Abortion: Definition and Statistics

Definition

Abortion is defined as an interruption or threat to interrupt, a pregnancy with or without complete expulsion of products of conception before period of viability. The period of viability is defined as the period before which a baby cannot survive out the uterus. With advances in neonatal care, in many developed countries it is possible for a baby born after 24 weeks of pregnancy to survive, hence in these countries 24 weeks is the arbitrary cut off. In developing and under developed countries this cut off is taken as 28 weeks. However the author's opinion is that 28 weeks is a much more reliable and efficient cut off to maximise outcome while at the same time averting a disproportionate use of resources especially in a resource crunch setup.

Types

The following types of abortion are described:

· Complete Abortion: This is an interruption to pregnancy with complete expulsion of products of conception (POC). This will usually require no further management.

· Incomplete Abortion: This is an interruption to pregnancy with incomplete expulsion of POC. This condition often necessitates surgical procedures like D&C.

· Missed Abortion: This is an interruption of pregnancy with retained products of conception. There is usually no visible bleeding and this condition is often diagnosed by routine USG or other symptoms like lower abdominal pain. This will require surgical evacuation of the POC.

· Threatened Abortion: This is a threat to interrupt the pregnancy. The pregnancy is still viable and can be salvaged with appropriate measures. The author recommends that any bleeding in pregnancy other than just mild spotting should be considered as a threatened abortion and treatment instituted to maximise outcome.

Some Statistics

About 12 -15 % of all pregnancies end in an abortion. In many cases the abortion is so subtle that women may not even notice it or may consider it as normal periods. However this scenario is becoming rare with the widespread availability and use of home pregnancy kit.

Chemical pregnancy is the term given to such cases where the only evidence of pregnancy is the presence of HCG in the blood, which goes down as soon as the woman aborts. In these cases the pregnancy is lost immediately after implantation. A late period may be the only sign of abortion in such cases.

In US alone about 670,000 abortions happen each year, mostly during the stage of chemical pregnancy itself.

Abortion is most common in the first trimester (First 12 weeks), becoming less common as pregnancy progresses.