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TWW, IVF, IDK: The Ultimate Guide To Fertility Acronyms

August 24th, 2022 | 12 min. read

TWW, IVF, IDK: The Ultimate Guide To Fertility Acronyms
Sierra Dehmler

Sierra Dehmler

Sierra Dehmler is Illume Fertility’s Content Marketing Manager - and also a fertility patient herself. Combining empathy gained on her personal journey with her professional experience in marketing and content creation, she aims to empower and support other fertility patients by demystifying the fertility treatment process.

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When you enter the world of infertility, you're forced to learn an entirely new language in order to understand your results, advocate for yourself, and communicate with your team. But getting all this new terminology under your belt can be confusing! Let's explore the most common fertility acronyms and terms so you can feel more empowered on your journey.

In this article:


The Language of Infertility 

Trying to understand fertility lingo can feel a bit like stepping into a foreign land. And when you're already overwhelmed about your next steps towards becoming a parent or protecting your future fertility, adding a whole new dictionary of terms, abbreviations, and acronyms to your brain can be an added stressor.

That's why we're here to help you crack the code to the language of infertility! Each section below dives into a specific phase of the fertility or family-building process to define the most commonly used terms and help you understand what lies ahead.

Why is knowing these terms helpful?

Becoming "fluent" in fertility speak helps you communicate more easily with your Care Team, advocate for yourself, and feel more confident during each step of the process. Remember: Your team will always be happy to explain these terms when needed if you forget what they mean, so don't be afraid to ask for clarification.

Preconception Terms

Trying to Conceive (TTC)

A term commonly used by the fertility community at large (both by those pursuing fertility treatment and those attempting pregnancy on their own) to describe focused efforts to conceive a baby. 

Semen Analysis (SA)

Examination of male ejaculate under a microscope to determine the number of sperm, their ability to move forward (motility) and their shape (morphology). Semen analysis is an essential part of fertility testing, particularly in couples experiencing infertility. Sperm count, motility and morphology all provide important information about how the sperm will perform in treatment cycles.

Basal Body Temperature (BBT)

This is your body's temperature at rest which can be taken each morning before getting out of bed. BBT is measured orally each morning and recorded on a calendar chart. These charts can help identify the time of ovulation in people with regular cycles. 

Ovulation Predictor Kit (OPK)

An OPK is a home test that checks your urine to predict when you're most likely to be fertile. When your body is preparing to ovulate (release an egg), it produces more luteinizing hormone (LH) which is what OPKs detect.

Luteinizing Hormone (LH)

A hormone made by the pituitary gland that plays an important role in sexual development and functioning. In women, LH helps control the menstrual cycle and trigger the release of an egg from the ovary. In men, LH causes the testicles to make testosterone, which is important for producing sperm. 

Birth Control Pill (BCP)

A daily medication containing hormones that prevent pregnancy. Also used during fertility treatment cycles.


A nurse explains why we use BCPs:


Fertility Testing Terms

Anti-Mullerian Hormone (AMH)

A hormone that corresponds to a person’s egg count and can help predict your current egg reserves. 

Follicle Stimulating Hormone (FSH)

A hormone produced by the pituitary gland that plays an important role in sexual development and functioning. In women, FSH helps control the menstrual cycle and stimulates the growth of eggs in the ovaries.

Thyroid Stimulating Hormone (TSH)

A hormone that stimulates the production of two main hormones (T4 and T3) and promotes healthy endocrine system function. An optimal TSH level is important for fertility, as these hormones affect ovulation.

Estradiol (E2)

One of the four types of estrogen produced mainly by the ovaries. The adrenal glands, placenta, testes, and some tissues also produce smaller amounts of this hormone. Often measured during fertility testing and treatment.

Hysterosalpingogram (HSG)

An x-ray procedure that detects whether the fallopian tubes are patent (open) or not, in order to determine if the tubes are blocking sperm from reaching ovulated eggs through the fallopian tubes. Special x-ray dye is gently injected through the uterus, then x-ray images are taken to see where the dye travels.

Saline Infusion Sonohysterogram (SIS or SHG)

Saline infusion sonohysterography (SIS or SHG) is a procedure to evaluate the state of the uterus and shape of the uterine cavity, and detect any abnormalities. Using ultrasound and sterile saline fluid, the uterus and uterine lining are closely examined to ensure the environment is healthy and optimal for a future pregnancy.

