The luteal phase is the second half of your menstrual cycle, spanning from ovulation to the start of your next period. It typically lasts about 12 to 14 days. During this window, your body is essentially preparing for a possible pregnancy, and the hormonal shifts involved are responsible for many of the physical and emotional changes you notice in the days before your period.
Where It Falls in Your Cycle
Your menstrual cycle has two main halves. The first half, called the follicular phase, starts on the first day of your period and ends when you ovulate. The second half is the luteal phase, which begins immediately after ovulation and ends when your next period starts. While the follicular phase can vary quite a bit in length from person to person (and even cycle to cycle), the luteal phase is more consistent, usually staying close to 14 days.
What Happens Inside Your Body
The moment an egg is released from your ovary, the empty follicle it came from transforms into a temporary structure called the corpus luteum, a small yellowish mass of cells. This structure has one critical job: producing progesterone, along with some estrogen. Progesterone is the dominant hormone of the luteal phase, and it drives nearly everything that happens during these two weeks.
Rising progesterone thickens the lining of your uterus, creating a nutrient-rich environment where a fertilized egg could implant and grow. It also thickens your cervical mucus into a paste-like consistency, which acts as a barrier against bacteria entering the uterus. If you’ve been tracking cervical fluid, you’ll notice it becomes dry or almost dry after ovulation, a sharp contrast to the slippery, stretchy mucus that appears around your fertile window.
Your basal body temperature also shifts. After ovulation, it rises slightly, typically less than half a degree Fahrenheit (about 0.3°C). This small but measurable bump is caused by progesterone and stays elevated throughout the luteal phase, which is why temperature tracking can help confirm that ovulation has occurred.
What Happens if Pregnancy Occurs
If a fertilized egg implants in the uterine lining, it begins releasing a hormone called hCG (the same hormone detected by pregnancy tests). HCG signals the corpus luteum to keep producing progesterone rather than breaking down. The corpus luteum continues this job for roughly 12 weeks, at which point the placenta takes over progesterone production. After the handoff, the corpus luteum gradually shrinks and disappears.
What Happens if Pregnancy Doesn’t Occur
Without fertilization, the corpus luteum starts to break down about 10 days after ovulation. As it degrades, progesterone and estrogen levels drop sharply. That hormonal withdrawal destabilizes the thickened uterine lining, and within a few days, the lining sheds. That shedding is your period, and it marks the beginning of a new cycle.
Common Symptoms During the Luteal Phase
The hormonal shifts of the luteal phase are behind premenstrual symptoms, and they can be both physical and emotional. On the physical side, the most common complaints include bloating, breast tenderness, headaches, fatigue, muscle or joint aches, increased appetite, and sleeping more than usual. Swelling in the hands or feet can also occur.
Emotionally, many people experience irritability, anxiety, low mood, mood swings, or a feeling of being overwhelmed. Difficulty concentrating, forgetfulness, and social withdrawal are also common. These symptoms tend to appear in the second week of the luteal phase and resolve once your period begins.
For most people, these changes are mild to moderate and fall under the umbrella of PMS. A smaller percentage experience a more severe form called PMDD (premenstrual dysphoric disorder), where mood symptoms like sudden sadness, intense irritability, or feeling out of control are disruptive enough to interfere with daily life. Research suggests that it’s not necessarily higher hormone levels that cause these symptoms, but rather an increased sensitivity to the normal rise in progesterone and estrogen that occurs after ovulation.
When the Luteal Phase Is Too Short
A luteal phase lasting 10 days or fewer is considered short and is sometimes called luteal phase deficiency. The concern with a short luteal phase is that the uterine lining may not have enough time to develop properly, which can make it harder for a fertilized egg to implant. One study found this pattern in about 8% of cycles when defined as a luteal phase under 10 days combined with low midluteal progesterone.
Diagnosing luteal phase deficiency is tricky. The American Society for Reproductive Medicine notes there is no single, widely accepted test for it. Various thresholds have been proposed, including progesterone blood levels and luteal phase length, but none reliably distinguish fertile from infertile cycles. If you’re concerned about a consistently short luteal phase (especially while trying to conceive), tracking your cycle length and ovulation timing gives you useful data to bring to a healthcare provider.
How to Track Your Luteal Phase
Knowing when you ovulate is the key to identifying your luteal phase. The most accessible methods are basal body temperature charting and monitoring cervical mucus changes. When you see your temperature rise and your cervical fluid dry up, ovulation has likely occurred and your luteal phase has begun. Ovulation predictor kits, which detect a hormone surge in urine, can also help pinpoint the transition. Count the days from ovulation to the start of your next period, and that number is your luteal phase length. Tracking over several cycles gives you a reliable personal average.