The exact reason cannot be known, of course, but the most common reason for chemical pregnancies is a genetic abnormality in the embryo.
As a woman ages, more and more of her eggs become weakened/debilitated leading to abnormal embryo formation. Therefore the miscarriage rate increases. If the chemical pregnancy occurs after an in vitro fertilization cycle (IVF) or an intra-uterine insemination cycle (IUI), it can be a good sign. Keep in mind that assisted reproductive technologies can only give you the opportunity to get pregnant. Whether or not implantation and pregnancy occur are up to the body’s and the embryo’s natural processes. We do not have the technology to make that happen. It has to happen on its own. So the fact that those processes occurred is always a very good sign. It is for this reason that we draw our bHCG’s earlier than most clinics in order to see if the patient has a chemical pregnancy. If the patient has had a chemical pregnancy there is a high likelihood that she will achieve pregnancy eventually.
IVF & Chemical Pregnancy
After IVF, the patient undergoes a blood test for pregnancy within nine days. Some clinics want to be absolutely sure so they wait for 14 days but the problem with that protocol is that an early chemical pregnancy will be missed, and for our clinicians, it is important to know if a chemical pregnancy occurred or not. This event is important to know because it verifies that the patient can become pregnant with IVF and that the last steps actually occurred. The majority of chemical pregnancies occur because the embryo is genetically abnormal. It would be good to know that those last steps, those steps that are beyond our technology, can occur on their own.
Once the woman gets a positive bHCG, that means that implantation occurred. To be more specific, it means that after the embryo was transferred into the endometrial cavity (the limit of what IVF can do), the embryo progressed in its development, hatched out of its shell, attached to the endometrial lining and the lining grew and enclosed the embryo. These last steps are all natural steps that we do not have the technology to make happen. They have to happen on their own. With that knowledge the patient can be reassured that this treatment can work, that her body can do what it needs to do, and it is just a matter of getting a perfect embryo into her womb for her to be successful. The take away message from this is the knowledge that the patient can achieve a pregnancy with IVF. The ensuing problem, of miscarriage, is a pregnancy issue. Whether or not the embryo progresses to developing a successful pregnancy and ultimately a normal and healthy baby is based on the pregnancy alone.
Miscarriage is a more common occurrence than people think. We know that up to 50% of pregnancies can end in a miscarriage, many of which are chemical pregnancies. In most cases of early miscarriage, the reason is because of an abnormal embryo, meaning the embryo had some sort of genetic abnormality. In most of these cases, it is a spontaneous abnormality that occurred at the time of embryo division and not something that the woman carries. To be on the safe side, with multiple IVF failures, the husband and wife may want to undergo genetic testing before proceeding any further.
Failure Due To Male Factor
Some couples may have male factor influencing the outcome of the pregnancy. Not only can this occur with couples >35 yrs. of age, but it is seen in young couples where the woman is under 35 years old and whose husband tests with poor morphology in the semen analysis. In this case, definitely the genetic weakness could be from the sperm. Dr. Ramirez does not recommend the sperm DNA fragmentation test because it only gives the indication for the batch of sperm that it tests and not the sperm as a whole.
The treatment recommendation is to use ICSI with IVF. If the cycle fails then other than ICSI the couple has the choice of either using donor sperm or using a supplement for three months before doing IVF again. The supplements that the husband can try, which might help with sperm quality, are either Proxeed or Fertility Blend (vitamins) and CoQ10 600 mg per day. He will have to wait three months because since sperm are on a 90 day cycle, the sperm made today won’t be expressed for 90 days. See our page on “Male Factor Infertility” for more information.