How to Determine Whether Miscarriage or Period

Miscarriage or Period

It can be extremely hard to tell the difference between having an early miscarriage and having a menstrual period that has come later than normal.  A normal menstrual period in most women is about 28 days in length; however, it can be shorter than that or longer than that in some women.  Both the early miscarriage and a menstrual period can be heralded by cramps, for example, so the presence of cramps doesn’t help you decide the difference between the two.

If you’re used to having extremely regular menstrual cycles and you suddenly have a cycle that is longer than 28 days, it may mean that you are having a miscarriage. The cycle is longer and the bleeding tends to be heavier than a regular period.  Any time you have intercourse around the time of ovulation, you can become pregnant and up to 40 percent of the time, the conception that comes out of the intercourse, leads to an early miscarriage.

There are some things you can pay attention to, however, that can help you in being able to tell the difference between having a heavy period and having a miscarriage. Let’s look at some of the differences, which can be extremely subtle.

A Regular Late Period

During a regular period, the first half of the cycle is identical to having an early miscarriage. The uterine lining builds up under the influence of estrogen in preparation for the release and fertilization of the egg.  At the same time, the ovaries are developing egg follicles.  At or around the fourteenth day of the cycle, one or more of the eggs is released by the ovary and travels down the fallopian tube, waiting to be fertilized by the male sperm.

In a regular period, the last half of the cycle involves the production of progesterone by the ovarian follicle but the egg degenerates.  The uterine lining matures and, after another fourteen days have gone by, the levels of estrogen and progesterone drop dramatically and a period occurs.  If the uterine lining was particularly thick during the menstrual cycle, it can be heavier than normal but usually occurs at the expected time.

Some women have cycles that are longer than average because they are late in ovulating during some or all of their cycles.  The first half of the menstrual cycle is longer than in a normal woman but the part of the cycle that occurs after ovulation is always 14 days, no matter how long the first half of the cycle was.

Other women have shorter than average cycles.  Short cycles involve a lack of ovulation in the first place. The ovary makes estrogen throughout the cycle but there is no egg released and the uterine lining does not mature.

The uterine lining builds up heavier than a regular ovulatory menstrual cycle and the bleeding tends to be heavier, with more clots and more cramping.  These cycles tend to be about 21 to 27 days in length and you can’t get pregnant during this type of cycle.

An Early Miscarriage

Any time a woman is sexually active and has sex around the time of ovulation, there is a chance that the sperm will enter the uterus and finally the fallopian tubes, where the egg is fertilized, travels down the fallopian tube and implants itself in the uterine lining.  If the implantation is successful and the woman is carrying a healthy pregnancy, the end result is the formation of a zygote, which is a fetus in the earliest stages of pregnancy.

If the egg has been fertilized, the uterine lining matures under the influence of the ovarian pregnancy follicle, the zygote implants and begins to make HCG and, on the day the woman is supposed to have her period, the zygote is making hormones that prevent the shedding of the uterine lining and the pregnancy continues.  There will be no bleeding (or slight bleeding upon implantation of the zygote); however, cramping can still occur making the woman feel as though she is going to have her period.

At some point, usually due to an abnormality in the chromosomes of the zygote/fetus, the products of pregnancy cannot keep up the hormone levels necessary to allow the pregnancy to continue and the pregnancy breaks down, resulting in a miscarriage.  A home pregnancy test may or may not be positive, depending on how healthy the implanted zygote is.  Unhealthy zygotes put out low levels of HCG, making the pregnancy test very weakly positive or not positive at all.

The bleeding that comes from an early miscarriage tends not to occur exactly on the 28th day of the cycle but instead occurs a few days or even a few weeks later.  The bleeding may seem similar to a regular period or it can be much heavier than a regular period, with both blood and tissue (representing the products of conception) passed in a menstrual period that may be longer than what the woman is used to.

The Subtle Differences you might Expect

If you are trying to tell the difference between a late period and a miscarriage, there are subtle differences that, if you are paying attention, can help you determine if what you are experiencing is a late period versus an early miscarriage. Here are some tips:

  • The Vaginal discharge will be different – If you are experiencing a late period, it will start out with a brownish-colored discharge, which represents the breakdown of old blood. The amount of flow will be about the same as with a normal period but the timing of the period is not on track with a normal period.  The brown discharge gives way to a pink and then a red discharge that may have more clots in it than normal.  If, on the other hand, you are having a miscarriage, there will be the same brown discharge but you will see a heavier flow and the presence of large clots and the presence of actual tissue that represents the zygote that has detached itself from the vaginal wall and is passed through the cervix relatively intact.
  • The degree of cramping – With a regular period, there may be some cramping and pain associated with the onset of the period and perhaps the first couple of days of the period.  The cramps go away and are usually extremely tolerable.  In a miscarriage, on the other hand, the onset of pain is sudden and the cramps are much more severe than a regular period.  The pain may be considered the worst pain the woman has ever experienced in a regular period.  Rather than having low pelvic cramps, the cramps tend to extend to the back, and onto the upper thighs. The cramps last longer than a regular period and tend to last for the duration of the bleeding.
  • Miscarriage or PeriodThe presence of back pain – The presence of back pain is not uncommon with regular periods. Usually the back pain is relatively mild and is easily managed with a nonsteroidal anti-inflammatory medication or acetaminophen.  In a miscarriage, the back pain is usually much more severe than is found in a period and the taking of NSAID medications doesn’t seem to do much to control the pain.
  • The presence of fever – Rarely does a woman have a fever with a normal period.  In a miscarriage, however, fevers are not uncommon and may represent a uterine infection as a cause of the early miscarriage.   Anytime you experience a fever along with heavy bleeding and what seems like a late period, you should see the doctor for immediate management of the probable infection.
  • The degree of blood flow – In a normal period, you can usually keep up with the flow by using tampons or menstrual pads.  If the blood flow is due to a miscarriage, however, it tends to come on more rapidly and is so heavy that tampons and menstrual pads cannot contain the flow.  The bleeding can sometimes be so severe that you need to seek medical attention for hemorrhaging.

The differences between a late menstrual period and an early miscarriage can be so subtle that you can’t tell the difference.  Taking a pregnancy test may be able to help you tell the difference between the two in some cases.


  1. Early Miscarriage Signs vs. Starting a Period.
  2. Difference between miscarriage and period.
Click Here to Leave a Comment Below
Diyah - January 6, 2018 Reply

The statement about not being able to get pregnant with shorter cycles is false. Except for a random one or so, mine haven’t been longer than 26 days in years. Even when I fell pregnant the first time, I was having 25/6 day cycles then as well, and had no issues carrying.

Carrie - January 24, 2018 Reply

Some of the information here was misinforming. Especially claiming women whose cycles are from 21-27 days don’t ovulate?? That’s very false

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