Possible Causes of Miscarriage
Miscarriage, sometimes called spontaneous abortion, is when a pregnancy ends on its own before the still-forming child is able to survive on its own. A spontaneously ended pregnancy before 24 weeks is typically considered a miscarriage, but miscarriages occur more often within the first 12 weeks of gestation. Often there's little a woman could have done to prevent the miscarriage so no woman should ever feel it's her fault if her unborn baby died.
Many times doctors don't know why a miscarriage occurred. Other times there's educated guesses as to the possible causes of miscarriage. Here's a brief look at some.
Many early miscarriages happen when a fertilized and implanted egg develops a placenta and membrane but no embryo. The egg is called a blighted ovum. The body typically senses there is something wrong with the egg and will spontaneously remove it. Some doctors suspect that about 50 percent of miscarriages before 12 weeks are blighted ovums.
Unlike a blighted ovum, molar pregnancies are highly uncommon. Statistics indicate that a blighted ovum occurs in 1 in 1,000 pregnancies. In a molar pregnancy there's a problem with the development of the placenta where it grows into a mass of cysts inside the uterus. Sometimes the placenta contains and embryo; sometimes it doesn't. If there is an embryo, the embryo dies because the placenta can't sustain it.
Sometimes an embryo dies because of genetic abnormalities not easily noticed with an early ultrasound. It's not uncommon for the embryo or fetus to die before any signs of a miscarriage or pregnancy loss have occurred. This is called intrauterine fetal demise.
Collagen Vascular Diseases
Women with these types of diseases create antibodies to their own body tissue including the developing tissue of their unborn children. These diseases make it difficult for the woman to stay pregnant and can also have potentially serious health consequences when the woman isn't pregnant. Antiphospholipid antibody syndrome and systemic lupus erythematosus are examples of collagen vascular diseases.
Abnormal Uterine Structure
Some women have a tissue bridge (uterine septum) that divides the uterine cavity into sections making it difficult the carry a baby to term. There's no room for the growing child. The septum also has a very poor blood supply which doesn't provide enough nutrients for placental growth which can cause a miscarriage.
Benign growth of muscle cells, called fibroid tumors, can interfere with the blood supply needed to create a healthy placenta for a developing embryo which can cause a miscarriage.
As a woman grows older, her chances of a miscarriage increase. Excessive trauma like a serious accident or bad beating can cause a miscarriage. Some lifestyle choices or experiences like drug abuse, alcoholism or exposure to toxic substances or radiation can increase the chances of a spontaneous abortion.
As the pregnancy progresses, the weight of the growing child puts pressure on the cervix beginning at about 13 weeks. Some women have a weakened or incompetent cervix that begins to open when this happens. If not treated or not discovered, this can cause a miscarriage past the first trimester.