Objective. To establish clinical criteria for the development of undifferentiated connective tissue dysplasia (UCTD) in the study of the fetoplacental unit for antenatal prediction, by regarding a gender approach and estimating their prognostic importance. Subject and methods. 610 pregnant women aged 20 to 37 years with UCTD were examined; their medical and prenatal records and childbirth and neonatal developmental histories were analyzed. A control group consisted of 100 pregnant women without signs of UCTD. All the pregnant women underwent questionnaire survey, clinical laboratory, and instrumental examinations. To identify the antenatal signs of UCTD, ultrasonographic findings were analyzed in 140 pregnant women with fetal malformations versus 55 women with physiological pregnancy. The daily urine level of magnesium ions was determined during early pregnancy. Results. Five fetoplacental unit factors that are significantly correlated with the signs of UCTD in the fetus have been identified. In the aggregate, these 5 factors are responsible for 73.7% dispersion in the analyzed statistical sample. Factors that are of the highest diagnostic significance characterize the functional state of the placenta and umbilical cord vessels: marginal placental presentation, placental abnormalities, uterine artery tortuosity, reduced uteroplancental and fetoplacental blood flows, and cord entanglement. Of diagnostic importance are the following fetometric parameters: an unstable, oblique, transverse lie of the fetus, pelvic presentation, female sex, and fetal malformations. Lower daily urine magnesium ion levels were found in women with UCTD in early pregnancy. Conclusion. The developed prenatal screening will be able to make up groups at risk for fetal and neonatal connective tissue disorders among pregnant women, to timely implement preventive measures including magnesium intake, to provide rational delivery and postnatal screening, and to define a plan of necessary rehabilitation measures.