E1G and PDG Elevation in Early Pregnancy During Luteal Phase
Yes, both estrone-3-glucuronide (E1G) and pregnanediol-3-glucuronide (PDG) levels will be elevated and remain elevated during the luteal phase if pregnancy occurs, distinguishing conception cycles from non-conception cycles. 1
Hormonal Patterns in Pregnant vs Non-Pregnant Luteal Phases
E1G (Estrone-3-Glucuronide) Elevation
E1G concentrations are significantly higher throughout conception cycles compared to non-conception cycles, with an average difference of 18-20 ng/mg creatinine daily. 1
In clinical pregnancy cycles, E1G levels remain elevated during the late luteal phase, whereas they drop in non-conception cycles. 2
The late luteal rise in estradiol (measured as E1G in urine) is a more sensitive indicator of pregnancy than progesterone elevation alone. 2
Women who achieve clinical pregnancy demonstrate consistently higher E1G levels throughout their cycles compared to their own non-conception cycles. 1
PDG (Pregnanediol-3-Glucuronide) Elevation
PDG rises approximately 24-36 hours after ovulation and remains elevated throughout the luteal phase in pregnancy cycles. 3
Three consecutive positive PDG tests (≥5 μg/mL threshold) after the LH surge confirm ovulation with high specificity, and these levels remain elevated in conception cycles. 3
In fertile cycles that result in pregnancy, late luteal progesterone levels remain higher than midluteal values, whereas they drop in non-fertile cycles. 2
Clinical Significance for Pregnancy Detection
Distinguishing Features
Both E1G and PDG measurements in urine are markedly elevated during pregnancy, making them useful for early pregnancy detection. 4
E1G measurement is particularly valuable for early pregnancy diagnosis, while sustained elevation of both hormones confirms ongoing pregnancy. 4
The progesterone/estradiol ratio remains stable during the luteal phase in both fertile and non-fertile cycles, but the absolute levels differ significantly. 2
Timing Considerations
During normal luteal phases in non-pregnant women, E1G rises again during the mid-luteal phase (7-10 days post-ovulation), reaching levels 2-3 times higher than early follicular baseline. 5
In pregnancy, this elevation persists and increases further rather than declining in the late luteal phase. 2
Practical Application
Low E1G levels (<30 ng/mg Cr, below the 10th percentile) during the early luteal phase are associated with increased odds of early pregnancy loss (OR = 4.8). 1
The sustained elevation of both E1G and PDG beyond the expected late luteal decline is the key distinguishing feature of early pregnancy. 1, 2