Which factor is associated with increased risk of prematurity?

Multiple gestation is indeed a significant factor associated with an increased risk of prematurity. When a pregnancy involves more than one fetus, such as twins or triplets, the likelihood of preterm labor and delivery is heightened. This is largely because the uterus is under greater stress due to the increased number of developing fetuses. Each additional fetus requires more space and resources, which can lead to complications and a greater risk of premature birth. Furthermore, multiple gestations often result in increased maternal health challenges, such as preeclampsia and gestational diabetes, that can also contribute to premature delivery.

In contrast, full-term birth history, lack of cervical surgeries, and optimal maternal nutrition are generally associated with a lower risk of prematurity. A history of full-term births typically suggests that a woman has successfully carried previous pregnancies to term, which may indicate a lower predisposition for issues leading to preterm labor. Lack of cervical surgeries implies a healthy cervix, which is essential for maintaining a pregnancy. Optimal maternal nutrition supports fetal growth and development, contributing positively to the chances of reaching term. Thus, the first option stands out as the correct answer due to its strong association with the increased risk of delivering prematurely.