A client asks how her due date is calculated. Which is correct?

Sexually transmitted infections (STIs) often trigger pelvic inflammatory disease (PID), leading to irreversible scarring of the reproductive tract. This anatomical damage frequently involves the fallopian tubes, causing tubal factor infertility or ectopic pregnancy. Screening allows for early antibiotic intervention to prevent long-term sequelae.

A. "Untreated STIs can cause infertility.": Pathogens like Chlamydia trachomatis can cause subclinical infections that lead to tubal occlusion. Chronic inflammation destroys the delicate ciliary epithelium required for ovum transport. Screening and treatment are essential preventative measures for preserving future reproductive capacity.

B. "It replaces vaccines.": STI screening is a diagnostic tool and does not provide immunity or replace immunizations like the HPV vaccine. Screening detects existing infections, while vaccines prevent them from occurring. Both are complementary components of preventative medicine but serve different functions.

C. "It prevents menstruation.": STIs do not typically interfere with the hormonal regulation of the menstrual cycle. While they may cause intermenstrual spotting or abnormal discharge, they do not cause amenorrhea. Menstruation is governed by the ovarian-pituitary axis, not by the presence of pathogens.

D. "It improves fertility.": Screening itself does not "improve" baseline fertility but rather protects existing fertility from degradation by infection. It is a defensive health measure. High fertility depends on gamete quality and uterine receptivity, which are not directly enhanced by a test.

Preterm labor is defined as the presence of regular uterine contractions that result in progressive cervical effacement or dilation before 37 weeks. While subjective symptoms like back pain are common, objective cervical change is the definitive diagnostic requirement. Identifying true labor early allows for the administration of tocolytics and steroids.

A. Mild abdominal discomfort: Vague abdominal pain or "tightening" can often be attributed to Braxton Hicks contractions or round ligament pain. Without associated changes to the cervix, discomfort alone does not constitute labor. These sensations are often non-productive and resolve with hydration.

B. Cervical change with regular contractions: The hallmark of true labor is the mechanical opening of the cervix (dilation) and thinning (effacement) in response to uterine activity. This indicates that the lower uterine segment is actively preparing for delivery. It is the most reliable indicator of imminent preterm birth.

C. Increased fetal movement: Normal fetal activity is a sign of well-being and is not a symptom of labor. In fact, maternal perception of movement may sometimes decrease during intense labor as the fetus descends. Movement does not influence cervical ripening or uterine contractility.

D. Irregular contractions without pain: These are characteristic of false labor or "pre-labor" warming. If the contractions do not follow a rhythmic pattern and fail to change the cervix, they are considered clinically insignificant for the diagnosis of labor. They lack the expulsive force of true labor.