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:

The correct answer is d. Amenorrhea.

Choice A: Chadwick’s sign is a non-specific, early sign of pregnancy that is typically characterized by a bluish discoloration of the cervix, vagina, and vulva. The Chadwick sign can typically be observed as early as six to eight weeks after conception, and commonly disappears shortly after birth. However, it’s not a definitive indication of pregnancy, and the absence of it on physical exam does not exclude a potential pregnancy.

Choice B: Hegar’s sign is a non-specific indication of pregnancy that is characterized by the compressibility and softening of the cervical isthmus (i.e., the portion of the cervix between the uterus and the vaginal portion of the cervix). It typically presents between the fourth and sixth week of pregnancy and may be present until the 12th week of pregnancy. However, the Hegar sign is not a definitive indication of pregnancy, and the absence of it does not exclude a potential pregnancy.

Choice C: A positive pregnancy test By 10 weeks, a home pregnancy test would almost certainly show a positive result if the woman is pregnant. This is because the hormone human chorionic gonadotropin (hCG), which is produced by the placenta after implantation of the embryo into the uterine wall, would be present in high enough levels to be detected by the test. However, a positive pregnancy test is not a presumptive sign of pregnancy, but rather a probable one.

Choice D: Amenorrhea, or the absence of menstrual periods, is often considered the most presumptive sign of pregnancy. This is because it’s one of the first noticeable signs of pregnancy for many women. By 10 weeks of gestation, the woman would likely have missed two menstrual periods if she usually has regular cycles. However, while amenorrhea is a common early sign of pregnancy, it can also be caused by various other conditions or factors such as stress, significant weight loss or gain, or certain medical conditions. Therefore, a missed period should be followed up with a pregnancy test to confirm pregnancy.

Choice A: February 6-7 is incorrect. This is too late for the woman's fertile period, which occurs around the time of ovulation. Ovulation usually happens about 14 days before the next period starts, which would be around January 22 for a 28-day cycle¹.

Choice B: January 22-23 is incorrect. This is too close to the woman's next period, which is expected to start around February 5 for a 28-day cycle. The chances of getting pregnant are very low at this time, as the egg only survives for about 24 hours after ovulation¹.

Choice C: January 30-31 is incorrect. This is after the woman's fertile period, which ends about a day after ovulation. Ovulation usually happens about 14 days before the next period starts, which would be around January 22 for a 28-day cycle¹.

Choice D: January 14-15 is correct. This is within the woman's fertile period, which begins about 5 days before ovulation and ends about a day after ovulation. Ovulation usually happens about 14 days before the next period starts, which would be around January 22 for a 28-day cycle¹. Sperm can survive in the female reproductive tract for up to 5 days, so having sex during this time can increase the chance of conception¹.