The luteal phase is the second half of your menstrual cycle, spanning from ovulation to the first day of your next period. It typically lasts about 14 days and is driven primarily by progesterone, the hormone responsible for preparing your uterine lining to receive a fertilized egg. If pregnancy doesn’t occur, progesterone drops, the lining sheds, and your period begins.
When It Starts and Ends
The luteal phase begins the moment an egg is released from the ovary. After ovulation, the empty follicle left behind transforms into a temporary hormone-producing structure called the corpus luteum (named for the yellow pigment it accumulates). This structure pumps out progesterone and smaller amounts of estrogen for roughly two weeks.
If the egg isn’t fertilized, the corpus luteum starts to break down about 9 to 11 days after ovulation. As it degrades, progesterone levels fall sharply. That drop triggers the blood vessels supplying the uterine lining to constrict, cutting off blood flow to the surface layers. The tissue breaks down, the uterus contracts, and menstruation begins. The old corpus luteum eventually becomes a small bit of scar tissue on the ovary. If pregnancy does occur, the embryo sends a hormonal signal that keeps the corpus luteum alive and producing progesterone until the placenta takes over.
What Progesterone Does During This Phase
Progesterone is the defining hormone of the luteal phase. While estrogen dominated the first half of your cycle, building up the uterine lining, progesterone now takes over to mature and stabilize it. The lining’s glands begin secreting nutrients and fluids that would nourish an embryo in its earliest days. These changes are so precise and predictable that a tissue sample of the lining can be “dated” to a specific day of the luteal phase based on its microscopic appearance alone.
Progesterone also raises your core body temperature by 0.3°C to 0.7°C (roughly half a degree to just over one degree Fahrenheit). This temperature shift appears about 24 hours after progesterone starts rising, plateaus within 48 hours, and stays elevated until progesterone falls near the end of the phase. That sustained warmth is what makes basal body temperature tracking a reliable way to confirm that ovulation has occurred, though it can’t predict ovulation in advance.
The Implantation Window
Not every day of the luteal phase is equally hospitable to an embryo. The uterine lining reaches a state of receptivity only during a narrow window, roughly days 20 to 24 of a standard 28-day cycle. That translates to about 7 to 11 days after the hormonal surge that triggers ovulation. During this window, the lining has the right structure, blood supply, and molecular signaling to allow a blastocyst (the early embryo) to attach and begin implanting.
Outside this window, the lining either hasn’t matured enough or has already begun to destabilize. This is one reason why the luteal phase’s length and hormonal output matter so much for fertility. A phase that’s too short or produces too little progesterone may not give the lining enough time to become fully receptive.
Common Symptoms You May Notice
The hormonal shifts of the luteal phase produce a recognizable set of physical and emotional changes. In the first several days after ovulation, when progesterone is climbing, many people feel relatively calm, even slightly sluggish. Breast tenderness, bloating, and mild fluid retention are common as progesterone peaks around mid-luteal phase.
As the corpus luteum starts declining and both progesterone and estrogen drop in the final days before your period, premenstrual symptoms tend to intensify. Mood changes, irritability, food cravings, headaches, and fatigue all cluster in this late-luteal window. These are the symptoms commonly grouped under PMS. The severity varies enormously from person to person and even cycle to cycle, but the timing is consistent: the last few days of the luteal phase, when hormones are falling fastest.
How Long Is Normal
The luteal phase is relatively constant compared to the first half of the cycle. While the follicular phase (before ovulation) can vary widely, causing cycles to be shorter or longer overall, the luteal phase holds steady at around 14 days for most people. A range of 12 to 14 days is considered typical.
A luteal phase shorter than 10 days is sometimes called a luteal phase deficiency. The concern is that there isn’t enough time, or enough cumulative progesterone exposure, for the uterine lining to fully mature and sustain an early pregnancy. Research from the American Society for Reproductive Medicine suggests that normal lining development may require peak progesterone levels between 8 and 18 ng/mL, though progesterone is released in pulses throughout the day, making any single blood draw an imperfect snapshot.
Conditions that can shorten the luteal phase or reduce progesterone output include thyroid disorders, high prolactin levels, excessive exercise, significant calorie restriction, and the natural transition toward menopause. Polycystic ovary syndrome can also affect luteal phase quality, though its primary impact is on ovulation itself.
Tracking Your Luteal Phase
If you’re trying to understand your cycle or optimize fertility, knowing your luteal phase length gives you useful information. The simplest method is to identify your ovulation day (using ovulation predictor kits, basal body temperature charting, or cervical mucus monitoring) and count the days until your period starts. The day after ovulation through the last day before bleeding is your luteal phase.
Basal body temperature is particularly useful here because it gives you a visible marker of the phase transition. When your resting temperature shifts upward and stays elevated for at least three consecutive days, you’ve likely entered the luteal phase. If that elevated temperature lasts 11 days or fewer before dropping and your period arriving, it’s worth mentioning to a healthcare provider, especially if you’re trying to conceive.
For people not tracking fertility, simply understanding the luteal phase can help make sense of cyclical symptoms. The breast soreness, bloating, and mood changes that seem to appear out of nowhere have a predictable hormonal cause, and they follow a predictable timeline tied to the corpus luteum’s lifespan.