RRM Glossary

The Achieving-Related Pregnancy Rate (ARPR) is a use-effectiveness statistic developed within the Creighton Model FertilityCare System to measure pregnancy outcomes specifically among couples who have transitioned from avoiding conception to actively attempting it.

Adenomyosis is the growth of tissue similar to the uterine lining into the myometrium, the muscle wall of the uterus.

Adhesiolysis is surgery that cuts and releases adhesions, bands of scar tissue inside the pelvis.

Adhesion prevention is the set of steps a surgeon takes to limit adhesions, bands of scar tissue, after abdominal and pelvic surgery.

Afollicularism is a cycle in which no ovarian follicle grows, even though menstrual periods still arrive on time.

Anovulatory cycles are menstrual cycles in which the ovaries do not release an egg, though bleeding may still occur and be mistaken for a normal period.

Anti-adhesion barriers are thin materials that a surgeon places to keep healing tissues apart.

AMH (anti-Müllerian hormone) is a hormone produced by small, growing follicles in the ovary.

Antioxidant therapy uses nutrients that protect reproductive cells from damage.

Antiphospholipid Syndrome (APS) is an immune disorder that makes the blood clot too easily and damages blood flow through the placenta.

AFC (Antral Follicle Count) is a transvaginal ultrasound measurement taken in the early follicular phase that counts small, fluid-filled follicles visible in both ovaries, typically 2 to 10 mm in diameter.

Assisted Reproductive Technology (ART) is any medical procedure that handles eggs or embryos to achieve a pregnancy.

Autoimmune and thrombophilic disorders are conditions that make blood clot too easily or disturb how the immune system accepts a pregnancy.

Azoospermia is the complete absence of sperm in the semen.

Basal body temperature (BBT) is the body's lowest resting temperature.

The Base Infertile Pattern (BIP) is a woman's own baseline of dryness or unchanging discharge before Peak, when pregnancy is unlikely.

The Billings Ovulation Method (BOM) is a mucus-only fertility awareness method developed by Australian physicians Drs. John and Evelyn Billings in the 1950s, based on the recognition that cervical mucus characteristics at the vulva change predictably across the cycle in response to estrogen and progesterone.

Fertility biomarkers are physical signs that change in a predictable pattern across the menstrual cycle.

Body literacy is a clear, informed understanding of the body's signs and of the fertility cycle.

Body mass index (BMI) is a measure that compares body weight with height.

CD138 (Syndecan-1) staining is a lab test on a sample of the endometrium, the lining of the uterus, that detects plasma cells.

Cervical factor infertility is difficulty conceiving that is linked to the cervix or its mucus.

Cervical mucus patterns are the changes in mucus that a woman sees and feels at the vulva across her cycle.

ChartNeo is a digital cycle-charting platform developed within the NeoFertility restorative reproductive medicine framework.

Chronic endometritis (CE) is a mild, persistent infection of the endometrium, the lining of the uterus.

Chronic pelvic pain (CPP) is pain in the pelvis that lasts six months or longer.

Clinical Endorphin Deficiency (CED) is a clinical pattern, formalized within NaProTechnology by Dr. Thomas W. Hilgers, characterized by chronic pelvic pain, mood symptoms including depression and anxiety, and difficulty recovering from physical or emotional stress.

Thrombophilia is an inherited or acquired condition that shifts the balance of the coagulation system toward clot formation, increasing the risk of pathological thrombosis.

The compounding pharmacist triad is the structured clinical relationship in NaProTechnology that connects three roles: the NaProTechnology -trained physician, the FertilityCare practitioner, and a licensed compounding pharmacist who prepares individualized isomolecular hormone formulations.

A comprehensive evaluation is a full search for the reasons a couple is not conceiving or has repeated pregnancy losses.

Cooperative Cyclic Hormone Replacement (ccHRT) is hormone replacement timed to support a woman's own cycle.

Cooperative Estrogen Replacement Therapy (CERT) is a NaProTechnology treatment that supports low estrogen during a woman's cycle.

Cooperative Progesterone Replacement Therapy (CPRT) is a NaProTechnology protocol that restores progesterone after ovulation.

CoQ10 (coenzyme Q10) is a natural nutrient that helps cells make energy.

The corpus luteum (CL) is a short-lived, hormone-producing gland that forms from the follicle after ovulation.

Corpus Luteum Deficiency (CLD) is a condition in which the corpus luteum does not produce enough progesterone.

Corrective care treats the cause of a health or fertility problem.

Couple-based treatment is the evaluation and care of both partners together.

The Creighton Model FertilityCare System (CrMS) is a method of tracking fertility by charting cervical mucus each day.

Cycle-timed diagnostics means scheduling tests on the right cycle days, found through fertility charting, rather than on random calendar dates.

D-Chiro-Inositol (DCI) is a sugar-like molecule that helps carry the insulin signal inside cells.

Delayed Rupture Syndrome (DRS) is an ovulation disorder, seen on ultrasound, in which the follicle ruptures late.

DHEA supplementation is the use of DHEA, a hormone the body converts into other sex hormones, to support the ovaries.

Diminished Ovarian Reserve (DOR) means the ovaries have fewer eggs left than expected for a woman's age.

DPO, or days post ovulation, is a day-counting convention that numbers days relative to the estimated day of ovulation, with ovulation assigned as 0 DPO, the following day as 1 DPO, and so on through the remainder of the cycle.

A dry day is a charted day with no mucus, no bleeding, and no sensation of wetness at the vulva.

Dysmenorrhea is painful menstruation.

Early pregnancy loss (EPL) is the spontaneous end of a confirmed pregnancy before 13 weeks.

Electrosurgery uses a high-frequency electric current to cut, seal, or vaporize tissue during reproductive surgery.

EMMA and ALICE are lab tests that check the bacteria in the endometrium, the lining of the uterus.

Empty Follicle Syndrome (EFS) is an ultrasound finding in which no cumulus oophorus is visible in an intact follicle before rupture.

Endometrial hyperplasia is an overgrowth of the endometrium, the lining of the uterus.

ERA (Endometrial Receptivity Analysis) is a lab test on a small sample of the endometrium, the lining of the uterus.

Endometrial thickness is the depth of the endometrium, the uterine lining, measured by ultrasound.

An endometrioma is an ovarian cyst that forms when endometriosis grows on or inside the ovary and fills with old menstrual blood.

Endometriosis is a disease in which tissue similar to the lining of the uterus grows outside the uterus.

The Essential Sameness Pattern (ESP) is a Creighton Model charting rule for women with daily discharge. It identifies days before Peak that look the same, day after day, as infertile. Yellow Stamps are the chart stickers that record those days.

Estrogen dominance is a clinical and conceptual term for an excess of estrogen without enough progesterone to balance it.

Estrogens are a group of steroid sex hormones.

Estrone (E1) is one of the three main estrogens that the human body makes.

Excision surgery is surgery that removes endometriosis completely, to its full depth.

The fallopian tube is a paired muscular and ciliated structure, roughly 10 to 12 centimeters in length, connecting each ovary to the uterine cavity and serving as the site of fertilization and early embryo transport.

Fallopian tube recanalization (tubal cannulation) is a brief procedure that opens a fallopian tube blocked near the uterus.

FEMM (Fertility Education and Medical Management) is a cycle-charting program that links observable body signs to medical care.

FEMM Education Levels are the three learning tracks of the FEMM program: teen, adult, and medical.

FEMM Medical Management is the clinical care level of the FEMM ( Fertility Education and Medical Management ) program.

The fertile window is the part of the cycle when intercourse can result in pregnancy.

The Fertilitas Study is a common nickname for a 2025 study of 1,310 couples with infertility.

Fertility Awareness-Based Methods (FABMs) are science-based methods to track and read fertility signs ( biomarkers ) in the menstrual cycle.

Fertility charting is the daily recording of fertility signs ( biomarkers ) by one standard method, such as the Creighton Model or another FABM.

Fertility-focused intercourse (FFI) is the timing of intercourse to the fertile window.

FertilityCare Practice is the named-method clinical discipline that integrates Creighton Model FertilityCare System charting instruction with NaProTechnology medical evaluation.

A FertilityCare Practitioner (FCP) is a credentialed teacher of the Creighton Model FertilityCare System for individuals and couples.

Follicle development is the process by which the ovaries grow a follicle, the fluid-filled sac that holds an egg, to ovulation each cycle.

A follicle maturation study is a series of transvaginal ultrasounds that tracks ovulation as it happens.

Follicle stimulation (ovulation induction) is the use of medicines to help follicles grow and to bring about ovulation.

