Difference Between Miscarriage and Period

It is very difficult to differentiate between an early miscarriage and a period that has come later than usual. Every woman has her monthly cycle at an interval of 28 days. In some the interval may be shorter and in others it may be longer. However the cycle or bleeding comes almost at the same time every month. In case the cycle is delayed by 1- 2 weeks, a pregnancy can be suspected especially if the woman is sure that she had had an intercourse during her ovulation time. In such instances if heavy vaginal bleeding occurs, it can pin point towards a miscarriage. There are certain signs that can help differentiate between a miscarriage and a heavy menstrual flow. Let us try and understand them.

Normal menstrual cycle and Pregnancy

A woman in the reproductive phase undergoes certain hormonal changes every month which is known as the menstrual cycle. The ovary produces the ovum or the egg that is released into the fallopian tube. Here it waits for the sperm to fertilize it. This is called as the ovulation phase of the cycle which falls between 12-14th day of the cycle. Simultaneously the uterus prepares itself for an anticipated pregnancy by increasing the thickness of the endometrial lining.

If a sexually active female has intercourse during this ovulation phase, there are chances that the sperm may enter the vagina and swim towards the ovum to fertilise it. When the sperm fertilises the ovum, zygote is formed which then implants itself into the thickened vaginal wall.  A woman will experience no menstrual flow after the 28th day as the pregnancy has been established. A home pregnancy test done approximately 2 weeks after the missed period will confirm the pregnancy. Sonography done around 7-9th week may show a small foetal sac and pick up heartbeat.

In case the woman has not had any sexual contact, there is no pregnancy; the endometrial lining begins the process of shedding. The unfertilised ovum and the extra endometrial tissue are then released from the body around the 28th day of the cycle in the form of normal vaginal flow that lasts for 3-5 days. After which the cycle begins again.

What happens in a miscarriage?

When the pregnancy terminates before 20 weeks it is known as a miscarriage. Most pregnancies terminate around 6 to 11 weeks when the foetus is very small. Many women are not even sure whether they are pregnant. At times due to certain chromosomal abnormalities the foetus is not strong enough to last for the whole 9 months and so dies early. The body sheds of this dead foetus and other pregnancy related tissue of the uterus in the form of blood flow through the vagina. If the woman knows that she was pregnant (confirmed by a home pregnancy test and pelvic ultrasound) and then experiences this unaccepted flow, she is sure it is a miscarriage. But if the woman hasn’t undertaken a pregnancy test and experiences late menstrual flow (delayed by 2-4 weeks), there is always a doubt whether it is a miscarriage or a late period.

Subtle differences between a miscarriage and a delayed period

  • Colour and consistency of vaginal discharge: A delayed period will be brownish red colour indicating old blood. The flow and colour of the discharge is similar to the regular menstrual flow. On the other hand the flow of a miscarriage will start with a brownish discharge followed by bright pink or red discharge which is unusually heavy with bigger clots than usual. The duration of heavy flow may continue for 2-3 days during which big red clots or small kidney shaped greyish tissue mass may also be seen. If the pregnancy has advanced beyond 6-8 weeks, the woman may also notice a ball shaped sac containing the foetus.
  • Nature of pain and cramps: Every woman experiences a bit of pain and uneasiness around her abdomen, thighs and legs just before the start of her periods. They reduce or disappear with the beginning of menses. They are usually tolerable. In some cases a woman experiences severe pain during every cycle that disappears after the bleeding ends. This indicates normal period. During a miscarriage however, there is sudden onset of pain and cramps which are unbearable. The woman may never have experienced such pain during her regular periods. The cramps come on suddenly and spread from the abdomen into the legs and thighs. The period of severe cramps is associated with very heavy blood flow. They are for a short time after which their severity subsides.
  • Severe low back pain: Every woman experiences pain and discomfort in the lower back just before the start of her periods. This is common and tolerable and is relieved by rest. In a miscarriage the woman experiences severe back pain that accompanies intolerable cramps and heavy blood flow that is not relieved on lying down.
  • Fever like symptoms: fever is not a common phenomenon during regular menstrual flow. During miscarriage a woman may feel an increase in temperature which may be an indication of internal infection. This required immediate medical attention.
  • Unusual blood flow: A normal menstrual flow is contained within pads or tampons. The blood flow in during a miscarriage is voluminous and sudden. Many women have experienced the floor getting stained bright red and blood trail from the bed to the bathroom as if a blood filled balloon has just burst.

A pelvic ultrasound and blood HcG tests are two ways to determine if there was a pregnancy in case of any confusion. The ultrasound may reveal and empty sac or show other products of conception. The level of HcG in the blood may be elevated if there had been a pregnancy. These two lab tests can help differentiate between a delayed period and an early miscarriage with more certainty.