Recurrent Pregnancy Loss

Implantation failure and pregnancy loss represent a spectrum of problems that share some causes.

Implantation failure can present as longstanding unexplained infertility, or repeated IVF implantation failures with chromosomally normal embryos.

Biochemical pregnancy is a type of early pregnancy loss that occurs when a woman has a positive pregnancy test, but the pregnancy hormone levels decline before a pregnancy is seen on ultrasound.

Clinical miscarriage refers to those losses that occur after a pregnancy is documented by ultrasound.

While all three categories share some causes, we individualize the approach to each patient, based on what type of problem she has experienced. In order for a viable pregnancy to occur, all of the following must be present:

1. Normal and viable blastocyst (early embryo)
2. Structurally normal uterus
3. Synchrony between the endometrium and embryo
4. Normal decidualization: changes in the endometrium that permit the embryo to invade into the uterus which are mediated by immunologic processes.
5. Placentation: the ability of the embryo vasculature to merge with maternal blood supply and create tiny blood vessels and form a placenta.

Our approach is to evaluate each category and try to understand why a viable pregnancy may not occur, despite conventional treatment.

Abnormal chromosomes in the embryo: It is important to remember that the majority of individual miscarriages are due to abnormal chromosomes in the embryo. Even with repeat miscarriages, abnormal embryos can be the cause. When it is found that a chromosomally normal (euploid) embryo is lost through miscarriage or repeat IVF implantations fail in spite of euploid embryos being present, evaluation of other causes of miscarriage becomes important.

Chromosomal translocation: A rarer cause of recurrent pregnancy loss is a chromosomal translocation in either parent. A translocation is when a piece of one chromosome breaks off at conception and sticks to another chromosome. While the person carrying such a rearrangement is healthy because they have all the necessary genetic material, the resulting sperm or eggs have a high chance of having abnormal amounts of DNA. This can result in recurrent miscarriages, and in some cases babies with genetic conditions like Down Syndrome. The incidence of a translocation in the general population is 1/10,000. For couples with three or more miscarriages, the incidence is estimated at 3-5%. So, when a couple has three or more clinical miscarriages, we recommend that both parents have a chromosome analysis (karyotype) to make sure neither one carries a translocation, or other rare conditions.

A normal embryo needs a normal uterus. This is an obvious statement. However, it is surprising how often this simple fact is ignored. We strongly recommend that all women undergoing IVF—especially those with repeat failures—and those with recurrent losses without IVF treatment, have a uterine evaluation. The oldest test available that still gives the most information is the hysterosalpingogram (HSG, or x-ray dye test). An HSG evaluates the uterus and also rules out an abnormality of the fallopian tubes called hydrosalpinx. We can also perform a sonohysterogram or hysteroscopy to evaluate the uterine cavity if we are not concerned with the fallopian tubes.

Abnormalities of the uterine cavity include:

• Uterine septums: A septum is a congenital abnormality in which a membrane divides the uterus into two cavities. Septum is associated with an increased risk of miscarriage and obstetric complications such as preterm birth and fetal malpresentation. A septum can be removed with a minimally invasive outpatient procedure called a hysteroscopy.
• Scar tissue: Uterine scarring can occur due to procedures like D&C, cesarean sections, uterine surgeries, severe infections, or trauma to the uterine lining, all of which can lead to the formation of scar tissue.
• Polyps or submucous fibroids: Polyps and submucous fibroids are benign tumors that grow in the uterine cavity and can cause implantation failure. All of these problems can be readily treated with a minor procedure called hysteroscopy.
• Hydrosalpinx: A hydrosalpinx is a dilated and blocked fallopian tube, usually caused by a prior pelvic infection. It has been shown in multiple studies that the presence of a hydrosalpinx reduces IVF success rates by 50%.

Each of these conditions can be treated surgically, in most cases using minimally invasive techniques like hysteroscopy.

Chronic endometritis is a persistent, low-grade inflammation of the uterine lining usually caused by a subtle bacterial presence. Unlike a typical infection that makes you feel ill, this condition often goes unnoticed because it lacks obvious symptoms, yet it creates a hostile environment for a developing embryo. By treating the inflammation with a targeted course of antibiotics, we can restore the health of the uterine lining and ensure it is receptive and welcoming for a future pregnancy.

Antiphospholipid antibody syndrome (APS) is an autoimmune condition where the body mistakenly produces proteins that increase the risk of blood clots. In the context of pregnancy, these antibodies can interfere with how the placenta attaches to the uterus or cause tiny clots that block the flow of nutrients to the growing baby. It is a frustrating hurdle, but once identified through blood testing, it is very manageable, typically requiring simple blood-thinning medications to help support a safe and healthy term.

Hormonal imbalances involving the thyroid, insulin, or prolactin levels can significantly disrupt the delicate environment needed to maintain a pregnancy. When the thyroid is underactive or blood sugar is poorly controlled, the body may struggle to support the metabolic demands of a developing fetus. Similarly, elevated prolactin can interfere with the progesterone production necessary to hold a pregnancy in place. Correcting these levels through personalized medication or lifestyle adjustments often clears the path for the body to function exactly as it was meant to.