Which condition is associated with the risk of preterm labor?

The association of multiple pregnancies with the risk of preterm labor is well-documented. When a woman is carrying more than one fetus, the uterus is distended more than it typically would be in a singleton pregnancy. This increased stretching and pressure can stimulate contractions and lead to preterm labor.

Multiple pregnancies are also often associated with other risks such as early rupture of membranes and cervical incompetence, all of which contribute to delivering before the full-term gestation period. The increased demands on the mother's body, such as higher levels of hormone production and nutritional needs, can further complicate the pregnancy, leading to a greater likelihood of complications, including preterm labor.

In contrast, while high blood pressure and gestational hypertension can create risks during pregnancy, they are not as directly linked to preterm labor as the condition of carrying multiple fetuses. Low fetal movement can indicate problems, but it is not a direct risk factor for preterm labor. Understanding these distinctions helps in recognizing the importance of monitoring multiple pregnancies closely for the health of both the mother and the babies.