Follicle-stimulating hormone (FSH) is a hormone that signals the ovaries to grow follicles, the sacs that hold eggs.

Follicular deficiency is an RRM term for a follicle that grows and ruptures on time but produces too little hormone.

The follicular phase is the first half of the menstrual cycle.

FSH desensitization is a working clinical model about why follicle-stimulating hormone (FSH) stays high.

Fulguration, ablation, and cauterization burn endometriosis at the surface but leave the lesion in place.

Functional and nutritional medicine is a whole-person approach to health.

Gonadotropins are protein hormones that control the ovaries and testes.

An hCG trigger is an injectable dose of human chorionic gonadotropin given during a monitored cycle to induce final follicular maturation and ovulation by mimicking the body's natural LH surge.

Heteromolecular artimones (HMA) are hormone-like drugs whose molecules differ from the hormones the body makes.

The holistic approach is the RRM principle that reproductive problems rarely arise from one body system alone.

Hormonal abnormalities are hormone problems that disrupt egg growth, ovulation, or early pregnancy.

Hormone replacement therapy (HRT) supplies estrogen, progesterone, or both to make up for falling hormone levels.

Human Chorionic Gonadotropin (hCG) is a hormone the early placenta produces soon after an embryo implants.

Hydrosalpinx is a fallopian tube that is blocked at its far end and filled with fluid.

Hydroxyprogesterones are hormones formed by adding a small oxygen and hydrogen group to progesterone.

Hyperandrogenism is the effect of excess androgens, the hormones present at higher levels in men, in a woman's body.

Hyperprolactinemia is a high blood level of the hormone prolactin.

Hypothyroidism is a condition in which the thyroid gland does not make enough thyroid hormone.

A hysterosalpingogram (HSG) is an X-ray test of the uterus and fallopian tubes.

Hysteroscopic septoplasty is surgery that removes a wall of tissue that divides the inside of the uterus.

A diagnostic hysteroscopy is an examination of the inside of the uterus with a thin, lighted camera.

Operative hysteroscopy is a procedure that uses a thin scope inside the uterus to treat problems found there.

The International Institute for Restorative Reproductive Medicine (IIRRM) is the global professional body for this field.

Immature Follicle Syndrome (IFS) is an ovulation disorder in which the follicle breaks open (ruptures) before it reaches mature size.

The Immune-Modifying Framework is a clinical approach for couples with repeated pregnancy loss or unexplained implantation failure.

Infertility is the absence of pregnancy in a couple after 12 months or more of regular intercourse without contraception.

Insulin resistance is a condition in which the cells of the body respond poorly to insulin.

Intracytoplasmic sperm injection (ICSI) is a laboratory procedure that places a single sperm directly inside a mature egg.

Intratubal pressure (ITP) is a quantitative measure of fallopian tube patency obtained by recording the pressure required to advance contrast through the tube during selective hysterosalpingography, converting the standard binary open-or-closed assessment into graded resistance data.

Asherman's syndrome is scar tissue inside the uterus that causes its walls to adhere to each other.

An intrauterine device (IUD) is a small, T-shaped contraceptive device placed inside the uterus.

Isomolecular hormones (IMH) are hormone medicines with the same molecular structure as the hormones the body makes.

Hysteroscopic isthmocele repair is a minimally invasive surgery that addresses a cesarean scar defect from inside the uterus.

Laparoscopic isthmocele repair is minimally invasive surgery that repairs a cesarean scar defect from outside the uterus.

Intrauterine insemination (IUI) places washed, concentrated sperm into the uterus through a thin tube, timed to ovulation.

In vitro fertilization (IVF) is a form of assisted reproductive technology (ART) that combines egg and sperm in a laboratory dish.

IVF vs. RRM is a framework that compares two very different responses to infertility.

Laparoscopic Ovarian Wedge Resection (LOWR) is surgery through small incisions that removes a wedge of the ovary to restore ovulation.

Diagnostic laparoscopy remains the most accurate surgical test for endometriosis.

Operative laparoscopy is minimally invasive surgery that uses a camera to treat disease the surgeon finds in the pelvis or abdomen.

Levothyroxine (L-T4) is a synthetic form of thyroid hormone taken as a pill.

A limited mucus cycle is a Creighton Model ( CrMS ) chart pattern in which cervical mucus is clearly reduced before ovulation.

A live birth is the complete delivery of a baby from the mother, after which the baby shows any sign of life.

