A client uses nitrous oxide during labor. What should the nurse teach?

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.

Insulin is the primary pharmacological agent for managing gestational glycaemia when lifestyle modifications fail. It provides precise control of maternal blood sugar without interfering with fetal endocrine function. The molecular weight of insulin is too high to allow passive diffusion across the chorioamniotic membranes.

A. Insulin is cheaper: The cost of insulin and the required supplies for monitoring and injection is often significantly higher than oral medications. However, clinical choice is based on safety and efficacy rather than financial expenditure. Economics do not dictate the medical preference for insulin in pregnancy.

B. Insulin crosses the placenta easily: If insulin crossed the placenta, it would cause severe fetal hypoglycemia and hyperinsulinemia, leading to macrosomia and birth defects. The safety of insulin relies specifically on the fact that it remains within the maternal compartment. It does not enter fetal circulation.

C. Oral agents are ineffective: While some oral agents like metformin can lower blood sugar, they cross the placenta and their long-term effects on the fetus are still under investigation. Insulin remains the most potent and titratable option for achieving target glucose levels. It is the gold standard for clinical reliability.

D. Insulin does not cross the placenta: This characteristic ensures that the medication lowers maternal glucose without directly affecting the fetal pancreas. It prevents the risk of iatrogenic neonatal hypoglycemia while treating the mother's diabetes. This makes it the safest choice for the developing fetus.