Endometrial Receptivity Analysis (ERA)

A special test performed during some IVF cycles to help determine whether the endometrium is receiving an embryo at the right time in an attempt to maximize chances of a successful pregnancy and live birth.

Genetic & Embryo Testing Terms

Preimplantation Genetic Testing (PGT)

A technique for identifying genetic or chromosomal information about embryos before transferring them into the uterus to achieve a pregnancy. There are three different types of PGT (see below). Learn more about PGT here.

Note: PGT is different from genetic carrier testing, which is performed on the intended parents to screen for genetically-inherited disorders or chromosomal abnormalities.

Preimplantation Genetic Testing for Aneuploidies (PGT-A)

PGT-A identifies aneuploidy, the term used to describe any embryo with either too many or too few chromosomes (or large extra or missing pieces of chromosomes). One form of aneuploidy causes Down Syndrome, and other chromosomal changes may cause up to 60% of miscarriages or prevent pregnancy altogether.

Preimplantation Genetic Testing for Monogenic/Single-Gene Disorders (PGT-M)

PGT-M tests for monogenic (single gene) disorders, such as Cystic Fibrosis, Huntington’s disease, Sickle Cell Anemia, muscular dystrophy, and hemophilia – detection that is especially important for people who know their families carry the defective gene.

Preimplantation Genetic Testing for Chromosomal Structural Rearrangements (PGT-SR)

PGT-SR looks for structural rearrangements when a parent is known to carry a chromosome change such as a translocation or inversion. These can cause extra or missing chromosomal material in embryos.


Explore the world of PGT:

A Genetic Counselor Explains PGT


Fertility Treatment Terms

Assisted Reproductive Technology (ART)

ART includes all clinical and laboratory treatments in which either eggs or embryos are handled with the intent to result in a pregnancy (for example, IUI and IVF).

Intracytoplasmic Sperm Injection (ICSI)

Placement of a single sperm into a single oocyte (egg) by penetrating the outer coating of the egg. This technique is used in cases with low sperm count, motility or morphology. ICSI is also used for patients who have had previous IVF cycles with failed fertilization.

Testicular/Epididymal Sperm Aspiration (TESA)

The surgical removal of sperm directly from the testes or the epididymis using a needle for aspiration. This procedure is used for men who have no sperm in their ejaculate or have had vasectomies in the past. Sperm obtained through TESE requires ICSI to ensure fertilization of the oocyte (egg).

Vaginal Oocyte Retrieval (VOR)

The medical term for an egg retrieval during an IVF cycle.

Ovarian Hyperstimulation Syndrome (OHSS)

A potential side effect of fertility medication during an IVF treatment cycle. Learn more about OHSS here.

Intrauterine Insemination (IUI)

technique that transfers sperm directly into the uterus, bypassing the vaginal and cervical defense mechanisms of the female reproductive tract to allow for better sperm delivery to the fallopian tubes. 

Learn more: Get your comprehensive guide to IUI treatment here!

In Vitro Fertilization (IVF)

A common fertility treatment method that involves stimulating the ovaries to produce a large number of follicles, an egg retrieval procedure, fertilization of those eggs with designated sperm in the lab, embryo growth monitoring, and embryo transfer once the intended parents are ready to attempt pregnancy.

Learn more: Explore IVF treatment with this step-by-step guide written by a fertility nurse.

Assisted Hatching (AH)

Assisted hatching is a procedure used in IVF treatment that can help the embryo “hatch” from its “shell” by creating a small crack in the zona pellucida (the transparent membrane surrounding the egg). It is believed that assisted hatching can help an embryo implant in the uterus, leading to higher pregnancy rates in some patients.

Reciprocal In Vitro Fertilization (RIVF)

This treatment method is similar to traditional IVF, except that one female partner's eggs are retrieved and fertilized, with the resulting embryos being transferred into the second female partner to attempt pregnancy.

Explore other LGBTQ+ family-building options and resources for your journey at Gay Parents To Be!

Elective Single Embryo Transfer (ESET)

The process of only transferring one embryo into the uterus (versus transferring multiple embryos at once). It is now considered best practice in IVF treatment to only transfer one embryo at a time. 

