Watery Period Blood: Is It a Sign of Pregnancy?

From a young age, most women are taught that periods occur regularly: they stay for a week, give us PMS, and look more or less identical from month to month.

In reality, there’s no such thing as an “average” period. Small details vary from cycle to cycle, from the duration of flow to the texture of the blood itself. So, if your period starts to look a little thinner than usual, you might be wondering:

What’s going on here? Or even, is watery period blood a sign of pregnancy?

It’s possible. But, in most cases, watery period blood is caused by hormonal shifts—which could be an early signal for pregnancy. However, before you take a pregnancy test, there are some other possible causes behind this shift.

What makes period blood watery?

We often hear the word “bleeding” used interchangeably with the word “period.” However, menstruation is not the same as getting a paper cut.

The shedding that occurs during your period is actually a mix of blood and other biological fluids—and the composition can change with your hormones and general health

Menstrual blood contains three general components:

• Blood
• Vaginal secretions (the clear or white fluid created by your reproductive system)
• Endometrial cells (originating from the tissue lining your uterine wall)

The texture and appearance of your period’s (shall we say) output depend on the ratio of these three ingredients, as well as the timing of your period. For instance, a thicker texture may contain more endometrial matter, and a darker color could indicate older blood or tissue.

Typically, periods with a watery texture consist of:

• More vaginal secretions
• Less blood and endometrial matter
• Newer blood with a lighter color

Five Causes of Watery Period Blood

Every woman sees shifts in period blood throughout life. While a watery period might pique your curiosity when you’re trying for a baby, a lighter “crimson wave” may just be the latest tide change in the history of your period.

That said, it’s also true that pregnancy can cause implantation bleeding—light spotting that signals a fertilized egg has landed (more on this later!). But before you reach for an at-home pregnancy test, let’s talk 5 reasons why you might see watery menstrual blood.

#1 Your Period Just Began (or Will End Soon)

Many women see a range of colors and textures on the days they’re menstruating. This is largely due to the age of blood and tissue.

As a general rule, darker colors and thicker textures signal that your period blood is on the older side. The longer blood camps out in your uterus, the more time it has to oxidize and coagulate (form clumps) before it exits your vagina.

In contrast, fresher blood is less viscous and may appear lighter in color. For women, it’s completely normal to have period blood that looks:

• Light pink
• Bright red
• Dark red
• Brown
• Orange-Red

Many women start or end their period with a lighter blood flow of pinkish blood with a thin, watery texture. This indicates that “fresher,” or newer, blood and tissue are leaving the uterus.

#2 You Use Hormonal Birth Control

Hormonal birth control prevents pregnancy by altering your hormone levels. Depending on the type of contraception you use, this could leave you with a thinner uterine lining—and, as a result, a waterier period.

Women’s natural menstrual cycles follow four distinct reproductive phases across 21 to 40 days:

1. Menstruation (Days 1 to 7), when a sudden drop in progesterone and estrogen triggers the shedding of your uterine lining.
2. Follicular phase (Days 7 to 14), after your menstrual period ends, when estrogen and follicle-stimulating hormone (FSH) start to rise, stimulating the growth of a new egg.
3. Ovulation (Days 10 to 14), when estrogen reaches its peak and luteinizing hormone (LH) is disbursed to trigger the release of a mature egg.
4. Luteal (Days 15 to 28), where estrogen spikes and the empty egg follicle (now a corpus luteum) emits progesterone. If no fertilized egg implants, these hormones suddenly drop off, triggering menses and the start of a new cycle.

Hormonal contraception interrupts your monthly hormonal cycle by regulating your estrogen and progesterone levels. In doing so, it helps prevent pregnancy by:

• Arresting ovulation, which prevents the ovaries from releasing a mature egg
• Thickening your cervical mucus, which makes it more difficult for sperm to reach an egg
• Thinning the uterine lining, which makes it harder for a fertilized egg to implant

These changes to your body’s reproductive routine can lead to a lighter period (or, for some women, no period at all). If you started a new contraceptive pill or hormonal IUD, there’s a high chance it’s responsible for your ultra-light period.

#3 You Have Low Estrogen Levels

Consistently getting thin, watery, and short periods? Then you may have low levels of estrogen.

Right after your period ends, the ovaries (the twin organs that hold all of your eggs) start revving up their estrogen production. Estrogen is responsible for building up your uterine lining, making it a cushy future landing pad for a fertilized egg. If no fertilized egg implants, then your body will shed this thickened lining during the next period.

However: When estrogen levels are low, the prepare-for-baby message it sends to your uterus comes out as more of a whisper. With a thinner uterine lining, you may see watery and lighter periods, as well as symptoms like fatigue, headaches, and mood swings.

Some health factors that can diminish estrogen include:

• Aging (especially ages 45 and up)
• Eating disorders (particularly restrictive eating habits)
• Excessive exercise
• Hypopituitarism (a low-functioning pituitary gland)
• Autoimmune conditions
• Turner syndrome
• Radiation treatments

#4 You Are Approaching Menopause

Rounding the corner to your 40s? Then you might be entering perimenopause, which can bring more watery, lighter periods.

Perimenopause is the transitional stage preceding menopause, which typically sets in for a woman around your 40s. As your egg supply dwindles, your body responds by tapering off menstruation and making some changes to your monthly hormonal regimen. For many women, this results in:

• Irregular and lighter periods
• Hot flashes
• Sleep issues and insomnia
• Bladder issues
• Low sex drive
• Reduced bone density
• Decreased fertility

During this transitional period, it’s very normal for your periods to lighten in color and texture.

#5 You Have a Health Condition

A watery period on its own is usually nothing to worry about. However, a watery period accompanied by other physical symptoms may prompt a visit to a medical provider.