Low-dose naltrexone (LDN) is naltrexone taken at very low doses.

The luteal phase (LP) is the second half of the menstrual cycle.

Luteal Phase Deficiency (LPD), also called luteal phase defect, is a hormonal condition in which the corpus luteum produces insufficient progesterone, the luteal phase is too short, or the endometrium fails to respond adequately to progesterone, impairing implantation and early pregnancy support.

Luteinized Unruptured Follicle (LUF) syndrome occurs when the dominant follicle begins producing progesterone but never ruptures to release its egg.

Luteinizing hormone (LH) is a hormone produced by the pituitary gland at the base of the brain.

Male factor infertility refers to any condition arising from the male partner that reduces a couple's ability to conceive, including abnormalities of sperm count, motility, morphology, sperm DNA integrity, hormone levels, or reproductive anatomy.

The Marquette Method is a fertility awareness method that tracks fertility with a home hormone monitor.

The Marquette Method Clinical Protocol is a structured approach to fertility charting developed at the Marquette University Institute for Natural Family Planning, principally by Dr. Richard Fehring and colleagues beginning in the late 1990s.

Mature reproductive age is a clinical designation for women aged 35 and older who are attempting pregnancy, acknowledging that fertility potential, egg quality, and time-to-pregnancy change meaningfully as the ovarian reserve established before birth continues its decline, at an accelerating pace through the mid-thirties and beyond.

Menopause is the permanent end of menstrual periods.

Methylated folate (L-methylfolate) is the active form of folate, a B vitamin.

Microsurgery is surgery done under magnification, with fine tools and delicate stitches, on small or fragile structures.

Mini-laparotomy is open surgery through a small, low incision across the abdomen.

Minimally Invasive Gynecologic Surgery (MIGS) is a Focused Practice Designation (FPD) from the American Board of Obstetrics and Gynecology (ABOG). The American Board of Medical Specialties (ABMS) approved MIGS as an FPD in March 2017.

Molimina is a group of mild, predictable symptoms before a period that reflect normal progesterone activity.

The Mucus Cycle is the run of fertile-type cervical mucus within a single menstrual cycle.

The Mucus Cycle Score (MCS) is a number derived from Creighton Model ( CrMS ) charts that grades the mucus of a cycle.

The mucus pattern is the series of changes in cervical fluid that a woman can observe across one menstrual cycle.

Mucus quality descriptors are the standard terms that fertility awareness-based methods (FABMs) use to record how cervical mucus looks and feels.

Myo-inositol is a natural compound, similar to a sugar, that helps the cells of the body respond to insulin.

Myomectomy is surgery that removes uterine fibroids (leiomyomas) and preserves the uterus.

NaPro Medical is the non-surgical treatment arm of NaProTECHNOLOGY, guided by cycle charting.

NaPro Surgery is the surgical branch of NaProTECHNOLOGY.

NaProTECHNOLOGY (Natural Procreative Technology) is a women's health science that works with the menstrual cycle.

The NaProTechnology Fellowship is a one-year training program for physicians, run by the Saint Paul VI Institute.

A NaProTechnology Medical Consultant (NFPMC) is a physician trained to interpret Creighton Model charts, run the NaProTechnology diagnostic workup, and treat the reproductive disease those charts reveal.

Prematurity Prevention is a NaProTechnology clinical protocol developed by Dr. Thomas W. Hilgers for managing pregnancies at elevated risk for preterm birth.

NaProTechnology ( NaPro ) is the most established and most studied approach within Restorative Reproductive Medicine.

Natural Family Planning (NFP) is a way to achieve or avoid pregnancy by tracking the body's own fertility signs.

Natural fertility is a couple's own ability to conceive through natural conception.

Natural killer (NK) cells are lymphocytes of the innate immune system with two populations relevant to reproductive medicine: circulating NK cells (CD56dim), which perform immune surveillance in the bloodstream, and uterine NK cells (CD56bright), which are the predominant immune cells in the endometrium during the secretory phase and early pregnancy.

Near Adhesion-Free Reconstructive Pelvic Surgery (NARPS) is a method of pelvic surgery that limits the formation of new scar tissue.

Near-contact laparoscopy is a method of examining the pelvis with the camera held very close to the tissue.

NeoFertility is a restorative reproductive medicine framework developed at a clinic in Dublin, Ireland. It uses cycle charting, hormone testing, and surgery to find and treat the causes of infertility, recurrent miscarriage, and high-risk pregnancy.