Gestational Carrier (GC)

Also referred to as a gestational surrogate (or simply a surrogate), a gestational carrier is a woman who carries and delivers a child for another couple or individual (the intended parents). When using a GC, the eggs used to create the embryos come from a different egg donor source, not the GC.

Learn more: Read Tim & Steve's surrogacy story and hear more about working with a GC!

Frozen Embryo Transfer (FET)

An embryo transfer using frozen embryos that have been thawed from a previous IVF cycle.


Want a deeper dive into IVF?

IVF Step by Step Guide


Pregnancy-Related Terms

Human Chorionic Gonadotropin (hCG)

A hormone produced by the placenta during pregnancy which helps thicken the uterine lining to support a growing embryo. hCG levels rise after conception and continue to do so until about 10 weeks in pregnancy.

Days Past Transfer (DPT)

The number of days after an embryo transfer in an IVF treatment cycle.

Two-Week Wait (TWW or 2WW)

The window of time between ovulation and a missed period when you're waiting to take a pregnancy test.

Get support and tips for navigating the two-week wait from one of our fertility nurses.

Last Menstrual Period (LMP)

The first day (onset of bleeding) of your last menstrual period before becoming pregnant.

Estimated Due Date (EDD)

The estimated date of delivery for a pregnant person, calculated based on their conception date.

Dilation & Curettage (D&C)

A surgical procedure in which the cervix is dilated (expanded) so that the uterine lining can be scraped with a curette (spoon-shaped instrument) to remove abnormal tissue or remnants from a miscarriage.

General Fertility-Related Terms

Polycystic Ovary Syndrome (PCOS)

A common endocrine disorder that causes hormonal imbalances in women of reproductive age. It can lead to dysfunctional ovulation, fertility issues, weight gain, insulin resistance (pre-diabetes) and an increase in the male hormone, testosterone. 

Diminished Ovarian Reserve (DOR)

A condition in which the ovaries lose their normal reproductive potential, leading to reduced fertility and an increase in trouble getting pregnant due to a loss of quality and/or quantity eggs available for fertilization. 10-30% of patients presenting to doctors with infertility struggle with DOR.

Luteinizing Hormone (LH)

A hormone produced and released by the pituitary gland. In women, it is responsible for ovulation and the maintenance of the corpus luteum. In men, it stimulates testosterone production and is important in the production of sperm cells.

Luteal Phase Deficiency (LPD)

Also called luteal phase defect, LPD is a deficiency of progesterone in the second half of the menstrual cycle which can lead to issues conceiving. Treatment involves supplementation with progesterone and other measures.

Want to learn even more? Explore RESOLVE's Fertility Acronyms dictionary!

5 Tips for Your Next Appointment

It can be overwhelming being bombarded with new words, treatment options, and terminology during an appointment. Here are some ways to make your next appointment a little more efficient and manageable.

  • Take a notepad with you to jot down answers or follow-up questions
  • Prepare ahead of time and bring a list of questions with you
  • Ask your doctor to slow down or repeat something if needed
  • Have someone you trust attend the appointment with you
  • Email or call your Care Team after the appointment for further clarification

Take this to your next appointment!

Get Your Downloadable Worksheet


Still feeling confused?

Don't be afraid to reach out to your Care Team at any time for clarification or ask your doctor to repeat or define terms you don't understand. Your team wants you to feel confident and comfortable with the information you're receiving. And you deserve to feel as empowered and confident as possible!

As you move through your fertility journey, you'll become more and more knowledgable, learning more terms, abbreviations and acronyms as you go. While no one wants to be a pro when it comes to infertility (let's be honest - no one even wants to have to learn what these terms mean), becoming familiar with all of this information can help you feel more in control and prepared.

Looking for more support? Illume Fertility offers free, one-on-one fertility support via our Patient Advocate, Lisa Rosenthal, who is a former fertility patient herself. If you're having a difficult time communicating with your Care Team, have concerns about your treatment or are experiencing other challenges, reach out to Lisa at (203) 240-6122 or email lrosenthal@illumefertility.com.

More Resources

Explore our extensive collection of articles, videos, eBooks, patient stories and more: