Serum myosin-binding protein c levels: a new marker for exclusion of preterm birth?

To evaluate whether there is a relationship between serum myosin-binding protein C (MyBP-C) levels measured in the first trimester and the timing of delivery, and, if a relationship is detected, the potential of this relationship in distinguishing between preterm and term labor.

This prospective case-control study was conducted with 701 pregnant women who applied to the Obstetrics Outpatient Clinic of Gaziosmanpaşa Training and Research Hospital in the first trimester, between 11 and 14 gestational weeks. MyBP-C serum samples from the first trimester were stored under appropriate conditions until the time of delivery. Of these pregnant women, 628 completed the study. According to the delivery time, the pregnant women were divided into two groups, as those who delivered prematurely before 37 weeks and those who gave birth at term. The case group comprised 45 women who gave birth prematurely, while 583 women gave birth at term. A control group was formed with 45 pregnant women of the same age, who were selected by randomization using a simple random sampling method from the 583 pregnant women. The MyBP-C levels were measured and compared from the first-trimester serum materials of both groups.

The MyBP-C levels of the preterm delivery group were significantly higher than those of the term delivery control group (4.51 ± 1.69 vs. 3.09 ± 1.44 pg/mL, respectively; p < 0.001). Receiver operating characteristic (ROC) curve analysis showed that the MyBP-C levels in the first trimester with a cut-off value of 4.76 ng/dL indicated women with preterm delivery with a sensitivity of 42.22% and specificity of 95.56% (AUC: 0.734, 95% CI: 0.630-0.822). The overall differential diagnosis performance of the MyBP-C level for preterm delivery was determined as 73.4% (p < 0.001). The MyBP-C levels were found to be significantly higher both in the early preterm group compared with the late preterm group (p < 0.001), and in those with premature rupture of membranes (PROM) compared with those without (p < 0.001).

The preterm delivery group exhibited high serum MyBP-C levels in the serum samples taken in the first trimester. First-trimester serum MyBP-C levels seem to be a simple and easy way to exclude preterm delivery risk in a significant manner. In addition, levels are significantly higher for early preterm compared with late preterm and early PROM compared with intact membranes.