A miscarriage is when a foetus dies in the first 20 weeks of the pregnancy. A miscarriage that occurs within the first 12 weeks of pregnancy is called first trimester miscarriage – 8 out of 10 miscarriages happen in the first 3 months. Miscarriages that occur after 12 weeks of pregnancy but before 20 weeks is called second trimester miscarriage.
The sheer number of miscarriages are high making it a common occurrence, but it being common does not in which way make it easier for the expecting parents.
Causes for the first and second trimester miscarriage are very different. First trimester miscarriages are common, with one in every five pregnancies ending in miscarriages. Once again this can be because of many reasons and it is regardless of whether the pregnancy is natural or IUI/IVF.
So, what are the most common causes of miscarriages?
While sometimes it is not easy to determine a definitive cause, a very common reason is when the embryo is chromosomally abnormal. 90% or nine out of ten miscarriages in the first trimester is due to a chromosomal abnormality. Miscarriage is a body’s way of rejecting or removing an abnormal pregnancy. Chromosomal abnormalities become more common or prevalent as a woman’s age increases, making the chance of a miscarriage higher as a woman’s age increases compared to someone who is about 25 or 30.
While “Chromosomal abnormalities” is the most common reason for most pregnancies miscarry in the first trimester (12 weeks of gestation), there are other reasons that need to be investigated as well. One should refer to a fertility specialist early on for further advice and management.
However, a miscarriage is not caused by something the pregnant person did and normal activities such as exercise, working or even having sex does not cause a spontaneous miscarriage.
Now that you are aware of some of the common reasons, here are some of the common medical terminologies used…
Threatened miscarriage – There is vaginal bleeding with mild cramps, though the cervix stays closed. There is a very high chance that as long as the baby is viable and bleeding is minimal usually it settles well without untoward consequences.
Incomplete miscarriage –Some of the pregnancy tissue comes out of the uterus while some stays inside, this requires a need follow-up treatment to remove the remaining tissue.
Complete miscarriage – All the pregnancy tissue comes out of the uterus, and extra treatment is usually not needed for this.
Missed miscarriage – This occurs when the ultrasound shows an embryo without a heartbeat or an empty pregnancy sac without an embryo. There is usually no cramps or bleeding but you may need treatment.
We hope this information is helpful. For a more detailed discussion, Book Appointment here.
DR.S.VYJAYANTHI, MD, DGO, DNB, MRCOG, MSc (Embryology, UK)
Head of Department and Consultant Fertility Specialist