The theory about this that makes most sense is called Trophotropism. The easiest way to explain this is to make a comparison to a plant. A plant will lean towards the sun to get the light it needs to survive. Since the lower segment of the uterus is not as nourishing as the upper segment, the placenta will grow to reach more nourishing tissue. The placental mass will erode away from the cervix, but the vessels can't. This also explains the velamentous insertion of the cord.

Possibly. Unlike a placenta previa the vessels involved in a vasa previa are unlikely to erode away (which is how a placenta previa seemingly "moves"). There is a chance that this vessel will become thrombosed (plugged). This would take away the risk of fetal bleeding, but whether the baby would tolerate this depends on what proportion of the blood flows through this vessel.

Most likely the transverse lie is related to the low-lying placenta. When the placenta occupies the lower portion of the uterus, it prevents the head from engaging (going into the lower segment of the uterus, and the pelvis). Therefore, the baby may not be head first. The position of the vasa previa baby may also reflect an attempt by the baby to avoid compression of the velamentous vessels.

Vasa previa does have an association with a low-lying placenta, which may be associated with previous uterine surgery including prior cesarean, maternal smoking, multiple pregnancy (twins, triplets, etc), and also with assisted conception (artificial insemination, in-vitro fertilization, etc).

Published data on vasa previa mortality shows a rate of 30-100%. Data suggests that survival is practically 100% if the diagnosis of vasa previa is made prenatally, and the patient is delivered by elective cesarean section. We have 2 prenatally diagnosed babies on record that died. However, they died of other complications of pregnancy such as prematurity and placenta previa. Vasa previa can be diagnosed prenatally. The time has come when physicians should look actively for it.

With a vasa previa not associated with abnormal placental implantation (some form of placental previa) there should be no increase in third trimester bleeding. Bleeding from a vasa previa only occurs if the vessel is torn or ruptures. No. There is nothing that we actively do to stop bleeding from a placenta previa. Bleeding from a placenta previa occurs because the attachment of the placenta to the uterus breaks (peels off).

Yes, velamentous cord insertion is also dangerous when the unprotected blood vessels are not crossing the cervix.

The answer to this is unknown. There are no lifestyle changes that affect the incidence of vasa previa. However, vasa previa does have an association with a low-lying placenta, which may be associated with prior cesarean, maternal smoking, multiple pregnancy, and also with assisted conception.

Though it is common to deliver with a VCI without detriment to the baby, VCI carries risk even when not a vasa previa. VCI may be allowed a trial of labor if the vessels are away from the cervix. However, close continuous monitoring is mandatory. The vessels could rupture, and also pressure on the vessels could lead to fetal compromise. This can be detected early by monitoring.

BSE was first observed in Great Britain in April 1985 and was officially diagnosed in 1986. By June 1990, some 14,000 cases were confirmed (out of an estimated population of 10 million cattle) in Great Britain. Since 1986, more than 185,000 cases of BSE have been confirmed in Great Britain. The epidemic peaked in 1992-93 at almost 1,000 new cases per week. Control measures have since reduced incidence of the disease, and currently fewer than 100 new cases are reported per week.

Fistula occurs when emergency obstetric care is not available to women who develop complications during childbirth. This is why women living in remote rural areas with little access to medical care are at risk. Before the medical advances of the 20th Century, fistula was quite common in Europe and the United States. Today, fistula is almost unheard of in high-income countries, or in countries where obstetric care is widely available.

In 2007, there are approximately 2 million people with limb loss in the United States (excluding fingers and toes). There are more than 185,000 new amputations preformed each year in this country. The prevalence rate in 1996 was 4.9 per 1,000 persons. The incidence rate was 46.2 per 100,000 persons with dysvascular disease, 5.86 per 100,000 persons secondary to trauma, 0.35 per 100,000 secondary to malignancy of a bone or joint. The birth prevalence of congenital limb deficiency in 1996 was 25.

Sound enters your ears in sound waves. These sound waves hit your eardrum and are converted to pressure changes in the inner ear. This causes special nerves to impulse, which are read by your brain as sound. When these nerves are exposed to a surplus of pressure changes, they may become damaged. You may have noticed that if you listen to loud music for several hours that your ears "ring." This is a Temporary Threshold Shift, or a temporary reduction in hearing.

Conception, or fertilization, occurs when the male's sperm meets with the woman's ovum (egg) and successfully penetrates it. This typically takes place in one of the woman's fallopian tubes and the fertilized egg then travels to the uterus and implants in the uterine lining. For pregnancy to take place, fertilization of the egg must be followed by a successful implantation. Only one egg is released for fertilization in each menstrual cycle.

Your body has a natural defense system called the immune system that protects you from infection and disease. The immune system defends your body by producing "killer" cells that destroy foreign substances (such as viruses and bacteria). Since the donor organ doesn't match your old organ exactly, your body tries to destroy the transplanted organ. Essentially, a transplant creates a new disease called rejection. Rejection is nature's way of protecting your body.

Almost everyone is exposed to low levels of asbestos in their lives. It exists in the air at extremely low concentration; levels are highest in urban and industrial areas. These fibers are released into the air during demolition work, remodeling, or other activity in which the material containing asbestos is disturbed. Asbestos may occur in tap water where such water passes through cement pipes containing the substance.

Preeclampsia can appear at any time during the pregnancy, delivery and up to six weeks post-partum, though it most frequently occurs in the final trimester and resolves within 48 hours of delivery. Preeclampsia can develop gradually, or come on quite suddenly, even flaring up in a matter of hours, though the signs and symptoms may have been present for months undetected or unnoticed.

Child abuse occur in the place where it is least expected; home, and from adults entrusted for the care of children; parents or guardians. In many cases, if the abuser is not a parent/guardian, s/he is certainly known to the child, especially in the case of sexual abuse.

Piles (hemorrhoids) are common in both men and women. By the age of 50 half of the people develop hemorrhoids to some extent. Although bleeding may occur in some cases, it does not cause any serious problem. But a person suffering from long standing bleeding piles (hemorrhoids) can have anemia. Women usually tend to develop piles (hemorrhoids) during pregnancy because of the pressure of the fetus and hormonal changes, but it is usually a temporary problem and disappears after childbirth.