What complications can untreated chlamydial infections cause during pregnancy?

The complications associated with untreated chlamydial infections during pregnancy are significant, and option B correctly highlights the serious risks involved. Chlamydia, when left untreated, can lead to a variety of adverse outcomes including preterm labor, premature rupture of membranes, and low birth weight.

Premature rupture of membranes refers to the breaking of the amniotic sac before labor begins, which can increase the risk of preterm labor and infections. Additionally, low birth weight is a condition where the baby is born weighing less than 5 pounds, 8 ounces. This can lead to further complications for the infant, including developmental delays and increased vulnerability to infections.

The other options do not accurately reflect the established risks associated with untreated chlamydial infections. Increased maternal weight gain does not correlate with chlamydia, and high blood pressure in the mother is typically associated with other conditions rather than chlamydia specifically. Lastly, improved fetal growth contradicts the known complications of untreated infections, as these infections do not enhance fetal development or health. Instead, they pose risks that can hinder optimal pregnancy outcomes.