We’re Talking All Things Periods. Period.

Neeru Singh, MD
March 10, 2021
7 min

Ask most females about the first time they bled and more likely than not they have a story ready to go. Getting your period is a major rite of passage and once it starts, it will continue to play a role in your overall health and well-being EVERY MONTH for decades to come.

While periods can wreak havoc on your body, serving up mood swings, cramps, discomfort, and maybe a few embarrassing moments, they are also a monthly reminder of what the female body is fully capable of...creating human life. 

Stages of the Menstrual Cycle

Each month, one of your two ovaries releases an egg — a process called ovulation. At the same time, hormonal changes prepare the uterus for pregnancy. If ovulation takes place and the egg isn't fertilized, the lining of the uterus sheds through the vagina. This is known as a menstrual period.

The menstrual period is just one phase of your menstrual cycle, the monthly series of changes a woman's body goes through in preparation for the possibility of pregnancy. This cycle is typically about 28 days long, but varies from woman to woman and can ebb and flow depending on factors like age, health, and stress levels. 

Let’s take a closer look at the four stages of the menstrual cycle:

Menstrual phase

During this time, estrogen and progesterone hormones drop. Your body realizes it isn’t pregnant. The uterus sheds the thickened lining of its walls, since it doesn’t need to support a pregnancy.

Period symptoms can  include:

  • Cramps 
  • Bloating
  • Mood swings and irritability
  • Headaches
  • Tiredness
  • Low back pain
  • Sensitive breasts

Follicular phase

Begins the first day of your period and ends when you ovulate. 

The ovaries produce follicles, each of which contains an immature egg. The healthiest egg from this production begins to mature, setting off a rapid increase in estrogen that signals the uterus lining to thicken, creating the right environment for an embryo to grow.

Ovulation phase

This typically occurs around Day 14, or right in the middle of your 28-day cycle. The ovary releases a mature egg which travels down the fallopian tube toward the uterus to be fertilized. 

Luteal phase

After the egg has left the ovary, the empty follicle that’s left makes hormones that signal the lining of the uterus to prepare for a fertilized egg. If there is no pregnancy, your body releases hormones that cause the uterine lining to break down. It eventually flows out of the body during your menstrual period. 

When Do Girls Typically Start Their Period?

First thing’s first—every girl’s body is different and will develop on its own schedule.

Most girls will start their period around the age of 12, and any time between 10 and 15 years is considered normal. 

Signs you may be close to starting your first period:

Breast development: Usually starts to occur a few years before you get your period.

Vaginal discharge: Starts about six months before your period.

What Happens When You’re on Birth Control?

It isn’t uncommon for girls and women to experience painful periods, periods with abnormally heavy bleeding, or periods that are irregular. Sometimes, these symptoms can be managed with hormonal birth control.

Hormonal birth control methods include oral pills, intrauterine devices (IUDs), shots, or the use of a vaginal ring. 

Birth control methods can help regulate the length and severity of your periods, plus reduce painful symptoms like cramping and headaches. Be sure to talk to your healthcare provider about options that work best for you.

Health and Environmental Factors Can Affect Your Period

You can experience abnormal or heavy bleeding, or even the absence of your period for a ton of different reasons. The National Institutes of Health offer a complete list of factors here. 

Irregular period are often caused by:

  • Perimenopause (generally in the late 40s and early 50s)
  • Anorexia nervosa, bulimia, and/or excessive exercise
  • Thyroid dysfunction
  • Cushing's syndrome 
  • Medications

Heavy bleeding can be associated with: 

  • Polycystic ovary syndrome 
  • Uterine fibroids (benign growths of uterine muscle)
  • Endometrial polyps 
  • Adenomyosis 
  • Non-hormonal IUDs
  • Pregnancy miscarriage

Painful menstrual periods can be caused by:

  • Endometriosis 
  • Uterine abnormalities
  • Copper IUDs (not all IUDs)
  • Pelvic scarring due to sexually transmitted infections, such as chlamydia or gonorrhea
  • Heavy menstrual flow

Your Period and Pregnancy

Words of caution here: You can become pregnant from having sex while on your period. Here’s why. Pregnancy happens when two specific moments match up: ovulation and fertilization. Because ovulation times vary from woman to woman, and can vary for the same woman over different times in her life, it’s possible to get pregnant when you’re on your period. 


You won’t have your period for your whole life. When a woman is in her late 40’s and early 50’s, her reproductive hormones begin to rapidly decrease. She’ll go through perimenopause and then she’ll reach menopause—a time signaled by the absence of a menstrual period for 12 months or more. 

Talking to Your Provider About Your Period

If your period changes drastically over a relatively short period of time, it’s a good idea to contact your nurse or doctor. It’s normal to experience phases over the years when, for instance, your period is a little heavier or lighter, or lasts fewer days. 

Reasons to contact your provider:

  • You’re consistently spotting between periods
  • You develop severe pain during your period
  • Your periods suddenly stop for more than 90 days — and you're not pregnant
  • Your periods were regular but now they’re erratic 
  • Your period lasts for more than seven days
  • You’re changing your pad or tampon every hour or two (because it’s soaked through)
  • Your periods are really close together or too far apart (less than 21 days or more than 35 days)
  • You suddenly get a fever and feel sick after using tampons

Woman's Health & Wellness at Carbon Health

No matter where you are on your life journey, Carbon Health’s healthcare providers are here to help support you through all your women’s healthcare needs. Book an appointment today to talk to a provider about what you’re going through and they will be there to help, support, and guide you every step of the way.


Liked what you read? Learn more by downloading the Carbon Health app or visiting carbonhealth.com.

Neeru Singh, MD

Neeru Singh, MD, is a Medical Director at Carbon Health. As a primary care physician, she enjoys educating and guiding patients on important health decisions.


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