Click here to view next page of this article
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:
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