Premature Luteinization (PL)

Definition - What does Premature Luteinization (PL) mean?

Premature luteinization (PL) is defined as a rise in luteinizing hormone (LH) called LH surge, and eventually, a rise in progesterone levels, before receiving the hCG trigger shot as part of controlled ovarian stimulation. PL compromises the growth of the ovarian follicle and egg, fertilization, embryo quality, and eventually the chances of a successful pregnancy.

FertilitySmarts explains Premature Luteinization (PL)

Normally, a hormonal medication like hCG is administered to trigger the "LH surge" and ovulation, leading to an empty yellow follicle, now known as the corpus luteum, which produces progesterone to support and maintain the pregnancy. With PL, the LH surge occurs prior to the hCG shot.

What triggers premature luteinization is not entirely clear. It may occur as a chain of ovarian events, such as increased LH sensitivity of the receptors located on the ovarian cells due to higher cumulative exposure to estrogen from a previous cycle. PL predominantly affects women with advanced age and those with diminished ovarian reserve.

PL favors premature ovulation. The resultant corpus luteum cannot produce adequate progesterone to support the pregnancy. This compromises egg quality with the affected eggs carrying an abnormal number of chromosomes after cell division, resulting in a failed IVF cycle. The condition can be prevented by customizing the IVF stimulation protocols for controlled ovarian stimulation as well as modifying the dose, schedule, and type of the hCG trigger shot.

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