It’s estimated that one in five pregnancies will end in miscarriage and, despite the prevalence of pregnancy loss, it’s often difficult to answer the question of why. The most common reason is due to chromosomal aneuploidy (when the developing fetus has the incorrect number of chromosomes), which account for about 50 percent of miscarriages. All cells in the human body have 23 pairs of chromosomes—one set that comes from the egg and one set that comes from the sperm—for a total of 46 chromosomes. (The only exception are the sex cells which each have one set.) If an embryo doesn’t have 46 chromosomes they are referred to as aneuploid. These embryos will either stop developing prior to implantation or will reach implantation but then miscarry at some point in development.
Miscarriage Tissue Testing, also known as Products of Conception (POC) Testing can determine whether the cause of miscarriage was chromosomal aneuploidy and help provide answers to grieving patients and direct physicians to strategies for reproductive success.
What is Miscarriage Tissue Testing or POC Testing?
POC Testing is an advanced genetic screening of miscarried fetal tissue that analyzes DNA to determine if the miscarriage was caused by chromosomal aneuploidy. The test does this by comparing the chromosomes from miscarried tissue to a normal reference human genome.
How do you get a POC Test?
Miscarriage, and the passing of miscarriage tissue, can happen in several ways: you might begin to spontaneously bleed at home, you might learn at an appointment that you have suffered a pregnancy loss and your doctor might give you the option of inducing a miscarriage with medication, or a doctor might recommend a surgical remedy called dilation and curettage (D+C). Regardless of how miscarriage happens, if you want a POC Test, you can request it. Your clinic may keep Igenomix POC Test kits in stock, or you can request a kit directly to your home from Igenomix. The key is to obtain the tissue and place in the kit as directed, whether it’s collected at home or by your doctor from a D+C procedure.
How to use the Igenomix POC Test kit
Inside the test kit, you will find a specimen cup that contains saline solution, used to collect miscarriage tissue. You will also find a blood collection tube and a cheek swab to collect a DNA sample from the pregnant person—use the cheek swab to collect DNA at home, while the blood collection tube will be used by a doctor to collect DNA if you are undergoing a D+C procedure at a clinic. It’s important that the DNA of the pregnant patient be collected to cross reference to the pregnancy tissue itself. Once you (or your clinic) send the kit back to Igenomix for testing, it will take approximately seven to 10 days to get the results. While you are waiting, reach out for help. You are not alone and there are resources available to help with loss and grief.
How to save miscarriage tissue for testing
Miscarriage tissue can include blood, blood clots, the placenta, the fetus and the amniotic sac. If undergoing D+C, your doctor will collect the tissue. If you are managing a miscarriage at home, either with or without the aid of medication, you will need to collect the tissue yourself. You can collect tissue from a pad or from the toilet—the key is to collect as much tissue as possible to receive a more accurate result. This may mean that you collect tissue over several days, keeping the specimen cup and kit in the refrigerator and adding to it until the miscarriage is complete. (Igenomix is available to assist with this process. Please reach out to firstname.lastname@example.org (USA) or email@example.com (Canada).)
What are the possible results from POC testing?
Normal/Euploid of fetal origin: If the tested fetal tissue had 46 chromosomes, then the result is considered normal. This means that it was not chromosomal aneuploidy that caused miscarriage. As a next step, you doctor will begin to investigate other possible reasons for miscarriage which might include evaluating your immune system, the structure of your uterus and your hormone levels.
Abnormal: If the tested tissue does not have 46 chromosomes, then the result will be abnormal, indicating that miscarriage likely occurred because of chromosomal abnormality. You’ll receive the exact findings, indicating the specific abnormality detected. Some common results include:
- Trisomy: The most common abnormality found in miscarriage (70 percent of abnormal POC results) is when there are three copies of chromosomes instead of two
- Polyploidy: More than two complete sets of all chromosomes
- Monosomy: One copy of a chromosome instead of two copies
- Deletions and Duplications: Small missing or extra pieces of chromosomes
- Mosaicism: A mix of abnormal and normal test results.
- Maternal Cell Contamination (MCC): MCC (also reported as Normal/Euploid Female of Maternal Origin in the results) happens when the tissue cannot be distinguished from the carrier (this is why the pregnancy carrier also provides a DNA sample when submitting the test). Essentially this represents no real insight into the cause of the miscarriage. MCC prevents evaluation of miscarried tissue 20 percent of the time and the likelihood of receiving this inconclusive result is higher with at-home collection, or with lower gestational age (if the tissue collected is under eight weeks gestation, this percentage rises to 25).
When is POC Testing recommended?
POC Testing can be considered by anyone who wants to learn the reason for a pregnancy loss. If you are seeing a physician specifically for Recurrent Pregnancy Loss (RPL), the test might be more strongly recommended by your physician. There is no defined gestational age at which POC Testing can be performed, however, if a loss occurs at five weeks or less, it may be very difficult to collect fetal tissue as it’s less developed.
What do I do after receiving a POC Test result?
If this is your first pregnancy loss, your doctor will not likely make any specific recommendations. But if this is not your first loss, your doctor might recommend a karyotype (a deeper look into the chromosomes of the couple or egg and sperm providers) to check if there is a translocation (an unusual arrangement of chromosomes—people who carry translocations are far more likely to suffer miscarriages).
Importantly, regardless of your POC Test result, you can book a genetic counseling session with an Igenomix genetic counselor to review your report. Please email firstname.lastname@example.org to book a session.
POC Testing can identify the cause of miscarriage and decrease the need for further investigation and testing. Alternatively, it can rule out chromosomal aneuploidy as the cause of miscarriage and help quickly direct investigation into other possible causes. Understanding why a miscarriage happened can help bring closure to someone suffering a pregnancy loss and help doctors determine next steps.
Igenomix is a fertility company working with doctors and clinics to develop techniques and products related to fertility and reproductive genetics.