Updated by the Progyny Clinical Team — August 2025.
If you’re trying to conceive, you probably know hormones play a big role in the process. What you may not know is how hormone levels shift during each phase of the menstrual cycle. Subtle changes can make a difference, and in some cases, they may play a role in difficulty getting pregnant. One condition related to this is called luteal phase deficiency, or LPD.
Understanding the luteal phase
The luteal phase is the part of your menstrual cycle that starts after ovulation — when a mature egg is released — and ends when your next period begins. It usually lasts about 14 days, but it can range from 10 to 16 days.
After ovulation, the cells left behind in the ovary form what’s called the corpus luteum. This structure makes the hormone progesterone, which is essential for early pregnancy. Progesterone thickens the lining of the uterus (endometrium) so it’s ready for an embryo to attach and grow.
What is luteal phase deficiency?
LPD, sometimes called luteal phase defect, happens when the body doesn’t make enough progesterone during the luteal phase. A “short luteal phase” means it lasts fewer than 10 days.
Possible causes of LPD
Several factors may contribute to LPD, including:
- Hormone imbalances involving gonadotropin-releasing hormone, follicle-stimulating hormone, or luteinizing hormone, which can affect estrogen and progesterone production. This includes conditions like polycystic ovary syndrome, endometriosis, obesity, anorexia, or pituitary disorders.
- Thyroid conditions or abnormal prolactin levels.
- Having recently given birth.
- Certain medical conditions, such as a history of a kidney transplant.
How it might affect fertility
Low progesterone levels have plausibly been linked to infertility and early pregnancy loss, however LPD has not been found to be an independent cause of infertility and recurrent pregnancy loss.
One concern with a short luteal phase is that if progesterone drops too soon, the uterine lining may break down. This can trigger menstrual bleeding or possibly cause an early miscarriage. Without enough progesterone — and without a thick, healthy uterine lining — an embryo may not be able to implant and grow successfully.
Treatment options
Currently, no treatment has been proven to improve pregnancy rates in unmedicated cycles. In medicated or stimulated cycles, some healthcare providers recommend luteal support with progesterone, which may help improve the chances of maintaining a pregnancy.
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Disclaimer: The information provided by Progyny is for educational purposes only and is not medical advice. Always consult a qualified healthcare provider for medical guidance.