Causes of Miscarriage
Definition Of Miscarriage
Miscarriage is defined as the loss of a pregnancy in the first 20 weeks of gestation. After 20 weeks, a pregnancy loss is then defined as a stillbirth. The statistics show that between 15 and 20 percent of pregnancies end in miscarriage and more than 80 percent of these losses occur within the first 12 weeks. The numbers do not include the loss of fertilized eggs before a pregnancy test is taken. Studies have shown that between 30 and 50 percent of fertilized eggs are lost before a woman even knows she's conceived. The loss happens so early she goes on to have her period on time.
What Causes Miscarriage In The First Trimester?
Between 50 and 70 percent of lost pregnancies that happen in the first trimester (first 12 weeks) are thought to be the result of random events, usually caused by chromosomal abnormalities in the fertilized egg. Either the egg or the sperm has the wrong number of chromosomes which prohibits the fertilized egg from developing normally.
Another potential cause of miscarriage is progesterone deficiency. Women with low progesterone levels in the luteal phase of their menstrual cycles (the second half), may be prescribed progesterone supplements to help in this area. However, there is no proof that using a progesterone supplement will ensure a full-term pregnancy.
Later Term Miscarriage
Up to 15 percent of pregnancy losses which occur in the second trimester may be due to uterine malformation, cervical problems, such as a weak cervix, or fibroids and other types of growths. These same conditions have been known to cause premature or early delivery. Many late pregnancy losses (third trimester) are due to problems with the umbilical cord or the placenta. Another risk for miscarriage is a multiple pregnancy, which can be very problematic for both mother and babies.
Diseases Associated With Miscarriage
One of the diseases or conditions known to affect pregnancy and cause miscarriage is uncontrolled diabetes. When a woman has out-of-control diabetes, unchecked blood sugar and insulin resistance wreak havoc with both mother and baby. Women with well-controlled diabetes are not at a higher risk for miscarriage.
Women with PCOS, polycystic ovarian syndrome, are at a 30 to 50 percent risk of miscarriage, often in the first trimester. Treatment with diabetic drugs, such as Metformin has shown positive results in helping overcome some of the risks associated with PCOS pregnancies.
High blood pressure, hypothyroidism, autoimmune diseases and certain illnesses such as rubella and sexually transmitted diseases like Chlamydia, all increase the risk of miscarriage.
Lifestyle Implications For Miscarriage Risk
It goes without saying that illicit drugs such as cocaine and heroin cause miscarriage. Tobacco smokers also have a higher risk of miscarriage, and a father who is a smoker is considered a risk factor as well. Caffeine has also been shown to create an increased risk for miscarriage. Physical trauma, exposure to environmental toxins and the use of an intrauterine device (IUD) at the time of conception all cause risk of miscarriage.