The Impact of Conception Method, Chorionicity, Amnionicity, Fetal Growth Types, and Birth Order on the Postnatal Status of Twins Born Vaginally and by Cesarean Section: A Retrospective Analysis of Data from a University Centre of Obstetrics and Gynecology (1990-2017).

Background/Objectives: Twin pregnancies have long been of interest to the scientific community. Particular attention has been paid to factors influencing the postnatal condition of newborns. However, findings related to this issue, obtained in various centres, remain inconclusive. Methods: Data from 845 pairs of twins born between 1990 and 2017 at the University Centre of Obstetrics and Gynecology in the Wroclaw Medical University were analyzed. The postnatal condition was assessed based on the Apgar score at the 5th minute after birth. The Apgar scores were categorized into three groups: 8-10 indicated a good condition, 4-7 moderate, and 0-3 poor. Pregnancies with unknown chorionicity and amnionicity, monochorionic and monoamniotic pregnancies, still births, and cases with fetal defects were excluded from the study (126 cases). Finally, data of 719 pairs of twins were included. Results: Twins with a birth weight difference of less than 15% were more likely to receive a good Apgar score compared to those with a greater weight discrepancy (p < 0.001). The second-born twin was more likely to receive a good Apgar score compared to the first-born (p < 0.001). A higher proportion of twins delivered by cesarean section received a good Apgar score compared to those delivered vaginally (p < 0.001). The method of conception, chorionicity, amnionicity and being the smaller or bigger twin in the pair did not significantly affect the perinatal outcomes. Conclusions: Delivery method, birth order, and weight discrepancy play a key role in postnatal condition of twins, highlighting the importance of understanding these factors to optimize the management of twin pregnancies.