Ovulation & Pregnancy: What You Need to Know

Medically reviewed by Dr. Melissa Dennis, MD, MHA, FACOG

Ovulation occurs when an egg is released from the ovary and begins to travel down the fallopian tube. For couples who are trying to conceive, tracking ovulation is a key part of fertility planning. By using ovulation tests, observing your symptoms, and monitoring your cycle, you can increase the chances of successfully getting pregnant during each fertile window.  

Ovulation Testing

Ovulation tests work by detecting the presence of luteinizing hormone (LH) in your urine. LH levels dramatically increase before ovulation; when an LH surge is detected, you know that ovulation is likely to occur within the next 12-36 hours. Using an ovulation test can help you determine when ovulation is imminent, which is a crucial time to engage in intercourse if you are trying to conceive. 

At first glance, ovulation tests may look similar to pregnancy tests: both come as digital tests or indicator strips, which are typically more affordable. You can buy ovulation tests at most pharmacies or drug stores in the family planning aisle. 

To take an ovulation test:

1. Urinate directly onto the test, or into a clean, dry cup, and then dip the tip of the test into your urine
2. Gently shake off excess urine after the tip has been fully saturated
3. Wait 2-3 minutes for the result to be ready

Testing processes vary by ovulation test brands and test type, so be sure to read the package insert for full instructions. 

How to read an ovulation test 

There are two types of common ovulation tests:

• Digital ovulation tests: Clearly indicate results on a digital screen. A positive test will read “Yes” or display a smiley face if a surge in LH is detected.
• Strip ovulation tests: Display lines that must be interpreted.
  
  • A positive strip test: Indicated by a test line as dark as or darker than the control line.
  • A negative strip test: Indicated by the test line being absent or lighter than the control line.
  • An invalid strip line result: If a control line does not appear, the test is invalid.

There are several reasons why an ovulation test may produce an invalid result, including having a faulty strip. Before taking the test, be sure to check its expiration date, since an expired test may result in an invalid result. Test results may also be invalid if you have been drinking a lot of water and your urine is diluted, making it harder to detect the hormone levels present. Ovulation tests are also designed to be interpreted within a specific window of time; if you’re reading the test outside of that window, the result may be invalid. 

When to take an ovulation test 

The best time to take an ovulation test is typically in the afternoon or early evening. While LH surges often begin in the morning, it may take several hours for the hormone to appear in your urine. If you are still learning your cycle, there is no harm in testing twice per day to ensure that you don’t miss the surge.

When tracking your cycle, day 1 is considered the first day of your menstrual period. Ovulation always happens 14 days before menstruation, which is typically around the midpoint of the cyle. If you have a 28 day cycle, this means ovulation occurs on day 14; if you have a 34 day cycle, ovulation occurs on day 20. To accurately detect your fertile window, start taking ovulation tests a few days before you expect ovulation at to occur. Testing at the same time each day will improve accuracy and help you recognize patterns in your cycle. 

Will an ovulation test be positive if you're pregnant? 

Ovulation tests are not designed to detect pregnancy, but in rare cases, they can give a false positive result. This is because both LH and the pregnancy hormone hCG share similar molecular structures. While an ovulation test may turn positive if you’re pregnant, a dedicated pregnancy test is far more reliable for confirming pregnancy.

Ovulation Symptoms

Your body may show several signs when ovulation is near, often influenced by hormonal changes. Common symptoms include:

• Bloating
• Nausea 
• Increased sex drive
• Emotional changes
• Abdominal or pelvic pain (known as mittelschmerz)
• Tiredness
• Sore or tender breasts 

Changes in cervical mucus are another important clue, as it typically becomes clear, stretchy, and resembles egg whites when you’re most fertile. Paying attention to these cues can provide valuable insight into your fertile days.

Ovulation & Bleeding

Why am I bleeding during ovulation? 

Bleeding or spotting during ovulation can happen for a variety of reasons, often linked to hormonal changes, especially in progesterone, or other underlying conditions. For some, light pink or brown discharge may occur when the follicle releases an egg, causing a small amount of blood as the ovarian wall ruptures.

Implantation bleeding occurs later in the cycle, when a fertilized egg attaches to the uterine lining, and this can sometimes cause light spotting that can be mistaken for ovulation bleeding, or a light and slightly early period. Tracking your cycle and symptoms can help you decide if the bleeding is ovulation, implantation, or menstrual related.

Is it normal to spot during ovulation? 

While light bleeding during ovulation is often harmless, it’s important to be aware of other potential causes. More concerning causes include ectopic pregnancy, where a fertilized egg implants outside the uterus, or pelvic inflammatory disease (PID), an infection that can cause inflammation and spotting.

In some cases, spotting could indicate a sexually transmitted infection (STI) or other condition that requires medical attention. If you experience heavy bleeding, persistent spotting, or other unusual symptoms, it’s important to consult your healthcare provider for evaluation. Monitoring your symptoms and sharing your observations can help identify any concerns early.

Ovulation & Luteinizing Hormone

Luteinizing hormone (LH) plays a vital role in ovulation, making it an important marker for fertility tracking. LH triggers the release of the egg, which is why identifying its peak is key.

How long after LH peak is ovulation? 

Ovulation generally occurs 12-36 hours after your LH peak. This window is your most fertile period, so tracking your LH surge with ovulation tests can help you identify when to have intercourse to improve your chances of conception.

What LH level indicates ovulation? 

Most ovulation tests show a positive result when LH levels reach 25-40 mIU/mL. However, some individuals may have naturally higher or lower baseline LH levels, so understanding your unique patterns can improve accuracy.

How long does LH stay elevated after ovulation? 

LH levels drop within 24-48 hours after ovulation as the luteal phase begins. During this phase, the corpus luteum produces progesterone to support a potential pregnancy. If fertilization doesn’t occur, progesterone levels will eventually fall, and your menstrual cycle will start again. Tracking LH alongside body temperature and physical symptoms can help confirm ovulation and identify your fertile window.