To investigate changes in coagulation during twin pregnancies. Methods: A total of 108 women with twin pregnancies and 442 women with singleton pregnancies were recruited. Coagulation tests, including fibrinogen (Fib), activated partial thromboplastin time (APTT), prothrombin time (PT) and thrombin time (TT), were performed during the course of the pregnancy. The level of fibrinogen gradually increased during singleton pregnancies, while the APTT and PT levels showed a decreasing trend with increasing gestational weeks. In twin pregnancies, the changes in PT and TT were similar, but other parameters displayed a different trend. Fibrinogen showed no significant difference between the second and third trimesters, while APTT showed an increasing trend from the second trimester to the third trimester. Compared with singleton pregnancies, the level of fibrinogen was higher in women pregnant with twins. APTT was longer in women pregnant with twins than in women with singleton pregnancies in the third trimester. PT was shorter in women pregnant with twins than in women with singleton pregnancies in the first and third trimesters. TT was shorter in women pregnant with twins than in women with singleton pregnancies in the first and second trimesters. Through this retrospective longitudinal analysis, this study presents the main coagulation parameter changes in singleton and twin pregnancies and confirms that coagulation is more enhanced in twin pregnancies than in singleton pregnancies.
Keywords: coagulation; pregnancy; singleton; twin.