Two weeks before your period, your body releases an egg in a process called ovulation. This single event sets off a cascade of hormonal shifts that affect everything from your body temperature and skin to your mood, appetite, and energy levels over the following 14 days. Understanding what’s happening during this stretch helps explain many of the physical and emotional changes you notice in the second half of your cycle.
Ovulation: The Main Event
The two-week countdown to your period begins with ovulation. Your brain releases a surge of luteinizing hormone (LH), which triggers one of your ovaries to release a mature egg. The LH surge starts about 36 hours before the egg is actually released, with the hormone hitting its peak roughly 10 to 12 hours before ovulation occurs.
You may actually feel this happen. Up to 40% of people who ovulate experience a sensation called ovulation pain: a mild twinge or sudden sharp ache on one side of the lower abdomen, on whichever side released the egg. For some people it lasts a few minutes, for others it lingers up to 48 hours. It’s not dangerous, but it can catch you off guard if you’ve never connected the sensation to your cycle.
Right around ovulation, your cervical mucus changes dramatically. It becomes clear, stretchy, and slippery, often compared to raw egg whites. This texture makes it easier for sperm to travel through the reproductive tract. If you’re tracking fertility, this mucus change is one of the most reliable signs that you’re in your most fertile window, typically spanning a few days around ovulation.
What Your Hormones Do After the Egg Is Released
Once the egg leaves the ovary, the empty follicle it came from transforms into a temporary structure called the corpus luteum. This small gland becomes a hormone factory, pumping out large amounts of progesterone and some estrogen. Progesterone production jumps dramatically: your body produces about 4 milligrams per day before ovulation, but that rises to around 25 milligrams per day during the middle of the luteal phase (roughly 8 to 9 days after ovulation). That’s more than a sixfold increase.
Estrogen follows a different pattern. It drops sharply right after ovulation, then rises again to a secondary peak around the middle of the luteal phase before falling once more as your period approaches. These two hormones work together to thicken and prepare the uterine lining for a potential pregnancy.
If sperm doesn’t fertilize the egg, the corpus luteum starts breaking down about 10 days after ovulation. As it degrades, progesterone and estrogen levels plummet. That withdrawal of hormones is what ultimately triggers your uterine lining to shed, starting your period.
Body Temperature and Metabolism
One of the subtlest changes happens to your core temperature. After ovulation, your basal body temperature rises slightly, typically less than half a degree Fahrenheit (about 0.3°C). It stays elevated throughout the luteal phase and drops back down when your period starts. This shift is driven by progesterone, which has a warming effect on the body. It’s small enough that you won’t feel feverish, but it’s consistent enough to be used as a fertility tracking method if measured first thing in the morning before getting out of bed.
Your resting metabolic rate also ticks upward during this phase. Your body burns slightly more calories at rest in the two weeks before your period compared to the first half of your cycle. Protein breakdown increases as well. This metabolic uptick may partly explain why many people feel hungrier or experience stronger cravings in the days leading up to menstruation. Your body is genuinely using more energy, so the urge to eat more isn’t imaginary.
Skin Changes
If you notice your skin getting oilier or breaking out in the second half of your cycle, hormones are the reason. Facial oil production fluctuates across the menstrual cycle, and the post-ovulation rise in progesterone stimulates your skin’s oil glands. This increased sebum production can clog pores and lead to the premenstrual breakouts that many people experience like clockwork. The effect tends to be most noticeable in the final week before your period, when hormonal shifts are at their most dramatic.
Mood, Sleep, and Brain Chemistry
Progesterone and estrogen don’t just act on your reproductive system. They directly influence brain chemistry, affecting neurotransmitters like serotonin (which regulates mood), GABA (which promotes calm and sleep), and dopamine (which drives motivation and pleasure). Progesterone and its byproducts have a calming, sedative-like effect on the brain by enhancing GABA activity and dampening excitatory signals. This is why some people feel more relaxed or sleepy in the days after ovulation.
Problems tend to arise when the balance between estrogen and progesterone shifts unevenly, particularly in the final days before your period when both hormones are crashing. That rapid withdrawal can leave serotonin and GABA activity disrupted, contributing to irritability, anxiety, low mood, and difficulty sleeping. For most people these shifts are mild and manageable. For those with more severe symptoms, the hormonal withdrawal may be triggering a heightened sensitivity in their brain’s neurotransmitter systems.
Sexual Desire Around Ovulation
Many people notice a spike in sexual desire right around ovulation, which makes evolutionary sense: this is the window when conception is possible. Research on ovulatory shifts in desire has found that this peak is most pronounced in people who are already in a relationship. For those without a current partner, the link between ovulation timing and desire was weaker. The increase in libido is thought to be one of several biological mechanisms that evolved to influence the timing of sexual activity around the fertile window.
After ovulation passes, desire often levels off or decreases as progesterone rises and the body shifts into a less fertile phase. Some people notice a second, smaller uptick in desire just before their period starts, possibly related to the hormonal changes happening as progesterone drops.
The Final Days Before Your Period
The last few days of the luteal phase are when most premenstrual symptoms concentrate. As the corpus luteum breaks down and hormone levels fall, you may notice breast tenderness, bloating, headaches, food cravings, and mood changes all intensifying. These symptoms are a direct result of your body responding to the withdrawal of progesterone and estrogen that had been sustaining the uterine lining.
The timeline varies from person to person. Some people feel symptoms starting a full week before their period, while others notice very little until a day or two before bleeding begins. The 14-day luteal phase is an average, not a fixed rule. It can range from about 10 to 16 days, which is why cycles vary in length even when ovulation is happening normally. If your luteal phase is consistently on the shorter end, you might feel like premenstrual symptoms arrive almost immediately after ovulation, leaving you with only a brief window of feeling “normal” in between.