Why is insulin considered the mainstay therapy for diabetes management in pregnancy?

Why is insulin considered the mainstay therapy for diabetes management in pregnancy?

• A. There is no placental transfer of insulin, and insulin resistance increases in the 2nd and 3rd trimesters
• B. Insulin crosses the placenta and protects the fetus
• C. Oral agents are always insufficient in pregnancy
• D. Insulin use is discouraged and rarely needed

Answer: (A)

In pregnancy, controlling the mother’s blood glucose is essential because glucose crosses the placenta and influences fetal growth. The reason insulin is the mainstay is twofold: first, insulin does not cross the placenta in meaningful amounts, so giving insulin to the mother lowers her blood glucose without delivering insulin to the fetus. Second, pregnancy hormones (like human placental lactogen, estrogen, progesterone, and cortisol) make the mother more insulin resistant, especially in the second and third trimesters, so the required insulin dose often increases as pregnancy progresses. This combination—safe maternal glucose control without fetal exposure to external insulin, plus the need to overcome rising insulin resistance—makes insulin the most reliable and effective therapy for managing diabetes in pregnancy.

In pregnancy, controlling the mother’s blood glucose is essential because glucose crosses the placenta and influences fetal growth. The reason insulin is the mainstay is twofold: first, insulin does not cross the placenta in meaningful amounts, so giving insulin to the mother lowers her blood glucose without delivering insulin to the fetus. Second, pregnancy hormones (like human placental lactogen, estrogen, progesterone, and cortisol) make the mother more insulin resistant, especially in the second and third trimesters, so the required insulin dose often increases as pregnancy progresses. This combination—safe maternal glucose control without fetal exposure to external insulin, plus the need to overcome rising insulin resistance—makes insulin the most reliable and effective therapy for managing diabetes in pregnancy.