Smith's Recognizable Patterns of Human Deformation

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KEY POINTS The direction and magnitude of forces affect the form of the developing fetus. Abnormal mechanical forces give rise to deformation in humans in much the same fashion as abnormal forces may deform a tree. The tissues of a…

KEY POINTS Fetal vascular disruption defects refer to structural defects that occur after a structure has formed normally, and they are usually limited to tissues within a defined area that are supplied by the affected blood vessels. Decreased blood flow…

KEY POINTS The underlying mechanism for most defects related to problems associated with failed first-trimester obstetric procedures is vascular disruption. With chorionic villus sampling, removal of villi may result in embryonic hypotension, hypoxia, endothelial damage, hemorrhage, and necrosis with tissue…

KEY POINTS Compression during early morphogenesis (the first trimester) can result in three types of defects: molded deformations, incomplete morphogenesis, and disruptions of morphogenesis. Experimental animal studies showed that early amniotic sac puncture caused defects similar to Pierre Robin sequence,…

KEY POINTS Ectopic pregnancy occurs when a fertilized ovum implants outside the uterus, most commonly in the fallopian tube. Risk factors for ectopic pregnancy include tubal damage, prior ectopic pregnancy, use of intrauterine devices, tubal sterilization, infertility, pelvic inflammatory disease,…

KEY POINTS Fetal movement is crucial for normal joint development, and lack of movement can lead to joint contractures. Prenatal diagnosis of fetal akinesia may reveal additional structural abnormalities such as cystic hygroma, increased nuchal translucency, and hydrops fetalis. Fetal…

KEY POINTS Amniotic fluid tends to decrease during the last trimester of pregnancy, and a serious deficiency can result in fetal constraint. Oligohydramnios may be caused by renal/urinary tract malformations or amniotic rupture, accompanied by constrictive amnion strands, which can…

KEY POINTS Various types of uterine malformations, such as bicornuate or myomatous uterus, can lead to small uterine cavity deformation, increasing the risk of fetal deformation and complications. Diagnostic procedures like hysterosalpingography, laparoscopy, and 3D ultrasonography are more accurate in…

KEY POINTS Factors contributing to face presentation include fetal anomalies, contracted pelvis, fetopelvic disproportion, or cord around the neck. Face presentation is more common in large infants (>4000 g), small infants (<2300 g), and cephalopelvic disproportion. Cesarean section is considered…