Getting pregnant is not always easy, and actually fertility in humans is usually low (only 17% of women with male partner, both without fertility issue, get a pregnancy every month).
Embryo implantation in the uterus is just the first step of a process that sometimes ends abruptly because of a miscarriage or fetal loss.
Most miscarriages happen during the first trimester of pregnancy, so from that moment, the probability of a successful outcome increases significantly.
Causes of miscarriage
- Embryonic genetic anomalies. 50-70% of miscarriages during the first 3 months of pregnancy have a genetic cause. Typically, they are chromosomal issues, so numerical chromosomal abnormalities (there are a higher or lower number of chromosomes) or structural chromosomal anomalies (a piece of chromosome is missed: deletion, a piece of chromosome originally belonged to another one: translocation, a piece of chromosome is inverted: inversion, etc.). Chromosomal abnormalities are created mostly “de novo”, so they are not inherited from parents.
- Autoimmune causes (Antiphospholipid antibodies). These antibodies complicate the embryo attachment onto the endometrium, and additionally turn on thrombosis through the placenta veins.
- Infectious cause. Toxoplasmosis and rubella. In women not vaccinated and with not previous infections (not immunized women).
- Uterus anatomical abnormalities. Some abnormalities in the uterine cavity might induce miscarriage. For example a septum, this should be removed.
- Immune cause o Natural Killer cells (NK / KIR ). Lymphocytes or defense cells activate an immune response against the embryo, avoiding its implantation into the uterus. Some combinations of the mother’s antibodies and embryonic antibodies are harmful since immune response is turned on.
Treatments against miscarriages
Fortunately, some treatments can avoid or almost minimize the risk of miscarriage.
Treatment will depend on the cause of abortion, so the first step is to get a diagnosis in order to apply the most suitable treatment.
- PGT o Pre implantation Genetic Testing for genetic causes. It consists of analyzing the embryos from an in vitro fertilization treatment in order to identify the embryos free from genetic disorders and transfer only the healthy ones into the uterus.
- ACC (Acetylsalicylic acid) + Heparin for autoimmune causes.
- Surgery to solve uterus anatomical defects.
Immune modulators (similar to those used in organ transplants to avoid the rejection) in order to avoid the own NK attack against the embryo.