The statistics concerning miscarriages are startling. While many people believe miscarriages are rare events, they are actually quite common. It is estimated that approximately 25 percent of all women will have a miscarriage at some point in their lives, and sadly, some women will experience more than one. Even more shocking is the fact that about 50 percent of all pregnancies end in miscarriage. A woman's probability of having a miscarriage increases as she ages, moving from 25 to 30 percent when she reaches 40 years of age.
Miscarriages are most common during the first trimester of pregnancy, which is the first 12 weeks. When a miscarriage occurs during the first trimester, it is referred to as an early miscarriage. Sometimes miscarriages happen in the second trimester, but they are far less common. When they do occur during this time, they are called late miscarriages.
There are some risk factors that make a woman more likely to miscarry her unborn child. These include such things as smoking, drinking, and using illegal drugs during pregnancy. Certain STDs can lead to miscarriage, as can other types of infections. Other medical conditions can lead to miscarriage as well, including thyroid disease and diabetes; autoimmune conditions, such as lupus, also increase a woman's risk of miscarrying. While a woman can have these risk factors and still deliver a healthy baby, these things simply make it less likely that she will carry her child to term.
Often, there is no forthcoming explanation for why a woman has a miscarriage; this is particularly true when it occurs in the first trimester. In some cases, a doctor may examine the fetal tissue to figure out why the miscarriage occurred. More often than not, however, this doesn't happen, especially when it is a woman's first miscarriage; instead, most women never learn what caused their miscarriages. This can be particularly difficult for a woman to deal with emotionally. When the problem is unexplained, the loss of a child can seem even more senseless.
Some doctors believe that abnormal chromosomal development is the most common cause of miscarriages that occur in the first trimester. They estimate that about 70 percent of early miscarriages result from defects that involve chromosomes. Every person is supposed to have 23 pairs of chromosomes, and they're responsible for a wide range of functions and physical characteristics in the human body. Sometimes, a baby's cells split improperly, and the wrong number of chromosomes are developed, leading to a range of problems, including such things as molar pregnancy and placental issues. Sometimes, the body expels an improperly developing fetus via a miscarriage as a way of rectifying these issues.