Implantation Cramps or PMS: How to Tell the Difference

If you are anxiously waiting for an early sign of pregnancy, implantation cramps may be a welcome experience. Unfortunately, implantation cramps and premenstrual syndrome (PMS) share a lot of the same signs and symptoms. Unlike pregnancy, PMS is not a welcomed experience. So how can you tell the difference?

The American Pregnancy Association (APA) explains that implantation cramps occur when  a fertilized egg implants inside your uterus. Not everyone has implantation cramps, but many women do. Some women will also have some vaginal bleeding along with implantation cramps. Implantation cramps and bleeding occur about 6 to 12 days after ovulation, about the same time as PMS and your period.

According to the Mayo Clinic, PMS is common with about three-fourths of women experiencing it at some time. The cause of PMS is not completely known, but it is probably related to changes in hormones and changes in brain chemicals, and in some cases, it may be linked to depression. Like implantation cramps, PMS occurs around the time of your period and is followed in short order by vaginal bleeding.

Adding to the confusion, both pregnancy and PMS can have other symptoms in common. These include swollen and tender breasts, fatigue, headache, appetite changes, nausea, aches and pains, constipation, and mood swings.

How Are PMS and Implantation Cramps Different? 

There are a few reliable ways to tell the difference:

  • PMS cramps are usually more severe. Cramps from implantation are mild or may be described as a prickle, pulling, or tingle rather than a painful cramp.
  • Menstrual bleeding after PMS is bright red or dark red. Implantation bleeding is light pink or rust-colored.
  • Menstrual bleeding may have clots in it. Implantation bleeding never has any clots.
  • The amount of menstrual bleeding differs from woman to woman but most women will soak a pad or tampon during a period. Implantation bleeding is light bleeding or spotting.
  • Implantation bleeding lasts only one or two days. Menstrual bleeding lasts four to seven days.
  • PMS may cause other symptoms like tension, anxiety, crying spells, insomnia, bloating, acne, and alcohol intolerance. These symptoms are unlikely with implantation cramps.

When to Call the Doctor

If you think you have implantation cramps, take a home pregnancy test in one to two weeks. If your test is positive, call your doctor for pregnancy confirmation testing. Other times to call your doctor include:

  • If PMS symptoms are severe enough to interfere with daily living
  • If you have cramping or bleeding after confirming your pregnancy
  • If you have cramping or bleeding between menstrual periods
Christopher Iliades
Dr. Chris Iliades is a medical doctor with 20 years of experience in clinical medicine and clinical research. Chris has been a full time medical writer and journalist since 2004. His byline appears in over 1,000 articles online including EverydayHealth, The Clinical Advisor, and Healthgrades. He has also written for print media including Cruising World Magazine, MD News, and The Johns Hopkins Children's Center Magazine. Chris lives with his wife and close to his three children and four grandchildren in the Boston area.

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