Pregnancy symptoms typically start to be felt about 1 to 2 weeks after conception, often around the time of implantation when the fertilized egg attaches to the uterus lining. Some early symptoms that may be felt this soon include mild cramping, light spotting (implantation bleeding), breast tenderness, fatigue, and nausea. However, symptoms vary widely between individuals, with some feeling nothing until later, and the most reliable early sign is usually a missed period about 4 weeks after conception. Hormonal changes driving these symptoms begin approximately 6 to 12 days after fertilization, which is when the body starts producing pregnancy hormones.

In summary: symptoms can begin roughly 1 to 2 weeks after conception but can vary from person to person, and some may not feel any symptoms until weeks later or until after a missed period.