The diagnosis of the etiology of recurrent miscarriage is a complex matter, with embryonic chromosomal abnormalities, being the more certain cause of spontaneous miscarriage. The remaining etiologies include endocrine factors such as hypothyroidism, insulin resistance, obesity, hyperprolactinemia, follicular dysplasia and luteal insufficiency; uterine morphological abnormalities, but the relationship with miscarriage is not always conclusive; autoimmunity and embolism, which are further reference diagnoses.
Diagnostic recipe for recurrent miscarriage
Spontaneous miscarriage is a heartbreaking topic, and the most common question couples ask when they visit the clinic is: “What is the cause of my miscarriage?” “Is the miscarriage due to the sperm or the egg?” “Our test results are normal, what’s the next step?” In the face of these unanswered questions, let me try to talk to you about miscarriage.
The etiology of miscarriage is complex and uncertain. In domestic and international guidelines and consensus, the etiology of miscarriage is mostly summarized as follows
①genetic factors
②Uterine structure factors
③Endocrine factors
④Immune factors
⑤Tendency to thrombosis
⑥Infection factors, etc.
However, in fact, except for chromosomal abnormalities of the couple or fetus, other etiologies are often difficult to determine, and the evidence of clinical tests is not very sufficient, so our ability to judge the etiology is limited. Therefore, based on the available literature, and our knowledge of spontaneous abortion, and our experience in dealing with it, we provide the following consultation views.
1. Chromosome examination of both spouses is the first step
If one of the couples is a reciprocal chromosome translocation or a Roche translocation carrier, the risk of chromosomal abnormalities in the fetus is higher, which may lead to infertility, recurrent spontaneous abortion, and the birth of a deformed child with low IQ.
In some couples, chromosomal “abnormalities” are actually polymorphic variants and are not pathological. The common ones are inter-arm inversion of chromosome 9, large Y chromosome, and increased chromosome followers of D/G group.
2.Why should we do the examination of chorionic villi chromosome for miscarriage
Some doctors may think that the occurrence of aneuploidy in spontaneous miscarriage is a random event, and since miscarriage has already occurred, checking the chorionic villi chromosome cannot change the outcome of this miscarriage, so why bother.
The incidence of chorionic villus aneuploidy in spontaneous miscarriage is about 50%, and with the results of this test, at least half of the causes of this miscarriage can be answered. Without evidence of a chorionic chromosome test, doctors are often unable to answer questions about the cause of the miscarriage.
If the chorionic chromosome is abnormal and occurs consecutively, it suggests an increased risk of miscarriage due to chromosomal abnormalities in the fetus in the next pregnancy, without much other cause testing, and if necessary, third generation in vitro fertilization (PGS) can be recommended; if the chorionic chromosome test is of normal karyotype, it means that the cause of this miscarriage is not chromosomally related, and the examination of other causes needs to be considered for attention.
3. Endocrine causes are also important
Endocrine causes related to miscarriage include: hypothyroidism, insulin resistance, obesity, hyperprolactinemia, follicular dysplasia and luteal insufficiency. Therefore, screening for the etiology of recurrent miscarriage includes these indicators. The doctor will advise the patient to lose weight, establish a good lifestyle, correct thyroid function and prolactin levels, and promote ovulation and luteal support if necessary.
4. Examination of the uterine cavity and endometrial morphology is relatively easy
Ultrasound examination of the uterine cavity and endometrial morphology can be performed at the same time as the ovulation monitoring cycle. It is relatively easy to see uterine malformations, endometrial adhesions, intrauterine polyps, fibroids, and other problems.
5. Autoimmune and thrombotic tendencies are further tests
If none of the above causes are found to be abnormal, only then will autoimmune and thrombotic indicators be further examined, including a series of autoimmune antibodies, coagulation function, and other items of thrombophilia. Other than confirming a diagnosis of antiphospholipid syndrome, these types of tests are not necessarily conclusive diagnostic evidence and can be referred to. The screening for blocking antibodies is highly controversial and the test is imprecise and can only be used as a reference for information.
Spontaneous abortion is a complex problem, and many presumed etiologies do not necessarily have diagnostic evidence. In the absence of conclusive evidence, the etiology can only be broadly presumed, examined and managed. Some patients can only try to conceive while waiting for a good time to conceive, or while waiting for evidence of etiological diagnosis to appear.