A 28-year-old woman presents to her obstetrician for preconception counseling. She has been trying to conceive with her partner for the past 6 months without success. She reports regular menstrual cycles with a duration of 28 days. Past medical history is unremarkable, and she does not take any medications. Vital signs are within normal limits. Physical examination is unremarkable. She asks her physician about the timing and location of fertilization if it were to occur.
A) Ampulla of the fallopian tube
Fertilization typically occurs in the ampulla of the fallopian tube when a spermatozoa meet the secondary oocyte after ovulation.
Answer choice B: Cervix, is incorrect. Fertilization does not occur in the cervix; it primarily serves as a passage for sperm to enter the uterus.
Answer choice C: Endometrium, is incorrect. The endometrium is the inner lining of the uterus where implantation of the fertilized ovum occurs, but fertilization itself does not occur here.
Answer choice D: Ovary, is incorrect. While ovulation occurs in the ovary, fertilization does not occur here.
Answer choice E: Uterine fundus, is incorrect. The uterine fundus is the top portion of the uterus, and fertilization does not occur here.
Key Learning Point
Fertilization occurs when a sperm enters the egg, usually in the ampulla of the fallopian tube. This is considered embryologic day 0. The gestational age is embryologic age + 14 days.
