The embryonic phase of development is complete by the end of the 10th menstrual or gestational week (this corresponds to 12 weeks following the onset of the last normal menstrual period).During this critical period of development, a single fertilized cell undergoes dramatic transformation as the cell mass evolves into major organs and a recognizable human form.

If the cervix is dilated, the pregnancy will certainly fail, although based on clinical examination, it is not usually possible to determine whether there are retained products of conception.

Some women with embryonic demise will be asymptomatic, and in these patients the diagnosis may be suggested based on subnormal uterine growth, inability to auscultate fetal cardiac activity, or failure of the human choriogonadotropin (h CG) level to increase at the expected rate.

During the first trimester of pregnancy, approximately 25% of women experience mild vaginal bleeding and/or cramping.

Pelvic examination usually reveals a closed and normal-appearing cervix.

In most instances, the clinical pelvic examination cannot determine the cause for the patient's symptoms.

Thus, the patient should be referred for a real-time pelvic ultrasonographic examination.This clinical presentation characterizes a threatened abortion.Analysis of women with these findings reveals that 50% of the pregnancies will fail and that the rest will have a normal outcome.If clinical dating suggests a gestational age (GA) of 8 weeks or older, some sonographers begin the ultrasonographic study using a transabdominal approach.Because of the complex sequence of events that occurs during this short time period, it is not unusual for complications to develop.Currently, transvaginal ultrasonography is the imaging examination of choice to evaluate the rapidly evolving intrauterine events that occur following implantation of the gestational sac and the development of a visible embryo.