Dr. Catherine E Gordon, MD

After an egg retrieval for a fresh cycle, or when contemplating a frozen embryo transfer, women often wonder how many embryos should be placed into the uterus. Usually, single embryo transfer (SET) is promoted, especially if an embryo is genetically tested (undergoes pre-implantation genetic testing, PGT). However, there are cases where a patient may want to transfer two or more embryos. Examining the pros and cons of multiple embryo transfer can help women make an informed decision.

‍

Sexually transmitted infections (STIs) can potentially damage the reproductive organs and lead to infertility. It is crucial for sexually active individuals, regardless of age, gender, or sexual orientation to undergo STI testing regularly in order to proactively take responsibility for their sexual health. Early diagnosis and management of STIs are essential for avoiding long-term harm to reproductive organs and for maintaining fertility. This article covers what STIs are, how they may impact fertility, and options for their prevention and treatment.

An embryo transfer is usually the final step in the process of in vitro fertilization (IVF), where the embryo is transferred to the patient’s uterus. The embryos used in this procedure may either be fresh or thawed (after being frozen).

During IVF, mature eggs are fertilized, either by conventional IVF (insemination) or intracytoplasmic sperm injection (ICSI), after which the resulting embryos are grown in an incubator in the embryology laboratory. An embryo transfer is the procedure whereby one or more of the embryos that has been grown in the lab setting is then transferred from culture media into the patient’s uterus, in the hopes of initiating a pregnancy.  

Fresh embryo transfers are those in which the embryo was fertilized after the ovarian hyperstimulation and egg retrieval process, then transferred in the same cycle. As such, the embryo has never been frozen.ⁱ

Alternatively, embryos can be frozen and preserved by a process called cryopreservation, and then stored to be transferred in a subsequent cycle. This is known as a frozen embryo transfer (FET) and requires the cryopreserved embryo to be thawed before transferring into the uterus.ⁱⁱ

There has been a significant increase in the number of frozen embryo transfer cycles being performed in the last decade due to better cryopreservation techniques, improvement in embryo culture media, providers choosing the “freeze-all” strategy to avoid ovarian hyperstimulation syndrome, more patients undergoing embryo banking for fertility preservation or family planning, and advancements in preimplantation genetic testing.ⁱⁱⁱ

After an egg retrieval for a fresh cycle, or when contemplating a frozen embryo transfer, women often wonder how many embryos should be placed into the uterus. Usually, single embryo transfer (SET) is promoted, especially if an embryo is genetically tested (undergoes pre-implantation genetic testing, PGT). However, there are cases where a patient may want to transfer two or more embryos. Examining the pros and cons of multiple embryo transfer can help women make an informed decision.

Pregnancy loss can be devastating under any circumstances, but repeated losses can be particularly difficult to deal with. Recurrent pregnancy loss is defined as having two or more miscarriages. Overall, the risk of pregnancy loss is approximately 25 percent, meaning 1 in 4 recognized pregnancies end in loss. The risk of having two or three pregnancy losses in a row is approximately 2.25 percent and 1 percent respectively. After three consecutive losses, the risk of another pregnancy loss rises to around 40 percent.ⁱ  

In order to understand recurrent pregnancy loss (RPL), it is important to know the potential causes of RPL and what tests and treatments are available to help women experiencing the devastating impact of recurrent miscarriage.

Mitochondrial replacement therapy (MRT) is a highly controversial type of therapy used to either prevent genetic disease or support in vitro fertilization (IVF) success when advanced maternal age may be an issue. The therapy is not currently practiced or legal in many countries, including in the United States or Canada, as the practice is considered a very experimental form of genetic modification. Mitochondrial replacement therapy often comes up during online research related to the concept of a “three-person baby.” Several terms are misused in attempting to define mitochondrial replacement, and the procedure itself is often misunderstood. This leads to questions about the idea of a three-person baby, which is technically not an accurate description of mitochondrial replacement therapy.

Embryo implantation is a complex process and a significant step towards achieving a viable pregnancy. Implantation requires good quality embryos (both genetically and structurally normal), a receptive endometrium, and complex communication between the embryo and the uterine lining.ⁱ The term “implantation failure” describes the lack of a positive pregnancy test (increased human chorionic gonadotropin (hCG) levels) or the lack of an intrauterine pregnancy seen on ultrasound following in vitro fertilization (IVF) and embryo transfer.ⁱⁱ Recurrent implantation failure (RIF) is sometimes called repeated implantation failure, and the terms can be used interchangeably.

For women who are thinking about in vitro fertilization (IVF), there is a great deal of information to absorb at once, and much of it can be confusing. In particular, the discussion of an egg (oocyte) vs. follicle involves a significant dive into the mechanisms of IVF. While women may know they are born with all the eggs they will ever have, they may not necessarily understand how their eggs differ from follicles and how these terms are used during IVF. Understanding what each term entails can make the process easier to navigate.

A miscarriage is the loss of a clinically confirmed pregnancy. For women hoping to conceive, it is important to have accurate information regarding pregnancy loss including prevalence, common causes, warning signs, and management options. An understanding of what to expect after miscarriage and what physical and emotional factors should be considered before trying to conceive again can also be highly beneficial.

Asherman’s syndrome is a rare condition defined by the formation of scar tissue in the uterine cavity. It does not have a genetic predisposition and can affect any woman, with a potential impact on fertility. Most cases develop in women who have undergone uterine surgeries. If a woman has received an Asherman’s syndrome diagnosis and is concerned about its impact on her fertility, it is beneficial to understand the symptoms, causes, and range of potential reproductive outcomes.

Reproductive immunology is a subspecialty of reproductive medicine that aims to help individuals or couples using assisted reproductive technology (ART) achieve successful pregnancy outcomes. The components of understanding reproductive immunology include how the immune system affects human reproduction, what a reproductive immunologist does, and why a woman may choose to consult with a reproductive immunologist.

For some potential parents, the innate immune system—including immune cells called natural killer cells (NK cells)— may play a role in whether or not a pregnancy can be achieved. Knowing what natural killer cells are, the tests for these cells, and possible treatments for high natural killer cell levels can help intended parents better understand their fertility options.

Difficulty with conception can at times be traced to issues within the structure of the reproductive tract, such as the shape of the uterus or blocked fallopian tubes. If a doctor suspects that to be the case, a hysterosalpingogram may be recommended. The hysterosalpingogram is a relatively common diagnostic procedure in reproductive medicine, which gives doctors the ability to see how the uterus and fallopian tubes are shaped.