07/28/2023
🩸28 week labs🩸
Let’s talk about lab work at 28 weeks gestation. Usually at this visit we are drawing blood for two things - the gestational diabetes screen and a CBC (complete blood count). So what’s so important about these lab values?
Gestational diabetes (GDM) screen: during pregnancy, the placenta makes a lot of extra hormones that the body isn’t used to. One of which (human placental lactogen) causes cellular resistance to insulin, making it more difficult for the body to move glucose out of the blood and into the tissues where it can be used. For most people, their body compensates by increasing insulin production, but in about 6-7% of people, the body does not compensate, and gestational diabetes (GDM) occurs. It’s also important to note that about 50% of people diagnosed with GDM have NO symptoms, which is why it’s so important to screen, and why providers need to check their biases 🤔
Why do we care? Uncontrolled GDM can put folks at higher risk of poor outcomes for parent and baby. Specifically birth trauma, newborn hypoglycemia (low blood sugar), and newborn respiratory distress.
Fortunately, blood glucose levels respond almost immediately to dietary changes, exercise, as well as stress reduction. The midwifery model of care allows midwives to spend the extra time discussing nutrition and stressors to help come up with a care plan to manage glucose levels.
CBC (complete blood count): during pregnancy, blood volume expands by 30-50% (holy moly amiright?). However, red blood cells take a little extra time catching up (this is called hemodilution) which means the blood is made up of mostly plasma. Red blood cells are responsible for carrying the oxygen in our blood. We expect a body’s oxygen carrying capacity to be the lowest at 28 weeks, and then the red blood cells to start catching up from there. A CBC can tell us what the body’s oxygen carrying capacity is and if we need to supplement to boost it. It also gives us information on the body’s platelet count and white blood cells.
For more information about GDM, check out