Differences in physiological indicators between twin and singleton pregnancy.

OBJECTIVE

It has been widely reported that there are physiological differences between twin and singleton pregnancies, as evidenced by physiological indicators examined during prenatal period. However, not all physiological indicators have been evaluated. Physiological indicators of twin pregnancies still refer to the standards of single pregnancies and lack precise variation intervals. Therefore, our study compared and analyzed the differences in physiological indicators between twin and singleton pregnancies.

METHODS

Retrospective cohort data of deliveries at Peking University Third Hospital from January 1, 2012, to February 8, 2021, were utilized. Information of pregnant women, including maternal characteristics, 49 physiological indicators examined during four periods (postpartum, first, second, and third trimester), and pregnancy complications, was extracted from medical records. Mann-Whitney test and multiple linear regressions were conducted to evaluate the differences in physiological indicators between twin and singleton pregnancies and to demonstrate their variation trend throughout gestation.

RESULTS

A total of 40 746 cases were included (38 320 singleton pregnancy cases and 2426 twin pregnancy cases). In twin pregnancies, 16 indicators related to red blood cells, platelets, coagulation function, protein, creatinine, and blood lipids exhibited distinctions compared to singleton pregnancies throughout gestation. The results remained stable regardless of maternal complications.

CONCLUSION

Twin and singleton pregnancies are in distinct physiological conditions. It is of great necessity to establish specific reference intervals for twin pregnancies. Further study is needed to investigate the impact of physiological indicators on predicting adverse outcomes in twin pregnancies.