Neosalpingostomy is surgery that creates a new opening at the blocked far end of a fallopian tube.

Nutritional and lifestyle medicine examines how diet, sleep, stress, and daily habits shape fertility.

Oligospermia (also oligozoospermia) is a suboptimal concentration of spermatozoa in the ejaculate.

OAT syndrome is the combination of low sperm count, poor sperm motility, and abnormal sperm shape in the same man.

Omega-3 fatty acids are healthy fats found mostly in oily fish and fish oil.

An oral contraceptive (OC) is a hormone pill taken by mouth to prevent pregnancy.

Ovarian hyperstimulation syndrome (OHSS) is a reaction to fertility drugs that overstimulate the ovaries.

Ovarian reserve is the pool of follicles that remain in the ovaries. Follicles are the small sacs in the ovary that hold eggs. Three markers estimate that pool: AMH, AFC, and basal FSH.

Ovulation Confirmation is the clinical work of proving that an egg was actually released, rather than assuming it was.

Oxidative stress is a build-up of reactive oxygen species (ROS), harmful oxygen molecules, inside the body.

Partial Rupture Syndrome (PRS) is an ovulation disorder in which the follicle begins to open but never fully collapses.

Patient-centered care is care built around the values and needs of each person and the information that person wants.

Peak +7 Progesterone (P+7) is a blood test that measures progesterone about one week after ovulation.

Peak Day is the last day of a cycle with clear, stretchy, or slippery cervical mucus.

The peak symptom is the last day in a menstrual cycle on which cervical mucus is observed as clear, stretchy, or lubricative, regardless of the total amount of discharge present.

PEARS is a form of pelvic surgery that removes disease and rebuilds normal anatomy.

Pelvic adhesions are bands of scar tissue that form between organs in the pelvis and bind them together.

Pelvic floor physical therapy (PFPT) is hands-on rehabilitation for the muscles that support the pelvis.

Perimenopause is the period of years before menopause, when ovarian function declines and cycles become irregular.

In RRM, personalized treatment means the care plan follows the couple's own test results.

PGT-A (Preimplantation Genetic Testing for Aneuploidy) is a laboratory procedure performed on an embryo biopsy during IVF to screen for chromosomal aneuploidy before transfer.

Polyendocrine metabolic ovarian syndrome (PMOS), formerly polycystic ovary syndrome (PCOS), is the most common hormone disorder in women of reproductive age.

PMOS / PCOS phenotypes are the four subtypes of polyendocrine metabolic ovarian syndrome (PMOS), formerly polycystic ovary syndrome (PCOS).

The Point of Change (POC) is the cycle day when a woman's Base Infertile Pattern is broken for the first time: discharge changes in character, sensation shifts, and the fertile window opens.

Poor cervical mucus production is the production of too little fertile mucus, or of mucus that functions poorly.

The post-peak phase is the part of the cycle that begins the day after Peak Day and ends the day before the next period.

Postpartum fertility is the return of ovulation and the chance of pregnancy after a baby is born.

The pre-peak phase runs from the first day of bleeding through Peak Day.

Premature ovarian insufficiency (POI) is the loss of normal ovarian function before age 40.

Premenopause is the stage of life before perimenopause, when cycles are regular and ovulation occurs in most months.

Premenstrual Bleeding (PMB) is a Creighton Model chart sign: brown spotting or light bleeding before a period starts.

Premenstrual syndrome (PMS) is a pattern of cyclical physical, mental, and emotional symptoms in the luteal phase, the part of the cycle after ovulation.

Preterm birth is a birth that occurs before 37 completed weeks of pregnancy.

Progesterone as a neurosteroid refers to progesterone's role as a brain-active hormone that operates throughout the body, not merely within the uterus.

Progestin vs. Progesterone names the difference between two kinds of drugs used in reproductive care.

Progestins are synthetic drugs that act like the body's own progesterone.

Recurrent Pregnancy Loss (RPL) is defined as two or more clinical pregnancy losses before 20 weeks of gestation.

Reproductive Endocrinology is the study of how hormones control reproduction.

Reproductive health optimization is the RRM goal of supporting the health and function of the whole reproductive system.

The Reproductive Health Research Institute (RHRI) is the research and training arm of the FEMM framework.

