And then finally, progesterone. Progesterone, which is exceptionally important for the maintenance of a healthy pregnancy. So these hormones are released during pregnancy and they have lots of important roles. And among their many, many roles, these hormones increase mom's production of glucose during pregnancy to make sure that the fetus has enough of the glucose, enough of its primary fuel source. And that leads to high glucose levels within the mom's blood. And you might be thinking, "Well, that's no problem, "because the glucose will cause insulin to be released "and that insulin will cause mom's cells "to take up the glucose and problem solved. "You don't have high glucose levels in the blood any more." Well, unfortunately, it doesn't really work that way, because these same hormones make the mom's body resistant to insulin. So that the cells don't respond to insulin and don't take up as much glucose from the blood. And this is done for a purpose. It's actually done so that you can reduce mom's utilization of the glucose so that more of the glucose is available for the fetus. And that's why you can end up with high blood glucose levels and diabetes in pregnancy. Or if you had diabetes before you became pregnant, it can become worse during pregnancy. So, given that diabetes can cause all of these complications for mom and baby during pregnancy, it goes without saying that we do our absolute best to screen for it during pregnancy. So for women who have a normal risk of having diabetes, we do a routine screen. So for all women, all average women, we do a routine screen around 26 to 28 weeks into the pregnancy. And that screening test is usually in the form of a glucose tolerance test. So the screening test is often called the glucose tolerance test, where the woman is given a very specific amount of glucose and her blood glucose levels are measured at one, two, or three hours after consuming that very specific amount of glucose. And if her blood glucose levels are above the normal range, then she's found to be diabetic. And if a woman is diagnosed with diabetes during her pregnancy, we do our best to control it with diet. And if that doesn't work, then insulin is kind of our second line of treatment. And it's also important to know that gestational diabetes, so again, diabetes that occurs during pregnancy, kind of as a process of pregnancy, increases the risk of a woman having overt diabetes after the pregnancy is over. So it's really important to follow up with all these women after they deliver. Kind of the set point, six weeks after they deliver to test them for diabetes. Okay, so that is gestational diabetes in a nut shell.