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First and Second Trimester Pregnancy Loss

First Trimester Pregnancy Loss

Preclinical

Fertilization usually occurs in the fallopian tube and, by the sixth day, implants into the endometrium

This pregnancy will not be recognized clinically for 1-2 weeks; therefore, loss of an embryo prior to about 3 weeks embryonic life will not come to medical attention

Clinical spontaneous misscarriage and abortion

About 15% of clinically recognized pregnancies terminate in spontaneous abortion

About 50-60% of all first trimester spontaneous abortions are associated with the number or structure of the chromosomal complement

The earlier the embryonic age, the more likely the chromosomal complement will be

Frequency of Chromosome Abnormalities among Spontaneous Abortuses,

When Considered According to Gestational Age

Spontaneous Abortions

Gestation (Weeks) (% Chromosomally Abnormal

Induced abortion: currently 1/3 live births

Etiology of spontaneous abortion

Chromosomal abnormalities in greater than 50 %

Distribution of chromosome anomalies among spontaneous abortuses and Down's syndrome

Monosomy X (45, X) is the single most common chromosomal anomaly found among spontaneous abortuses

Maternal factors

Uterine

Anomalies

Myomas

Synechiae

b. Endocrine/metabolic

Diabetes

Thyroid

Vascular

Luteal phase

c. Infection

Mycoplasma

Viral