Implantation is when a fertilized egg attaches to the uterine lining in early pregnancy.
This typically occurs six to 12 days after having unprotected sex.
The process is not intense or painful, so you may not notice when implantation happens.
Illustration by Tara Anand for Verywell Health
But some subtle symptoms can occur.
Most people do not feel it happening.
What Makes Implantation Different From PMS Symptoms?
Implantation symptoms are subtle and occur around the same time, making it easy to mistake them for PMS.
PMS symptoms include:
PMS belly cramps are stronger and more persistent than implantation cramps.
These cramps can occur throughout the first trimester.
Some people mistake implantation bleeding for their period.
But with implantation bleeding, the flow and color are lighter, and it rarely produces blood clots.
It lasts only one to two days rather than three to seven days, like a period.
Do You Test Positive for Pregnancy Before Implantation?
A home pregnancy test will not indicate a positive before implantation.
Pregnancy tests work by detecting human chorionic gonadotropin (HCG), a hormone that the developing placenta produces.
The following conditions and events can mimic implantation symptoms.
Complications
Complications can arise during early pregnancy.
Two concerns are miscarriage and ectopic pregnancy.
Miscarriageis the loss of a pregnancy before 20 weeks.
Symptoms may include:
Anectopicpregnancyis when the fertilized egg implants outside the uterus.
This can lead to severe complications, including rupture of the fallopian tube and internal bleeding.
Ectopic pregnancies require immediate medical attention.
These symptoms occur around six to 12 days after conception.
Because symptoms can overlap with other conditions, they are not definitive indicators of pregnancy.
The most reliable way to confirm pregnancy is through a pregnancy test and consultation with a healthcare provider.
American College of Obstetricians and Gynecologists.Bleeding during pregnancy.
Dhamecha R, Pajai S, Bhasin T.Acute abdomen in pregnancy: a comprehensive review of diagnosis and management.Cureus.
2023;15(6).
2020;21(6):1973. doi:10.3390/ijms21061973
Kim Su-Mi, Kim Jong-Soo.A review of mechanisms of implantation.Dev.
2019;51(1):86-93. doi:10.1093/labmed/lmz039
Office on Womens Health (OASH).Pregnancy tests.
2017;3(4).
doi:10.1016/j.heliyon.2017.e00282
Nezhat C, Vang N, Tanaka P.Optimal management of endometriosis and pain.Obstetrics & Gynecology.
2019:134(4):834-839. doi:10.1097/AOG.0000000000003461
Delamater L, Santoro N.Management of the perimenopause.Clinical Obstetrics & Gynecology.
2017;15(9):535-542.
The American College of Obstetricians and Gynecologists.Ectopic pregnancy FAQs.
