While you may want your menstrual cycle to be regular, ovulation isn't always on time. Your periods are "irregular" if they come less than 21 days or more than 35 days apart. Your menstrual cycle length might even change month to month. That's because you may have late ovulation.
Although some periods are so regular that you can predict the day and time it will start, many can still have late ovulation. The time from the first day of your last period to the start of your next period is usually about 28 days. Ovulation happens during the middle of your menstrual cycle, around day 14, and your ovary releases an egg.
During ovulation, the egg can be fertilized, and you can become pregnant. But with late ovulation, the egg isn't released until later in your cycle. And if you're trying to get pregnant, you may need to adjust your schedule because your egg isn't fertile until later in your cycle.
Learn more about what ovulation is, how to know if you're ovulating, and treatments for late ovulation.
Ovulation: What Is It?
Ovulation is the release of an egg from your ovary. The egg can be fertilized by sperm to make a baby. There are about six days in the middle of your menstrual cycle when you can get pregnant.
This is called your fertile window. You're more likely to get pregnant if you have sex without birth control:
- In the three days before ovulation
- Up to the day of ovulation
A man's sperm can live for three to five days in a woman's reproductive organs. But a woman's egg only lives for about 12-24 hours after ovulation. The time between ovulation and the beginning of your next period is usually 7-16 days.
How Do You Know When You're Ovulating?
There are many ways to tell when you're ovulating. You can take your basal body temperature or use an ovulation predictor kit.
Basal body temperature for ovulation
Your doctor may ask you to take your temperature before you get out of bed each day — it's called your basal body temperature. This temperature can help you know if or when ovulation is occurring.
You'll need a special thermometer called a basal body temperature thermometer. It's made for taking your basal body temperature, or you can use a mercury thermometer. Your doctor may ask you to chart or log your temperature every day for your entire menstrual cycle.
Your temperature stays low until right before ovulation, usually 96 F to 98 F. After you ovulate, your temperature rises to 97 F to 99 F. A raise of more than 0.5 F (0.28 C) in temperature for many days usually means you've ovulated, but it can rise from 0.4 F (0.22 C) to 1 F (0.56 C).
Your doctor may also ask you to look for vaginal mucus changes. Right before you ovulate, your mucus gets clear, stretchy, and slippery. Remember, your basal body temperature can't predict when ovulation will occur. It can only suggest it has happened.
Ovulation predictor kits
A more precise way to tell if you're ovulating is to use an ovulation predictor kit. These kits often spot the surge of luteinizing hormone (LH). Your LH gets higher about 12-36 hours before you ovulate. But with late ovulation, your LH may not surge until later in your cycle. Unlike your basal body temperature, these kits can predict when you'll ovulate.
Here are some ovulation kits you can get:
- LH urine tests, about 97% accurate
- LH and estrogen test (Clearblue easy fertility and Clearblue digital monitor), 95%-97% accurate
- Underarm temperature (DuoFertility), 100% accurate
- Vaginal temperature (OvuSense), 99% accurate for ovulation but 89% for predicting it
- Microscope to look for saliva changes, only 42%-53% accurate
What Is Considered Late Ovulation?
Your menstrual cycle can be shorter or longer, but it typically lasts 21-35 days. Late ovulation happens when the egg is released later in your cycle.
Usually, your cycle goes through three phases:
- Follicular (before the release of the egg)
- Ovulatory (the release of the egg), sometimes called your "mid-cycle surge"
- Luteal (after the release of the egg)
This last phase, the luteal phase, lasts about 12-14 days. So if your period comes every 28 days, you likely ovulate around day 14. But if your period comes every 35 days, you won't ovulate till around day 21.
"If a woman ovulates beyond cycle day 21, her total cycle length will likely be beyond 35 days and outside the range of normal cycle frequency," says Rhiana Saunders, MD, reproductive endocrinologist and infertility specialist at Aspire Houston Fertility Institute in Texas. "Late or possibly absent ovulation should be suspected with regular menstrual cycles beyond 35 days."
