Lecture 13 Endocrine and metabolic disorders of pregnancy Flashcards
Gestational diabetes mellitus (GDM)
Carbohydrate intolerance with the onset or first recognition occurring during pregnancy; it does not exclude the possibility that the glucose intolerance preceded the pregnancy.
Fetal glucose and insulin
- Glucose crosses the placenta; insulin does not.
2. The fetus begins to produce its own insulin around 10 weeks.
Hypoglycemia during the 1st trimester
Occurs as a result of rising levels of estrogen and progesterone - stimulates an increase in insulin production. Fasting levels of blood glucose fall by 10% - important for women with insulin-dependent (type 1) diabetes.
Diabetogenic state during the 2nd and 3rd trimesters
- Hormonal changes result in a decreased tolerance to glucose, increased insulin resistance, decreased hepatic glycogen stores, and increased hepatic production of glucose.
- Maternal insulin requirements gradually increase from approx. 18 to 24 weeks to approx. 36 weeks.
Preconception counseling is critical in the safe management of diabetic pregnancies. Which complication is commonly associated with poor glycemic control before and during early pregnancy?
Congenital anomalies in the fetus. [Frequent episodes of maternal hypoglycemia may occur during the first trimester (not before conception) as a result of hormonal changes and the effects on insulin production and use. Hydramnios occurs approximately 10 times more often in diabetic pregnancies than in nondiabetic pregnancies. Typically, it is observed in the third trimester of pregnancy. Hyperemesis gravidarum may exacerbate hypoglycemic events because the decreased food intake by the mother and glucose transfer to the fetus contribute to hypoglycemia.]
Screening at 24 weeks of gestation reveals that a pregnant woman has gestational diabetes mellitus (GDM). In planning her care, the nurse and the client mutually agree that an expected outcome is to prevent injury to the fetus as a result of GDM. This fetus is at the greatest risk for which condition?
Macrosomia. [Poor glycemic control later in pregnancy increases the rate of fetal macrosomia. Poor glycemic control during the preconception time frame and into the early weeks of the pregnancy is associated with congenital anomalies. Preterm labor or birth is more likely to occur with severe diabetes and is the greatest risk in women with pregestational diabetes.]
A client with maternal phenylketonuria (PKU) has come to the obstetrical clinic to begin prenatal care. Why would this preexisting condition result in the need for closer monitoring during pregnancy?
The fetus may develop neurologic problems. [Children born to women with untreated PKU are more likely to be born with mental retardation, microcephaly, congenital heart disease, and low birth weight.]
A new mother with a thyroid disorder has come for a lactation follow-up appointment. Which thyroid disorder is a contraindication for breastfeeding?
PKU. [PKU is a cause of mental retardation in infants; mothers with PKU pass on phenylalanine and therefore should elect not to breastfeed.]
Which major neonatal complication is carefully monitored after the birth of the infant of a diabetic mother?
Hypoglycemia. [The neonate is at highest risk for hypoglycemia because fetal insulin production is accelerated during pregnancy to metabolize excessive glucose from the mother. At birth, the maternal glucose supply stops and the neonatal insulin exceeds the available glucose, thus leading to hypoglycemia.]
Which physiologic alteration of pregnancy most significantly affects glucose metabolism?
Placental hormones are antagonistic to insulin, thus resulting in insulin resistance. [Placental hormones, estrogen, progesterone, and human placental lactogen (HPL) create insulin resistance. Insulin is also broken down more quickly by the enzyme placental insulinase.]
To manage her diabetes appropriately and to ensure a good fetal outcome, how would the pregnant woman with diabetes alter her diet?
Eat her meals and snacks on a fixed schedule. [Having a fixed meal schedule will provide the woman and the fetus with a steady blood sugar level, provide a good balance with insulin administration, and help prevent complications.]
Target fasting blood glucose level (diabetic pt. during pregnancy)
60 to 99 mg/dL.
Target blood glucose level 1 hour after a meal (diabetic pt. during pregnancy)
110 to 129 mg/dL.
Target blood glucose level 2 hours after a meal (diabetic pt. during pregnancy)
120 mg/dL or less.
3-hour oral glucose tolerance tolerance (100 g) screening - positive values
Fasting 95 mg/dL 1 hour 180 mg/dL 2 hours 155 mg/dL 3 hours 140 mg/dL *If two or more of these are met or exceeded, the woman has GDM.*
