Difference Between Pregnancy Bleeding and Period

The process of pregnancy is considered to be one of awe and wonder, filled with joy, and achievements of overcoming the hardships of pregnancy. Pregnancy bleeding is a broad term, which could mean several things. As the pregnancy is divided in to trimesters (1st trimester- the first 12 weeks, 2nd trimester-12 to 28 weeks, and 3rd trimester-28 to 40 weeks), and each of these trimesters are associated with varying changes in the maternal and foetal physiology, and thus, varying pathological conditions as well. A period or menstrual bleeding is a normal physiological event in a female of the reproductive age, and it is important to know the differences so that life threatening incidents do not go unnoticed.

Pregnancy Bleeding

In the first trimester, the pregnancy bleeding may be due to miscarriage, and with or without any associated pain and passage of tissues. Other causes may be infections of the vulva, ectopic pregnancy, or molar pregnancy. The latter two are severe enough to require termination of the pregnancy. During the second and third trimesters, the bleeding maybe due to conditions such as placenta previa or placental abruption. In previa, there is a lower lying placenta, where the blood vessels are opening or partially opening in to the vaginal canal. In abruption, the placenta becomes separated from the endometrium and there can be bleeding. Both these conditions are life threatening, and require urgent assessment and management.


Period or the menstruation is a point in the hormonal, ovarian, and the uterine cycles when the development of a new egg, for possible fertilization and implantation, is marked with vaginal bleeding through the shedding of the previously developed endometrial lining, rich with blood and nutrients. This is usually without pain, but some do experience pain. The bleeding is not life threatening, but in a person who is suffering from another debilitating illness it can pose several problems.

What is the difference between Pregnancy Bleeding and Period?

Both conditions deal with bleeding via vagina in females in the reproductive age. One is physiologically normal, whereas the other one is in a physiologically altered state. Both conditions can pose problems and may require interventions.

– Pregnancy bleeding is always pathological, whereas a period is physiological.

– Pregnancy bleeding can cause displacement of blood in larger quantities, but in periods it is relatively less.

– The bleeding in pregnancy can be overt or occult, and the occult blood is altered.

– Pregnancy bleeding may or may not be associated with other symptoms like abdominal cramps, which may occur in periods as well, but the late pregnancy bleeding are associated with cardiovascular compromise, as they tend to be heavy bleeding.

– Where periods do not require any assessment, pregnancy bleeds require, proper and urgent assessment and management.

– While, periods do not affect the future pregnancies in an adverse way, pregnancy bleedings can, and they may require future follow up management as in the case of molar pregnancies.

As there are variant conditions under the heading of pregnancy bleeding, they need to be understood separately and compared with periods.

The importance of these two conditions, and understanding as how to differentiate is based on the physiology and the pathology of the individual conditions. Basically, periods are physiological and pregnancy bleeds are pathological, occurring in a person with altered physiology.