As you get older, your cycle can shorten, but longer menstrual cycles can mean anovulation. That means you don't release an egg from your ovary, you lack ovulation, or it's absent. When ovulation is irregular — but not completely absent — it is known as oligo-ovulation.
Both anovulation and oligo-ovulation are types of ovulation problems. These ovulatory problems can lower your chance for pregnancy. Ovulation may or may not happen if you are:
- Pregnant. You will not ovulate.
- Breastfeeding. You may or may not ovulate.
- In transition to menopause (perimenopause). You may not ovulate every month.
- Past menopause. You do not ovulate.
What Causes Late Ovulation?
When luteinizing hormone peaks later in your cycle than you expect, late ovulation happens.
How do hormones influence ovulation timing?
LH is a hormone released by your brain to tell your ovary to release an egg. LH levels begin to get higher about 36 hours before you ovulate. You'll get a surge of LH that peaks about 12 hours before ovulation.
An area in your brain called the hypothalamus controls reproduction along with the pituitary gland, ovaries, and more.
When you have problems with late ovulation, your:
- Hypothalamus may not make enough gonadotropin-releasing hormone (GnRH)
- Pituitary gland may produce too little LH or follicle-stimulating hormone
- Ovaries may not make enough estrogen
- Pituitary gland may make too much prolactin (needed to make milk), and turn off hormones needed to ovulate
- Other glands may not work right, like your adrenal glands can make too many androgens or your thyroid can make too much or too little thyroid hormone
Is late ovulation linked to any medical conditions?
Polycystic ovary syndrome (PCOS) is the most common cause of late ovulation. Your ovaries may not work the way they should because of extra androgens (higher levels of the hormone androgen).
But many other medical conditions are linked to late ovulation, such as:
- Hypothyroidism
- Breastfeeding
- High prolactin levels (hyperprolactinemia)
- Certain medications (such as estrogens, progestins, and more)
- Endometriosis
- Uterine fibroids
- Chronic stress can delay your cycle
- Weight loss, if it's rapid because your body sees it as stress
- Diabetes, especially type 1 diabetes
- Obesity
- Excessive exercise
- Ovarian failure at an earlier age (primary ovarian insufficiency)
- Getting older (as you get near menopause)
Signs and Symptoms of Late Ovulation
With late ovulation, you'll likely have signs and symptoms of regular ovulation. You may just get signs later in your cycle, such as:
- Clear, stretchy cervical mucus
- Mild pelvic or abdominal pain
- Higher sex drive (libido)
- Breast tenderness
- A higher basal (resting) body temperature
Do ovulation tracking apps work for irregular cycles?
Not well, because the tracking apps attempt to predict your next period, and you'll need to be regular. If you're irregular, the app may not predict ovulation at the right time.
Some apps use a wider ovulation (fertility) window, and this can help. But it can also mean a longer time without sex if you're trying to avoid pregnancy. With an irregular cycle, the app may miss your fertile time, too. It just depends on how late you ovulate in your cycle.
The app can be a great place to look for patterns about your irregular cycle. Knowing your unique symptoms can help you know when you'll ovulate.
How Is Late Ovulation Diagnosed by Health Care Providers?
Your doctor will review your medical history and do an exam. They'll look for the cause of your irregular cycle and the reason for late ovulation.
At first, your doctor may suggest that you:
- Chart your menstrual cycles for a few months
- Take and log your basal body temperature
- Get a blood test that checks your hormone levels (progesterone, LH, and more)
Charting your basal body temperature can help your doctor know if you've ovulated, but it isn't very precise.
Your doctor can also order a transvaginal ultrasound to see images of your ovary. This imaging scan inserts a probe into your vagina and uses sound waves to spot any problems with your reproductive organs or ovaries.
Your doctor may also measure the level of progesterone in your blood. A blood test can tell if you have higher progesterone levels after ovulation.
Can you ovulate late and still get pregnant?