Many health conditions can directly or indirectly interfere with your reproductive hormones, causing a thinner or watery period. If you’ve ruled out other possible causes, a watery period may be a sign of:

• Polycystic Ovarian Syndrome (PCOS) – PCOS is known to elevate androgen levels in up to 12% of women. This can lead to an irregular or thinner menstrual period, as well as weight gain, acne, excess facial hair, and growths on your ovaries (ovarian cysts).
• Thyroid issues – Because thyroid hormones support the production of sex hormones, thyroid conditions like Hashimoto’s Disease and Graves’ Disease can lead to thin or water periods. If you experience sudden changes in appetite, weight, and energy alongside a watery period, there’s a chance it may be a thyroid issue.
• Fallopian or ovarian tumor – A tumor in your ovaries or fallopian tubes can also result in a watery period. However, tumors are usually also accompanied by persistent lower abdominal pain, cramps, bloating, and excess discharge.

Is it a watery period, or implantation bleeding?

For many women, implantation bleeding can be a dead-ringer for a light, watery period—when in reality, it’s an early sign of pregnancy!

After conception, a fertilized egg burrows in the uterine lining, creating a small rupture that can spur spotting or light bleeding. If you’re a first-time mom, it can be alarming to notice red blood in your underwear—but implantation bleeding is quite common, occurring in 1 out of 4 pregnant women.

To distinguish implantation bleeding from a watery period, you can check for the following implantation bleeding qualities:

• Light color (either rose pink or light brown)
• Minimal volume with no clots
• Short in duration (lasting a few hours to 3 days)

Curious about other early signs of pregnancy? Find additional insights into early pregnancy symptoms, including what color urine is in early pregnancy.

The tricky part between a watery period and implantation bleeding? Implantation bleeding typically occurs around the same time as your period would arrive (around one to two weeks after ovulation). If you’ve been trying for a baby and notice a conspicuously lighter flow this month, this may not be a watery period after all—it just might be your baby latching on to the uterine lining.

When it comes to understanding the differences between pregnancy symptoms and those related to your menstrual cycle, it’s also valuable to consider implantation cramps vs period cramps.

Other Period Consistency Meanings

The consistency of menstrual blood can offer insights into your menstrual health. Here are some different consistencies you might encounter:

• Slimy or Stringy: Occasional slimy or stringy blood can be normal, often linked to hormonal changes or different phases of your menstrual cycle, like ovulation.
• Clumpy or Chunky: Clumps or chunks in menstrual blood are typically bits of the uterine lining and can be normal during heavy flow. However, excessive or frequent clots might indicate underlying issues.
• Sticky or Thick: Sticky or thick menstrual blood might be due to changes in your uterine lining or hormonal imbalances. While it can sometimes be normal, persistent changes and other concerns should be discussed with a healthcare provider.
• Watery or Thin: As discussed earlier, watery blood can result from hormonal changes and is usually normal. But, if consistently excessive and accompanied by unusual symptoms, consult a healthcare professional.

When to See a Doctor

While some variations in menstrual blood are normal, certain signs and symptoms should prompt you to schedule a consultation with a healthcare provider:

• Excessive Bleeding: If your periods are excessively heavy or cause anemia symptoms like fatigue and weakness, it’s crucial to see a doctor. This could signal conditions like menorrhagia or uterine fibroids.
• Irregular Cycles: If your menstrual cycles becomes highly irregular, with frequent skipped periods or prolonged bleeding. Irregular periods can stem from hormonal imbalances, PCOS, or thyroid issues.
• Severe Pain: If you experience severe menstrual cramps (dysmenorrhea) that disrupt your daily life or are accompanied by concerning symptoms like heavy bleeding or digestive issues.
• Unusual Symptoms: Discuss any unusual or concerning symptoms related to your menstrual cycle with a healthcare professional. Sudden weight gain, severe mood swings, or changes in hair growth could indicate underlying health conditions that require evaluation and treatment.

Be Sure of The Next Sign with SneakPeek

From watery period blood to sore breasts, every physical shift can seem like a sign when you’re trying for a baby. Once you know for certain that your little one is on the way, SneakPeek is here to help you navigate some other question marks you’ll encounter along the pregnancy journey.

The SneakPeek At-Home Early Gender Blood Test is the #1 OBGYN-recommended at-home gender test for moms-to-be, with over 99% clinically-accurate¹ results that tell you your baby’s sex just 6 weeks into pregnancy. Not only can you learn your baby’s gender months before your second-trimester ultrasound, but your results are protected to ensure you and baby’s privacy as you start your journey together. SneakPeek can also help you with other pregnancy-related questions you may have, such as can you get pregnant on your period, what are the signs of twin pregnancy, how to get pregnant fast, and much more.

When it’s time to meet your new baby, join over 1 million moms who trust SneakPeek Test and get a jump start on baby planning!

This post has been reviewed for accuracy by the following medical professionals:

Dr. Heather Soper, Certified Nurse Midwife

Dr. Heather Soper brings over 15 years of experience in women's health and obstetrics to her role as the owner of The Genesis Resort for Birth. Complementing her clinical practice, she serves as an Assistant Professor of Nursing at James Madison University, where she educates nursing students with a focus on compassionate, patient-centered care. Her advanced training and dedication to midwifery are evident in her contribution to both academia and the wellness of expectant mothers.

Katie Smith, MSN, APRN, CNM

Katie Smith is a seasoned Certified Nurse Midwife and a nurturing mother to six children, offering a unique blend of professional expertise and personal experience. She is the founder of Birth Your Way Midwifery and Women’s Wellness Center in Bay County, Florida. Katie's comprehensive approach to care is informed by her hands-on experience in motherhood and her passion for empowering women through their birthing journey. Her dedication extends beyond her center as she actively engages in community wellness and family health education.

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