Cycle Glossary A–Z
The key terms around your cycle and menstruation — explained clearly and simply.
A
Amenorrhea
The absence of menstruation for several months — either because periods never started or because they have temporarily stopped.
B
Basal body temperature
Your body temperature measured right after waking. It rises slightly after ovulation and helps identify the phases of your cycle.
C
Cervical mucus
The secretion from the cervix that changes over the cycle, becoming clear and stretchy around ovulation.
Corpus luteum
The structure that forms from the follicle after ovulation and produces progesterone to support the second half of the cycle.
E
Endometriosis
A condition in which tissue similar to the uterine lining grows outside the uterus and can cause symptoms.
Read the article →Endometrium
The inner lining of the uterus that builds up during the cycle and is shed during menstruation.
Estrogen
The key hormone of the first cycle half; among other things it builds up the uterine lining.
F
Fibroid
A benign muscle growth of the uterus that can cause symptoms depending on its size and location.
Follicle
A fluid-filled sac in the ovary in which an egg matures.
Follicular phase
The first half of the cycle, from the first day of bleeding to ovulation, when a follicle matures and estrogen rises.
FSH
Follicle-stimulating hormone stimulates the growth of follicles in the ovary.
H
Hormonal IUD
A contraceptive placed in the uterus that releases a progestin locally and often reduces bleeding.
I
Implantation
The attachment of a fertilized egg to the uterine lining at the start of a pregnancy.
L
LH
Luteinizing hormone; a sharp rise (the LH surge) triggers ovulation.
Luteal phase
The second half of the cycle after ovulation, shaped by progesterone from the corpus luteum.
M
Menopause
The point of the final menstrual period — confirmed retrospectively after twelve months without bleeding.
Menstrual cycle
The span from the first day of one period to the day before the next — around 28 days on average, but highly individual.
Menstruation
The regular shedding of the uterine lining with bleeding at the start of the cycle.
O
Ovulation
The release of a mature egg from the ovary, usually around the middle of the cycle.
P
PCOS
Polycystic ovary syndrome — a hormonal condition that can make the cycle irregular.
Perimenopause
The transitional phase of hormonal fluctuations before menopause.
Read the article →Period pain
Cramping lower-abdominal pain around menstruation, caused by the contraction of the uterus.
Read the article →PMDD
Premenstrual dysphoric disorder — a severe form of PMS with pronounced emotional symptoms.
PMS
Premenstrual syndrome — physical and emotional symptoms in the days before menstruation.
Progesterone
The hormone of the second cycle half; it stabilizes the uterine lining and prepares it for possible implantation.
T
TENS
Transcutaneous electrical nerve stimulation — a gentle low-current method that can ease pain, for example period cramps.
Read the article →The change (menopause transition)
Everyday term for the transitional years around menopause, as ovarian function gradually declines.
U
Uterus
The muscular hollow organ in which a pregnancy can develop and whose lining produces menstruation.