"Yes, you can," says Kay Waud, MD, reproductive endocrinologist at HRC Fertility in San Francisco. "Even if it's late, there's still a chance of conception."
"Ovulation refers to the release of an egg from the ovary, which then travels into the fallopian tube where it can be fertilized by sperm," Waud says. "Pregnancy success rates don't differ a lot among women with different ovulation patterns as long as you ovulate."
But if your hormones are not balanced, you can ovulate late. Luckily, you can get "hormonal support during the second half of your cycle," Waud says. This can help raise your chances of getting pregnant.
How Do You Treat Late Ovulation?
Your doctor may talk to you about reaching your goal weight and suggest some habit changes to help bring on ovulation. Some lifestyle changes can mean quitting smoking, avoiding alcohol, and lowering your caffeine intake.
Depending on the cause, your doctor may prescribe medicines such as:
- Clomiphene
- Letrozole
- Metformin
- Hormone therapy (human gonadotropins containing follicle-stimulating hormone and, sometimes, luteinizing hormone)
- Cabergoline or bromocriptine, if you have hyperprolactinemia
If you have PCOS and other treatments aren't working for you, your doctor may suggest laparoscopic surgery called ovarian diathermy. Your doctor makes a small cut in your belly to destroy (drill) part of your ovaries. The surgery can help you ovulate again.
When should you see a doctor about late ovulation?
If you haven't had a period "in the last 35 days or more than three months ago, it's time to see your doctor," says Thalia R. Segal, MD, the founder and medical director of COLLAB Fertility in the San Francisco Bay Area.
"The bottom line is, don't ignore having irregular or delayed ovulating cycles. If you're trying to conceive, there are simple imaging and blood tests to understand the reason," says Segal. "Treatments may include pills, such as letrozole or clomid to help induce ovulation in a regular, predictable pattern."
Even if you're not trying to get pregnant, it's always good to know about your options. "There may even be supplements or dietary changes you could do to correct the underlying condition without medications," Segal says.
Your doctor can also help you know when the best time to have sex is and how often to have it. Talk to your doctor if your period is later than expected. They can help you figure out what may be going on.
Takeaways
The average menstrual cycle is about 28 days, with ovulation around day 14 of your cycle. But each person is different and with late ovulation, your ovary doesn't release the egg until after the 21st day of your cycle. Many medical conditions can cause late ovulation, such as polycystic ovarian syndrome (PCOS), obesity, too much prolactin, or even certain medications. Talk to your doctor if you have late ovulation, they can help you predict ovulation and regulate your periods.
Late Ovulation and Fertility FAQs
Does late ovulation mean a bad egg?
Eggs that are released late (during late ovulation) don't necessarily impact quality. Late ovulation can lower your chances of getting pregnant. So it's important to know the signs of ovulation and talk to your doctor about how to predict when you ovulate.
Does a late period mean late ovulation?
A late period could mean late or absent ovulation, or it may mean you're pregnant. If you've always had a regular menstrual cycle but notice your periods are starting later — or not at all — talk to your doctor. Your doctor can help you figure out what's going on and why your period is late.
What is the pregnancy success rate of late ovulation?
The pregnancy success rates can vary depending on the reason for your late ovulation. One study reported a pregnancy success rate of about 22 in 100 people who had late ovulation. Talk to your doctor about your options, your specific situation, and your fertility chances.
Does late ovulation mean a longer cycle?
Usually late ovulation means a longer cycle because your egg isn't released until 21 days in your cycle. And that can mean your cycle lasts longer than 35 days between periods. But even with a regular cycle, you have a chance for late ovulation. In fact, one study reported that with a regular cycle you have a 1%-6% chance for late ovulation.
Can you make ovulation happen sooner?
Yes, you can make lifestyle changes and take medications to make ovulation happen sooner. Try to reach your goal weight, quit smoking, avoid alcohol, and eat a healthy diet to keep your hormones well-balanced. If you have problems with ovulation, talk to your doctor. They can help you figure out what's causing your late ovulation and offer the best treatment for your health.
