The First 20 Signs of Pregnancy
The very first signs of pregnancy appear even before your period is missed, a few days after conception. So, if you closely monitor changes in your body, you may notice the first signs of pregnancy even before your period is missed. Every pregnancy is different, so every woman experiences pregnancy differently. This doesn't mean you will experience all of the symptoms listed above.
However, a complete absence of early pregnancy symptoms in the first week is very rare, and this is due to a woman's increased sensitivity to hCG (a hormone produced by the embryo during the first 14 days of its development).
If a woman has a regular menstrual cycle, a missed period is the first reliable sign of pregnancy.