Prolactin concentrations in normal menstrual cycles and conception cycles.

Area of Science:

• Reproductive Endocrinology
• Hormonal Assays
• Human Physiology

Background:

• Prolactin is a hormone crucial for reproduction.
• Understanding prolactin levels is important for fertility assessments.
• Previous studies have explored prolactin's role in ovulation and conception.

Purpose of the Study:

• To analyze plasma prolactin concentrations during the menstrual cycle.
• To determine if prolactin levels differ between conception and non-conception cycles.
• To establish reference ranges for prolactin in ovulating women and for conception.

Main Methods:

• Daily measurement of plasma prolactin concentrations over 23 menstrual cycles.
• Statistical analysis of prolactin data, including frequency distribution and logarithmic transformation.
• Determination of mean concentrations and 95% confidence limits using probability plots.

Main Results:

• Prolactin concentrations followed a log-normal distribution in all cycles.
• Mean prolactin levels were 302 (106-871) mU/l in non-conception cycles and 178 (58-550) mU/l in conception cycles.
• A distinct prolactin population was observed between conception and non-conception cycles.

Conclusions:

• The normal range for prolactin in ovulating women is suggested as 80-800 mU/l.
• Optimal prolactin levels for conception appear to be lower, approximately 60-600 mU/l.
• Hyperprolactinemia is defined as prolactin concentrations exceeding 800 mU/l.