What Are Pregnancy Losses?
Pregnancy loss is defined as the termination of pregnancy before the 20th gestational week. Approximately 10–15% of clinically recognized pregnancies end in miscarriage.
In 50–75% of pregnancy losses, genetic factors are responsible — most commonly chromosomal number or structural abnormalities in the embryo.
Women who experience three or more consecutive pregnancy losses represent about 1% of women of reproductive age, and this condition is classified as recurrent pregnancy loss (RPL).
When Should Pregnancy Loss Be Investigated?
In some cases, it is crucial to perform a detailed evaluation early to determine the underlying cause of pregnancy loss. If fetal cardiac activity had previously been observed but pregnancy still ended in loss, this may indicate an underlying pathological condition.
If a karyotype analysis (chromosomal study) from a previous miscarriage revealed normal results, and the maternal age is over 35, a more comprehensive investigation is recommended. Similarly, if the mother has a history of infertility, or if chromosomal abnormalities have been detected in either parent, advanced diagnostic testing is warranted.
Today, the occurrence of two consecutive miscarriages is considered sufficient reason to initiate diagnostic evaluation. Early investigation helps plan future pregnancies and allows preventive measures to be implemented effectively.
What Are the Causes?
Pregnancy losses may result from a variety of factors. Among these, anatomical abnormalities of the uterus are the most frequent causes. Congenital structural defects may interfere with implantation or fetal development, increasing the likelihood of miscarriage.
Common congenital uterine anomalies include:
- Uterine septum (a dividing wall within the uterine cavity)
- Unicornuate uterus (a uterus developed from one side only)
- Uterus didelphys (double uterus)
- Bicornuate uterus (heart-shaped uterus)
In addition, acquired uterine conditions such as fibroids (myomas) and intrauterine adhesions (Asherman’s syndrome) can also contribute to pregnancy loss.
Another significant category involves immunological factors. Autoimmune diseases such as systemic lupus erythematosus (SLE) and antiphospholipid antibody syndrome (APS) can trigger excessive blood clotting, disrupt placental circulation, and lead to early pregnancy loss.
Similarly, inherited thrombophilia disorders (conditions that increase blood clotting tendency) can impair blood flow to the placenta, restrict embryonic nourishment, and cause miscarriage.
Which Tests Are Used for Diagnosis?
Determining the cause of pregnancy loss often requires advanced diagnostic testing. Blood samples are taken from both parents for karyotype analysis to assess chromosomal structure and abnormalities.
To evaluate potential anatomical uterine abnormalities, the following diagnostic methods may be employed:
- 4D ultrasonography
- Hysterosalpingography (HSG) – contrast-enhanced imaging of the uterus and fallopian tubes
- Hysteroscopy – direct visualization of the uterine cavity with a camera
- Laparoscopy – minimally invasive examination of pelvic structures
In addition, blood samples from the mother are tested for thrombophilia (coagulation disorders) and immune system abnormalities using specialized thrombophilia and autoimmune panels.
If pregnancy occurs again after recurrent losses, invasive prenatal diagnostic procedures can be performed to examine the fetus’s chromosomes, such as:
- Amniocentesis (sampling of amniotic fluid)
- Chorionic Villus Sampling (CVS)
- Cordocentesis (sampling of fetal blood from the umbilical cord)
These procedures provide definitive chromosomal information about the fetus and are essential in guiding clinical management and future pregnancy planning.
