In vitro fertilization-embryo transfer (IVF-ET) is a common approach for women with blocked fallopian tubes or unexplained infertility and for men with very low sperm counts. A husband and wife have arrived for their preprocedural interview. The husband asks the nurse to explain what the procedure entails. The nurse's most appropriate response 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: A fetal heartbeat auscultated with a Doppler or a fetoscope is a positive sign of pregnancy, as it confirms the presence of a living fetus in the uterus. A Doppler is an electronic device that uses sound waves to detect the fetal heart rate, while a fetoscope is a stethoscope-like instrument that amplifies the fetal heart sounds. The fetal heartbeat can be heard as early as 10 to 12 weeks of gestation with a Doppler and 18 to 20 weeks of gestation with a fetoscope.

Choice B reason: Quickening is the first perception of fetal movement by the pregnant woman, usually felt between 16 and 20 weeks of gestation for first-time mothers and 13 to 16 weeks of gestation for experienced mothers. However, quickening is not a positive sign of pregnancy, as it can be subjective and mistaken for other sensations, such as gas, hunger, or muscle spasms².

Choice C reason: Morning sickness is a common symptom of pregnancy that involves nausea and vomiting, usually in the first trimester. However, morning sickness is not a positive sign of pregnancy, as it can be caused by other factors, such as food poisoning, stress, or medication.

Choice D reason: A positive pregnancy test is a probable sign of pregnancy, not a positive sign. A pregnancy test detects the presence of human chorionic gonadotropin (hCG), a hormone produced by the placenta, in the urine or blood of the woman. However, a positive pregnancy test does not guarantee a viable pregnancy, as it can be influenced by the timing, the quality, or the interpretation of the test. A positive pregnancy test can also occur in cases of ectopic pregnancy, molar pregnancy, or miscarriage.