What Are the First Symptoms of Pregnancy?

Pregnancy symptoms differ for each woman, but early signs typically include missed menstrual periods, spotting, tender breasts, headaches and nausea, according to the American Pregnancy Association. Women can experience different symptoms with each subsequent pregnancy, and some pregnancy indicators are associated with other conditions, so an official test is always recommended by physicians.

A missed period may be the first pregnancy symptom if conception takes place just before a woman's normal menstruation time. However, pregnancy can cause cramping and spotting, or light vaginal bleeding, within six to 12 days of conception, the APA states. Implantation bleeding may occur when a newly fertilized embryo comes to rest on the uterine lining. These symptoms are easily overlooked because they resemble menstruation.

Sudden changes in hormonal levels, including progesterone, may bring on fatigue, constipation, dizziness, headaches, excessive urination and breast soreness, according to WebMD. Women may feel more tired than usual and suffer lower back pain. A woman's breasts may swell and become fuller, making them ache or feel tender and tingly.

The infamous "morning sickness" can happen throughout the day, but it doesn't affect all women. Hormonal changes cause the stomach to empty out more slowly, triggering bouts of nausea, WebMD states. Women may also develop a temporary aversion to a specific food and feel nauseous whenever they see or smell it.