The female reproductive system

The female reproductive system

Medically reviewed by Maureen Farrell, MD

The female reproductive system

  • Uterus

  • Ovaries

  • fallopian tubes

  • Cervix

  • Vulva

  • Msgr

  • Major lips

  • Smaller lips

  • Clitoris

  • Urethra

  • Vaginal opening

Menstruation (the period)

It typically begins in females between the ages of 11 and 16

The average cycle is around 28 days but can range from 21 to 35 days

The cycle begins on the first day of the period and ends on the first day of the following period

The menstrual cycle occurs in three phases

or Follicular phase (1st day of the cycle until ovulation)

  • Days 1 to 5

    • The uterine lining breaks down and is pushed out of the body through bleeding (menstruation)

  • Days 6 to 10

    • Estrogen rises and the lining of the uterus thickens

    • Follicle Stimulating Hormone (FSH) causes follicles (small cysts) to grow and eggs grow inside those follicles

    • Follicles release more estrogen, helping the lining of the uterus to thicken and prepare for a fertilized egg

  • Days 10 to 14

    • One follicle will form a mature egg

or Ovulatory phase (days 14 to 16)

  • An estrogen surge causes a rise in luteinizing hormone (LH)

  • This increase causes a follicle to open and release an egg which is swept out of one of the fallopian tubes. This is called ovulation.

  • If unprotected intercourse occurs, the egg can be fertilized when a sperm and egg combine

  • If the egg is not fertilized, it will dissolve over the next few days

or Luteal phase (days 15 to 28)

  • The follicle that contained the egg becomes the corpus luteum, which produces the hormone progesterone

  • Progesterone keeps the lining of the uterus healthy and supports the growth of a pregnancy

  • The egg moves from the fallopian tube to the uterus

    • If the egg is fertilized and implants itself in the uterus, the person will become pregnant

    • If the egg passes through the uterus, the corpus luteum stops producing progesterone, which causes the lining of the uterus to break down and fall off during the menstrual cycle, and the cycle starts all over again


  • The first day of pregnancy is dated from the first day of your last period before becoming pregnant

  • A full-term pregnancy lasts 40 weeks (280 days) and is divided into 3 trimesters

    o 1st trimester: implant until week 12

    o 2nd trimester: weeks 13 to 28

    o 3rd trimester: weeks 29 to 40


  • The 12 weeks following delivery are the 4th trimester.

  • Breast milk begins to come several days after delivery.

  • Lochia, a menstrual discharge that contains blood, mucus and uterine tissue, lasts for several weeks.

  • The uterus will shrink from about 2.5 pounds (the size of a watermelon) immediately after birth to about 2 ounces (the size of a lemon) in about 6 weeks.

  • Estrogen levels drop and can lead to baby blues or postpartum depression, which is more severe and lasts longer. Postpartum depression affects up to 1 in 5 women after giving birth.


  • A natural process that typically occurs between the ages of 45 and 55, marking the end of a woman’s menstrual cycle and the end of the ovaries releasing eggs

  • A woman is said to be in menopause when she has not had her period for 12 months.

  • It begins with perimenopause, the transitional period before menopause when estrogen levels begin to decline. Perimenopause often begins in the mid-40s, but can begin for some women in their 30s.

Talk to your doctor if you have questions about your reproductive cycle or need help managing your symptoms.