Spontaneous miscarriage is a term which describes the spontaneous cessation of pregnancy up to the 20th week of pregnancy.
Up to 10-20% of all pregnancies may end in miscarriage.
Furthermore, about 2% of couples experience recurrent miscarriages (about 3 or more miscarriages) 
“Chemical pregnancies” make up about 50-75% of all miscarriages. This is a situation which occasionally takes place without the woman’s knowledge when the pregnancy is lost immediately after implantation and leads to bleeding, which she assumes is her period.
Most spontaneous miscarriages take place up to and including the 13th week. There are several reasons a miscarriage might take place:
Low levels of progesterone following a weakness in the corpus luteum which does not produce the correct levels of progesterone. Usually, in women with this problem, the time period between ovulation and menstruation will be short. The functioning of the corpus luteum can be determined through a progesterone blood test. Problems with the thyroid gland can also influence the ability to carry to term and cause miscarriage.
The uterine structure or uterine malformations can interfere with fetal development and cause miscarriage. Diagnosis through uterine imaging or hysteroscopy can determine if this is that situation which is causing miscarriage. Occasionally, there may be cervical insufficiency, for which the standard treatment is cerclage, or stitching of the cervix.
Chromosomal defects become more common as the woman’s age rises. Usually, the problem stems from a flaw in the ovum or the sperm which causes the process of cell division to go wrong, creating a defect in the chromosomal structure, and the embryo does not survive. Chromosomal defects can also be the reason for discovering an empty gestational sac containing no embryo, either because the embryo wasn’t created at all or because it ceased developing at a very early stage, in which case the recommendation is to terminate the pregnancy through dilation and curettage.
Some women develop antibodies which attack the embryo and prevent its development. These antibodies lead to the formation of clots in the blood vessels leading to the placenta and interfere with the development of the embryo.
Natural miscarriage can be caused by infection. Usually, this is a one-time occurrence in which the mother contracts the infection at the earliest stage of the pregnancy. Infections such as chlamydia, CMV, and genital herpes could increase the chance of miscarriage; therefore, it is important to test before becoming pregnant and to treat in the event that an infection exists in order to prevent miscarriage.
Blood Clotting Factors
The problem of blood clots can be divided into congenital and acquired causes.
Among the congenital causes include situations like Factor II mutation (also called Prothrombin 20210 mutation), the Factor V Leiden (FVL) mutation, Protein S or C deficiency, MTHFR enzyme defect and more.
Among the acquired causes include, the presence of lupus anticoagulant (LAC), and Antiphospholipid Syndrome (APS), which I’ll expand on a little here:
APS is a situation in which antibodies develop against clotting-system proteins (APLA) which cause excess clotting. This disease can be primary or secondary to lupus and various connective-tissue diseases. Between 2% and 12% of the healthy population will present with these antibodies. Although the presence of APLA antibodies is clinically connected to this syndrome, it is still not known with certainty whether they are directly connected in creating the syndrome or whether they appear secondary to it. The clinical symptoms of APS include thromboses (DVT), stroke, anemia, decreased platelets, skin problems, recurrent miscarriages, and more.
About 15% of all the reasons for recurrent miscarriages occur following this syndrome. The existence of these antibodies can cause:
- Problems in blood flow to the placenta ultimately causing fetal death (IUFD)
- Early pregnancy blood pressure
- Fetus below the 10th percentile in weight for pregnancy age (IUGR)
The usual treatment can include anti-clotting medications such as injections of enoxaparin sodium and Coumadin (Warfarin). There are reports that in women with recurrent miscarriages who take these medications during the course of pregnancy or even prior to pregnancy, experience from 40% to 70-80% improvement in the number of healthy births. Additional medication recommendations for this situation include steroids and immunosuppressive medications. It should be noted that for people with this syndrome, it is recommended to avoid the following:
- Prolonged periods lying down
- Lengthy flights
- Cigarette smoking
- Taking contraceptive pills
- Taking hormone substitutes