Reproductive Immunology is the study of how the immune system affects implantation, pregnancy loss, and fertility.

In RRM, "restorative" describes care that repairs and supports the body's own reproductive function.

Restorative andrology identifies the cause of male factor infertility and treats it.

Restorative Reproductive Medicine (RRM) is care that finds and treats the health conditions that cause reproductive problems in women and men.

The retrograde menstruation theory is a long-held explanation of how endometriosis begins.

Root cause diagnosis is the core RRM principle that a reproductive health problem points to a cause that a clinician can identify.

RRM Outcomes: Published Evidence documents the live birth rates achieved by Restorative Reproductive Medicine and NaProTECHNOLOGY in peer-reviewed literature.

S-MAP (Systematic Mapping of the Abdomen and Pelvis) is an operative protocol developed within NaProTechnology, first described by Dr. Thomas W. Hilgers, that requires a structured, sequential inspection of all abdominal and pelvic regions before any surgical intervention begins.

A saline infusion sonohysterogram (SIS) is an ultrasound that uses sterile saline, a salt water solution, to show the inside of the uterus.

Secondary infertility is the inability of a couple to conceive again after a previous pregnancy.

Selective salpingography tests each fallopian tube, one at a time, to determine whether it is open.

Semen analysis is a laboratory test that evaluates a man's sperm and semen. It is the first test used to look for a male cause of infertility.

A shortened luteal phase is a phase after ovulation that is too short to support a pregnancy.

Sonographic ovulation classification is a serial transvaginal ultrasound framework, developed within NaProTechnology practice, that characterizes the quality of the periovulatory event and distinguishes anatomically normal ovulation from a set of named abnormal patterns, one of them anovulatory.

Sperm DNA fragmentation (SDF) refers to breaks in the DNA inside sperm cells. The DNA Fragmentation Index ( DFI ) is the lab result that shows how much of a sperm sample is affected.

Sperm DNA fragmentation (extended) refers to the laboratory tests that detect breaks and damage in the DNA inside sperm.

The sympto-hormonal method is a method of cycle charting that adds home urine hormone tests to physical signs.

The Sympto-Thermal Method (STM) is a method of fertility tracking that uses two body signs: cervical mucus and waking body temperature.

Tail-End Brown Bleeding (TEB) is brown or black spotting for two or more days at the end of a period.

The Peak Plus Series is a NaProTechnology and Creighton Model protocol of serial serum progesterone draws timed to specific days after the identified Peak Day, designed to characterize progesterone production across the full arc of the luteal phase rather than at a single point in time.

Thyroid is a small, butterfly-shaped gland at the front of the neck.

Thyroid-Stimulating Hormone (TSH) is a hormone produced by the pituitary gland at the base of the brain.

Time to pregnancy (TTP) is the number of months from the time a couple begins trying to conceive until pregnancy is confirmed.

Transcervical catheterization of the fallopian tubes (TCFT) is an X-ray-guided procedure that evaluates and clears a partly blocked tube.

Transdermal estrogen is estradiol delivered through the skin, as a patch, gel, or cream.

Tubal factor infertility is difficulty conceiving because the fallopian tubes are blocked or damaged.

Tubal ligation reversal (tubo-tubal anastomosis) is a microsurgical procedure that reconnects the segments of the fallopian tube separated or occluded during prior sterilization, restoring natural tubal patency and allowing natural conception to resume.

"Unexplained infertility" is a clinical label assigned when standard evaluation, which typically includes semen analysis, ovulation assessment, hormonal screening, and tubal patency testing, returns normal results.

Uterine fibroids (leiomyomas) are noncancerous growths of muscle tissue in the wall of the uterus.

An isthmocele is a thin area in the uterine wall where a previous cesarean scar did not heal to full thickness.

A uterine septum is a wall of tissue that divides the cavity of the uterus.

The Vaginal Discharge Recording System (VDRS) is the standard way a woman records what she sees and feels at the vulva each day.

A varicocele is a cluster of enlarged veins in the scrotum, around the testicle.

Vasectomy reversal is surgery that reopens the vas deferens after a vasectomy, so sperm can reach the semen again.

Vitamin D is a vitamin that the body converts into a hormone.

Vulvar observation is the practice of checking cervical mucus at the vulva, the external genital area outside the vagina.

The window of implantation (WOI) is the few days each cycle when the endometrium, the lining of the uterus, can accept an embryo.