We begin by recalling that embryo implantation is the process by which the embryo, already transferred to the mother’s uterus, adheres to the endometrium and penetrates inside. After this event, the development of the conceptus continues in your womb, which will increase in size and complexity over the next few weeks of pregnancy.
Implantation cramps
Implantation cramps are the pain you sometimes feel when a fertilized egg attaches (or nests) to the lining of your uterus. This operation can irritate the uterus, which will react by contracting and thus causing small pains in the lower abdomen. Implantation cramps usually last 1 to 3 days and start around day 21 of the cycle.
Implantation cramps occur in what would otherwise be the premenstrual period, and even they can lead to a little bleeding: if you are used to period pains you may mistake implantation cramps for the latter. For this reason it is important to pay attention and observe any other concomitant symptoms.
Symptoms of implantation cramps
For what has been said above, it is easy to understand that the symptoms you may experience during the implantation are also the symptoms of pregnancy:
- a missed menstrual cycle, the most evident and indicative sign
- unexpected mood swings and emotional changes
- an abdominal swelling
- sensitivity to certain foods
- nausea
- intestinal alterations such as constipation
For the complete list of early pregnancy symptoms, read our in-depth study: Early pregnancy symptoms .
Implant cramps, what to do
If you’re having what looks like implantation cramps and hope you’re pregnant but aren’t sure, try not to get too hopeful until you get a positive test . As we have seen above, there is a very fine line between implantation cramps and menstrual cramps in terms of symptoms.
So, if your period doesn’t arrive on time, take a pregnancy test if it’s at least 5 days late. If your period does come, you can be sure that the cramping is due to your period rather than early pregnancy.
When to worry
Usually, cramps are nothing to worry about. However, if the pain is severe, one-sided or lasts for more than several days, or if you experience significant vaginal bleeding, you should speak to your GP.
In the absence of periods, severe pain and abdominal swelling could also indicate endometriosis and ovarian disorders.
Katherine Johnson, M.D., is a board-certified obstetrician-gynecologist with clinical expertise in general obstetrics and gynecology, family planning, women’s health, and gynecology.
She is affiliated with the Obstetrics and Gynecology division at an undisclosed healthcare institution and the online platform, Maternicity.com.