The drug of choice for treatment of gonorrhea is:

Choice A reason:

Nagele's rule for calculating the estimated date of confinement (EDC) involves subtracting 3 months from the first day of the last menstrual period and adding 7 days. For February 13th, subtracting 3 months gives us November 13th, and adding 7 days gives us November 20th. This is the most accurate calculation for the estimated date of confinement.

Choice B reason:

This choice is not accurate according to Nagele's rule. Adding 7 days to November 13th would give November 20th, not November 27th.

Choice reason:

This choice is not accurate according to Nagele's rule. Adding 7 days to November 13th would give November 20th, not November 21st.

Choice D reason:

This choice is not accurate according to Nagele's rule. Subtracting 3 months from February 13th would give November 13th, not November 14th.

Choice A reason: Normal weight women should gain 11.5 to 16 kg during pregnancy, according to the Institute of Medicine (IOM) guidelines. This is based on the body mass index (BMI) of 18.5 to 24.9 before pregnancy.

Choice B reason: Underweight women should gain 12.5 to 18 kg during pregnancy, according to the IOM guidelines. This is based on the BMI of less than 18.5 before pregnancy. Underweight women are at risk of having low birth weight infants, so they need to gain more weight to support fetal growth and development.

Choice C reason: Adolescents are encouraged to strive for weight gains at the upper end of the recommended scale, according to the IOM guidelines. This is because adolescents are still growing themselves and need extra nutrients and calories to meet their own needs and those of the fetus.

Choice D reason: In twin gestations, the weight gain recommended for a single fetus pregnancy should not be simply doubled. The IOM guidelines suggest that women with twin gestations should gain 16.5 to 24.5 kg if they have a normal weight before pregnancy, 14 to 22.5 kg if they are overweight, and 11 to 19 kg if they are obese.

Choice E reason: Obese women should gain at least 7 to 11.5 kg during pregnancy, according to the IOM guidelines. This is based on the BMI of 30 or more before pregnancy. Obese women are at risk of having complications such as gestational diabetes, preeclampsia, and cesarean delivery, so they need to limit their weight gain to avoid further complications.