Miscarriage
One of the most difficult things a woman can perhaps experience is the loss of a fetus. But it is an occurrence experienced by many women who conceive. The statistics are sketchy, but most cited references confirm that 10 to 25% of pregnancies result in a miscarriage. But perhaps the more painful experience is to lose an unborn child more than once.
Causes for miscarriage
Anatomical Reasons:Sometimes a woman's uterus is built in a way that makes a successful pregnancy a difficult if not impossible task. Abnormal uterine shape or weak cervixes are predominant anatomical causes that lend to recurrent miscarriages. In some cases, uterine abnormalities may be treated by surgery.
Chromosomal Abnormalities: Doctors are increasingly able to identify chromosomal abnormalities with the fetus that prevent it from developing beyond a certain stage resulting in the miscarriage or abortion of the fetus. These chromosomal abnormalities might be derived from the mother or the father and even though fertilization occurs, this abnormality prevents the fetus from growing beyond a certain stage.
Hormonal Causes: Various hormones including progesterone play a key role in the fertilization process and in the development of the embryo. Low levels of progesterone have been noted to cause recurrent miscarriages. Certain disorders such as Polycystic Ovarian Disease create an imbalance in the body's hormones and have been known to have an adverse effect on fertility and pregnancy. Various thyroid-related disorders may also contribute to recurring pregnancy loss.
Immunological Causes: Our immune system is built to protect our bodies from foreign and harmful elements. Sometimes, this system does not function in out best interest. Recurrent miscarriages have been caused by a woman's immune system that treats a growing fetus as a harmful foreign body and destroys vital tissues in the uterus, resulting in a miscarriage. Also, blood clotting issues due to excessive anti-phospholipid antibodies in the bloodstream contribute to recurring miscarriages.
Other reasons that may contribute to recurrent miscarriages include maternal age, lifestyle choices such as heavy smoking and drinking, drug abuse, diabetes, and exposure to X-rays or chemical/industrial toxins.
Acardia
Acardia is a rare and serious malformation that occurs exclusively in monizygous twins - twins developing from a single egg. Acardia represents one of the most severe and rare congenital anomalies. It is characterized by the absence of functioning heart. Acardia results from the artery to artery connections in the placenta, thereby causing a physically normal fetus to circulate blood for itself as well as a severely malformed fetus suffering from heart regression. In other words, fetus acardius is a parasite and it receives blood supply from the donor twin. Because the pump twin heart has to pump for two, there is a high risk of going into heart failure and this would lead to the death of the normal twin.
The most common variety is the acardius acephalus where the head is lacking and so are the upper extremities. Other types are acardius anceps, acardius acormus and acardius amorphous. While in acardius anceps, the most highly developed form, a partly developed head with remnants of cranial bones and brain tissue are present with developed body and extremities, acardius acormus is the rarest form of acardia. The monster is a head without a body. Acardia amorphous is the least developed monster not recognizable as a human form, with minimally developed visceral organs. Since there is no gross human form, the name acardius amorphous.
As to the cause of acardia, the etiology of acardiac monster is still unknown. Genetic defects have been reported to be the cause. Some researchers suggest chromosomal abnormalities to be the reason. Krause and Bejdl suggest that compression of the cephalic pole of the embryo prohibiting curving and fusion of the primitive heart tube to be the basic cause of this anomaly. As a result, the dependant entodermal organs like thyroid, oesophagus, trachea, lung, liver and others are also not formed.
A pregnant woman carrying an acardiac twin is unlikely to have any unusual symptoms. An acardiac twin is often found incidentally on prenatal ultrasound. As no two acardiac twins are formed exactly alike, they may present differently. Several improved imaging techniques like 2D ultrasonography, 3D ultrasonography and transvaginal Doppler ultrasonography have made diagnosis of acardia possible even in the first trimester of pregnancy. Such early diagnosis helps to reduce the risk of complications. Fetal echocardiography is also recommended to assist in early detection of heart failure in the normal twin. Chromosome studies are also done on both fetuses.
One line of treatment is watching for the earliest signs of heart failure in the pump twin with frequent ultrasounds. If heart failure is identified and the pregnancy is also far enough, then the pump twin should simply be delivered. Physicians recommend prenatal interruption of the blood vessel connections before heart failure develops in the pump twin, thus sacrificing the acardiac twin.
Specialists use laser, electrical cauterization and electrodes, serial amniocentesis, medications and other treatments successfully. If the acardiac twin is large enough and the amount of blood flow to it can cause heart failure in the healthy twin, then blood flow is stopped with Fetal Image-Guided Surgery. The acardiac or parasitic twin never survives, as it is severely malformed and does not have a functioning heart. The normal twin is at risk for heart failure and complications associated with premature birth. The normal twin is expected to have about 10% risk for malformations.
Spontaneous Abortions
Spontaneous abortion occurs when there is loss of fetus during fetus. Spontaneous abortion or miscarraige happens due to natural events and must not be confused with an elective abortion. Typically, most spontaneous abortions take place during the first trimester. Usually a miscarriage occurs anywhere between 7 - 12 weeks of pregnancy. It can even occur before a woman realises that she is pregnant. Spontaneous abortion can occur due to infection, trauma, immune response by the body or other conditions such as diabetes. The risk of such miscarraige is higher in women who are above 35 years or suffering from systemic conditions such as thyroid or diabetes. Endocrine factors such as Hypothyroidism, hypoprolactinemia or polycystic ovarian syndrome can bring on a spontaneous abortion. Chromosomal abnormalities, sexually transmitted diseases or immunological reactions can trigger a miscarraige.
A woman may experience vaginal bleeding that may contain tissue or clots. There is low back pain or abdominal cramps. Other symptoms of impending miscarraige are fever, headache and high blood pressure. Blood tests to check levels of HCG (human chorionic gonadotropin) are done. An ultrasound helps in confirming whether there has been a spontaneous abortion or not. It can detect the presence of a live fetus and fetal heart beat. It is essential to consult the healthworker when such symptoms are noticed. Not all bleeding in the first trimester leads to spontaneous abortion.
In cases of threatened abortion, the expectant mother will be advised complete bed rest. In some women, an incompetent cervix can lead to a threatened abortion. In such cases, a suture is placed around the cervix to close the cervical canal. But this has to be closely monitored. Environmental factors such as smoking or contracting rubella can threaten a pregnancy. Women who have had repeated miscarriages need to be tested to identify the cause. This may involve genetic testing of the partners and inspection of the uterus and cervix.
Bibliography / Reference
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