Amenorrhea occurs.

Breasts begin to change.

Immunologic pregnancy tests become positive: Radioimmunoassay test results are positive a few days after implantation; urine human chorionic gonadotropin test results are positive 10 to 14 days after amenorrhea occurs.

Nausea and vomiting begin between the fourth and sixth weeks.

Goodell’s sign occurs (softening of the cervix and vagina).

Ladin’s sign occurs (softening of the uterine isthmus).

Hegar’s sign occurs (softening of the lower uterine segment).

Chadwick’s sign appears (purple-blue coloration of the vagina, cervix, and vulva).

McDonald’s sign appears (easy flexion of the fundus toward the cervix).

Braun von Fernwald’s sign occurs (irregular softening and enlargement of the uterine fundus at the site of implantation).

Piskacek’s sign may occur (asymmetrical softening and enlargement of the uterus).

The cervical mucus plug forms.

The uterus changes from pear-shaped to globular.

Urinary frequency and urgency occur.