First trimester loss
Many women have first trimester losses. The most common reasons include poor implantation, chromosomal abnormalities, uterine abnormalities, autoimmune disorders, some maternal medical conditions.
Second Trimester loss
Second trimester losses are not common but when they do occur are usually related to cervical insufficiency, uterine abnormalities, fetal problems such as birth defects or chromosomal problems, lagging fetal growth, placental problems, unexplained stillbirths.
Third Trimester loss
Third trimester losses are stillbirths. Sometimes there is an explanation, other times they may be unexplained. Some maternal medical conditions such as diabetes, and high blood pressure may increase the risk, other times there may be fetal or placental problems that occur.
A thorough evaluation may help in identifying a cause. The evaluation can be comprehensive and usually includes evaluation for maternal medical problems such as diabetes and thyroid disease, hormonal imbalance, in some case an evaluation for both acquired and genetic clotting disorders, maternal and paternal evaluation for chromosome evaluations, some mothers may have uterine abnormalities that would need to be evaluated by ultrasound or even 3D vaginal ultrasound.