Corpus Luteum Deficiency (CLD)

Corpus Luteum Deficiency (CLD) is a condition in which the corpus luteum does not produce enough progesterone. The corpus luteum is the small gland that forms where an egg was released. Its progesterone prepares the uterine lining for implantation, the attachment of an embryo. It also supports early pregnancy. CLD names the point where the problem starts: the corpus luteum itself. A related term, Luteal Phase Deficiency (LPD), is broader. LPD describes a weak or short phase after ovulation. It can have more than one cause. The gland may produce too little progesterone, or produce it for too short a time. The uterine lining may also respond poorly to normal progesterone (progesterone resistance).¹ CLD is one cause of LPD, not the only one. A low progesterone result shows that a problem exists. It does not show where the problem started. Treating the result without finding the source can leave the actual cause in place.

Standard infertility evaluations often miss CLD. In one cohort of infertile couples, 0% had a diagnosis of corpus luteum deficiency before their RRM evaluation. After detailed, cycle-timed testing, 71% received the diagnosis.² Standard evaluations often rely on one progesterone blood test in the middle of the second half of the cycle. One value cannot show how well the corpus luteum functions. The gland releases progesterone in pulses across that phase. A single test can appear normal while the total output across the phase is too low.

NaProTechnology evaluates CLD with several progesterone tests timed to the charted cycle after Peak Day, rather than one blood draw. A flat, falling, or steadily low progesterone curve points to the corpus luteum itself.³ NaProTechnology care examines the phase after ovulation and, when needed, the phase before it. A healthy corpus luteum depends on a healthy follicle. A follicle that stays small, grows slowly, or releases its egg too early leaves a weaker corpus luteum. Supporting healthy follicle growth before ovulation corrects the problem at its source. Support after ovulation is timed to the cycle chart through Peak-plus series testing rather than a calendar estimate.

CLD is a common finding in couples with unexplained infertility. It is also common in couples who have had an early pregnancy loss. The hormone signal from the early embryo also matters. That signal is hCG, and it keeps the corpus luteum working in early pregnancy. If the embryo produces too little hCG, the corpus luteum can fail even when the gland itself is healthy. After an early loss, a cause-based evaluation examines both sides: the corpus luteum and the embryo's signal to it.