What is one potential risk of maternal tobacco use during pregnancy?

Tobacco use during pregnancy is associated with several adverse outcomes, one of which is the risk of spontaneous abortion, also known as miscarriage. Smoking can lead to changes in the uterine environment, impacting placental implantation and function, which can increase the likelihood of pregnancy loss in the first trimester and beyond. It is also known to affect hormone levels that are crucial for sustaining a pregnancy.

This risk arises because nicotine and other harmful substances in tobacco can damage the developing fetus and the placenta. Additionally, maternal smoking can lead to increased levels of carbon monoxide, which reduces the oxygen available to the fetus, contributing to complications, including spontaneous abortion.

Other options present outcomes that generally do not align with the established research surrounding tobacco use in pregnancy. For instance, maternal tobacco use is usually linked to reduced birth weights rather than increased ones, making the association to increased birth weight inaccurate. Similarly, decreased blood pressure is not a common or expected direct outcome of maternal smoking, nor does it correlate particularly to delayed labor in the context of pregnancy complications commonly associated with tobacco use.