What hormone is predominantly responsible for the observed laboratory changes, including hyperglycemia and increased serum C-peptide concentration, in a 36-year-old woman, gravida (number of times pregnant) 2, para (number of viable births) 1, at 30 weeks' gestation with polyhydramnios and a large for gestational age fetus?

From the Guidelines

The hormone predominantly responsible for the observed laboratory changes, including hyperglycemia and increased serum C-peptide concentration, in a 36-year-old woman at 30 weeks' gestation with polyhydramnios and a large for gestational age fetus is Human Placental Lactogen (HPL). This hormone, produced by the placenta during pregnancy, has insulin-antagonistic effects similar to growth hormone, leading to maternal insulin resistance 1. The increased insulin resistance causes the pancreas to produce more insulin, which is reflected in the elevated C-peptide levels observed in this patient. HPL's diabetogenic effect contributes to gestational diabetes, which explains the clinical findings of polyhydramnios (excess amniotic fluid) and a large for gestational age fetus. These are classic signs of poorly controlled maternal hyperglycemia, as excess maternal glucose crosses the placenta, stimulating fetal insulin production and subsequent fetal overgrowth. Key points to consider in the management of gestational diabetes include:

• Lifestyle behavior change is an essential component of management and may suffice as treatment for many individuals 1
• Insulin is the preferred medication for treating hyperglycemia in gestational diabetes mellitus, as other oral and non-insulin injectable glucose-lowering medications lack long-term safety data 1, 2
• The risk of gestational diabetes may be reduced by diet, exercise, and lifestyle counseling, particularly when interventions are started during the first or early in the second trimester 1, 2 The clinical presentation of this patient, including hyperglycemia, increased serum C-peptide concentration, polyhydramnios, and a large for gestational age fetus, is consistent with gestational diabetes, and HPL is the hormone predominantly responsible for these changes.

From the Research

Hormone Responsible for Laboratory Changes

The hormone predominantly responsible for the observed laboratory changes, including hyperglycemia and increased serum C-peptide concentration, in a 36-year-old woman at 30 weeks' gestation with polyhydramnios and a large for gestational age fetus is:

• Human placental lactogen (hPL) 3, 4 ### Role of Human Placental Lactogen Human placental lactogen (hPL) is a placental hormone that appears to have key metabolic functions in pregnancy, including:
• Inducing insulin resistance and increasing glucose levels in the mother 5, 4
• Regulating fetal growth and development 3, 6 ### Relationship Between hPL and Maternal Metabolic Conditions The relationship between hPL and maternal metabolic conditions, such as gestational diabetes, is complex and remains unclear 3
• Some studies have found that hPL levels are positively related to placental mass and infant birthweight in pregnancies affected by maternal diabetes 3
• Other studies have found that hPL levels are not significantly different in women with gestational diabetes compared to those with normal glucose tolerance 4 ### Other Hormones Involved Other hormones, such as prolactin and human placental growth hormone (hPGH), may also play a role in regulating maternal metabolism and fetal growth during pregnancy 5, 6
• Prolactin has been shown to regulate adipocyte biology, glucose and lipid metabolism, and may guard postpartum women against type 2 diabetes 5
• hPGH has been shown to replace pituitary GH during pregnancy and is correlated to serum IGF-I in normal pregnancies 6