If you are undergoing in vitro fertilization (IVF), you have likely undergone many weeks, months, or years of procedures, medications, and sustained hope. To experience a miscarriage after all of this can be heartbreaking, and you may find yourself looking for an explanation. Below, we will detail how to recognize a miscarriage, causes and risks of miscarriage, and when to talk to your doctor, as well as some positive news about your chance of success with your next embryo transfer.

Six Second Snapshot

• Miscarriage is common, whether you conceive without assistance or through IVF.

• Diagnoses that may increase your chance of miscarriage include endometritis, uterine factor, cervical factor, autoimmune system disorders, genetic cause (such as balanced translocation), hormonal issue (such as luteal phase defect), or recurrent miscarriage.

• A 2002 study published in Fertility and Sterility showed that patients who experienced an early pregnancy loss had a greater chance of success during their next IVF cycle than patients who did not get a positive pregnancy test (1).

What is a miscarriage and what are the symptoms?

A miscarriage occurs when a pregnancy naturally and unexpectedly ends before 20 weeks gestation, though most occur in the first trimester (first 12 weeks of pregnancy). Other ways you may hear it described are “early pregnancy loss,” “chemical pregnancy,” or “spontaneous abortion.”

Common symptoms of miscarriage include spotting, vaginal bleeding, cramping (similar to menstrual cramps), lower back pain, pelvic pain, passing tissue, white/pink mucus coming from the vagina, and/or a decrease in symptoms you experienced during pregnancy, such as a lessening of nausea or breast tenderness.

It’s important to contact your fertility care team if you suspect a miscarriage. They will be able to help confirm a miscarriage, ensure that the fetal tissue has completely left your uterus, and/or diagnose an “incomplete abortion,” in which some of the tissue is still in your uterus. If there is still tissue in your uterus, you may need to undergo a uterine curettage (D&C), in which the tissue is manually removed from your uterus, or they may order the oral medications mifepristone and misoprostol, which will help your body to remove the tissue on its own. Your clinician may also be able to determine the cause of your miscarriage, which could help you decide how you want to proceed with your fertility journey.

You may need to contact your fertility clinic if you are experiencing very heavy bleeding (more than one or two pads an hour), increased or persistent bleeding, have developed a fever, are passing large clots, or have severe abdominal pain.

Is there an increased risk of miscarriage with IVF?

Miscarriage is common, whether you conceive without assistance or through IVF. About 10-20% of unassisted, confirmed pregnancies end with miscarriage, but some research puts the rate of miscarriage at about 1 in 4 unassisted pregnancies, since many miscarriages occur before a person even knows they are pregnant.

For pregnancies that result from assisted reproductive technologies (ART), a review of 62,228 pregnancies resulting from ART found that 14.7% of them ended in a miscarriage (spontaneous abortion) (2). This puts the rate of miscarriage at about the same as an unassisted pregnancy.

Below, we will discuss some of the conditions that may increase your chance of miscarriage.

What are the causes of miscarriage, especially during IVF?

The most common cause of miscarriage, whether conception occurred without assistance or through IVF, is a chromosomal abnormality in the fetus. One way to reduce your chance of miscarriage is to conduct preimplantation genetic testing (PGT) on your embryos before embryo transfer (3). This is especially useful if you or your partner are of advanced maternal age, since PGT can help improve first embryo transfer success rates (4). However, PGT may not be appropriate for all patients, such as poor ovarian responders (5), so it’s important to talk to your clinician about whether it’s the right choice for you.

Some medical conditions/risk factors that may increase your chance of miscarriage include:

• Endometritis - Not to be mistaken with endometriosis (in which endometrial tissue migrates outside of the uterus), this infection causes inflammation in the lining of your uterus and can cause implantation failure and miscarriage. Antibiotic treatment for endometritis can significantly improve your chance of a successful pregnancy (6).

• Uterine Factor - Issues with the uterus – such as a too-thin lining, uterine fibroids and/or uterine polyps, or an abnormally shaped uterus – can contribute to miscarriage.

• Cervical Factor - Sometimes referred to as an “incompetent cervix” or “cervical insufficiency,” a cervix that dilates, weakens, or shortens before the pregnancy is at term can cause a miscarriage.

• Autoimmune System Disorder - Patients with autoimmune disorders such as lupus, inflammatory bowel disease (IBD), rheumatoid arthritis, and more, can experience miscarriage if the immune system identifies the fetus as a foreign object.

• Genetic Cause - If you or your partner have a condition such as balanced translocation (in which sections of two chromosomes have switched places), you are at higher risk of miscarriage.

• Hormonal Issue - Conditions such as luteal phase defect (low progesterone levels) can result in miscarriage.

• Recurrent Miscarriage - This is diagnosed if you have experienced three or more miscarriages. Many health problems can contribute to recurrent miscarriage, such as thrombophilia (blood clotting disorder), diabetes, thyroid conditions, high levels of stress, and more.

Many of these can be treated or controlled before starting IVF, which can decrease your risk of miscarriage.

Does a miscarriage mean I have a decreased chance of success with my next embryo transfer?

Actually, research shows that the opposite may be true. A 2002 study published in Fertility and Sterility showed that patients who experienced an early pregnancy loss had a greater chance of success during their next IVF cycle than patients who did not get a positive pregnancy test (1).

Your clinician may also be able to use information from your miscarriage to help inform your care going forward. This may mean ordering tests or procedures to decrease your risk of miscarriage, suggesting PGT testing, or changing from a fresh to a frozen embryo transfer (or vice versa).

As a note: in researching your chance of success with IVF, you may see the terms “pregnancy rate” or “live birth rate.” These are not interchangeable, because a successful implantation and clinical pregnancy may still result in miscarriage. The pregnancy rate is the percentage of patients who were able to get pregnant, and the live birth rate is the percentage of patients who had a live birth. Both are significant in understanding success rates during IVF.

If you are experiencing or have experienced a miscarriage, it’s important to get care in all of the ways: from your fertility care team, from your loved ones, and from yourself. It’s okay to do whatever you need, whether it’s taking time to grieve, connecting with other people who have experienced miscarriage, meeting with your doctor to understand your next steps, or getting support from your partner. We hope this information helps you understand miscarriage, prepares you for IVF, and helps to inform your next steps.