Dr. Catherine E Gordon, MD

Embryo implantation is a complex process and a significant step toward achieving a viable pregnancy. Implantation is aided by 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 — and therefore lack of increased human chorionic gonadotropin (hCG) levels, or the lack of an intrauterine pregnancy seen on ultrasound following in vitro fertilization embryo transfer.ⁱⁱ When implantation failure happens multiple times, it is known as recurrent implantation failure (RIF) or repeated implantation failure. The terms can be used interchangeably.

Pregnancy loss can be devastating under any circumstances, but recurrent pregnancy loss (RPL) — defined as two or more miscarriages — can be particularly difficult. Overall, the risk of pregnancy loss is approximately 25 percent, meaning one in four clinically recognized pregnancies end in loss. The risk of two or three pregnancy losses in a row is about 2.25 percent and 1 percent, respectively. After three consecutive pregnancy losses, the risk of another pregnancy loss rises to around 40 percent.ⁱ

To understand recurrent pregnancy loss, it is important to know the potential causes of recurrent pregnancy loss and what tests and treatments are available to help individuals and couples experiencing the devastating impact of recurrent miscarriage.

Reproductive immunology is an area of interest in reproductive medicine that aims to help individuals or couples achieve successful pregnancy outcomes when trying to conceive. Understanding reproductive immunology includes learning how the immune system affects human reproduction, what a reproductive immunologist does, and why someone may choose to consult with the reproductive immunologist in the first place.

For some potential parents, the innate immune system — including immune cells called natural killer (NK) cells — may play a role in whether a pregnancy can be achieved. Knowing what natural killer cells are, what tests for these cells exist, and possible treatment options for high natural killer cell levels can help intended parents better understand their fertility options.

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

Mitochondrial replacement therapy (MRT) is a highly controversial procedure 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 it is considered a very experimental form of genetic modification.

Mitochondrial replacement therapy often comes up when the term “three-person baby” is searched online, even though the two concepts are not synonymous. Several terms are frequently misused in attempting to define mitochondrial replacement, and the procedure itself is often misunderstood.

At times, difficulty with conception can be traced to issues within the structure of the reproductive tract, such as the shape of the uterus or blockages in the fallopian tubes. If a physician suspects structural concerns, they may recommend a hysterosalpingogram. The hysterosalpingogram is a relatively common diagnostic procedure in reproductive medicine that gives doctors the ability to see how the uterus and fallopian tubes are shaped.

After an egg retrieval for a fresh cycle, or when contemplating a frozen embryo transfer, patients 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, meaning it undergoes preimplantation 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 transfers can help patients make an informed decision.

An embryo transfer is usually the final step in the process of in vitro fertilization (IVF), in which 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). Next, the resulting embryos are grown in an incubator in the embryology laboratory. Finally, an embryo transfer is the procedure whereby one or more of the embryos that have been grown in the lab are then transferred into the patient’s uterus in the hopes of initiating a pregnancy.

Fresh embryo transfers involve transfer to the uterus several days after egg retrieval within the same IVF cycle. The embryo is never frozen.ⁱ Alternatively, embryos can be frozen and preserved (known as cryopreservation), then stored to be transferred in a subsequent cycle. This process is known as a frozen embryo transfer (FET) and requires the cryopreserved embryo to be thawed before transfer into the uterus.ⁱⁱ

For people 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 eggs (also called oocytes) versus follicles involves a significant dive into the mechanisms of egg development and maturation. While females 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 means can make the process easier to navigate.

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

Asherman’s syndrome is a rare condition in which scar tissue is present in the uterine cavity. It is not a genetic condition; therefore, it can affect any female. In most cases, it develops in individuals who have undergone uterine surgeries. If someone has received an Asherman’s syndrome diagnosis and is concerned about its impact on their fertility, it is beneficial to understand the symptoms, causes, and range of potential reproductive outcomes.