Implantation Cramps

Definition - What does Implantation Cramps mean?

Implantation cramps are cramps that occur around as a result of a fertilized egg burrowing into the wall of the uterus. Implantation cramps are normally brief, lasting only one or two days. They may be accompanied by small amounts of bleeding.

FertilitySmarts explains Implantation Cramps

Implantation can occur anywhere from 5-14 days after an egg is fertilized by sperm. Implantation cramps, which occur late in that window, may be mistaken for premenstrual cramps.

Implantation cramping can often be distinguished from premenstrual cramping by:

  • Brevity and mildness. Implantation cramps may last only a few minutes, and usually do not last longer than two days. Some women do not experience any cramping with implantation, and instead notice a lack of normal premenstrual cramping.
  • Quality of sensation. While some women describe implantation cramps as feeling similar to premenstrual cramps, others describe a "pulling," "pricking," or "tingling" sensation.
  • Brevity and mildness of bleeding. Implantation cramps are sometimes accompanied by implantation bleeding, which can be mistaken for menstrual bleeding. However, implantation bleeding is usually lighter than a normal period, and lasts no more than two days. Bleeding may also be entirely absent.

Implantation cramping and bleeding are caused by chemical changes that occur when the fertilized egg, or zygote, makes contact with the uterine wall.

Contact with the zygote causes chemical signaling cascades within the uterine tissue. These cascades prevent the body from shedding the uterine lining, and begin preparing it for pregnancy. They also cause mild cramping and bleeding in some women.

Implantation cramping should never be more severe than normal premenstrual cramping. Severe or persistent abdominal pain when early pregnancy is possible could indicate ectopic pregnancy or other complications, and should be investigated promptly by medical providers.

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