Conception & Early Pregnancy Study Sheet
Key Steps in Conception
1. Ovulation – Release of a mature ovum into the fallopian tube.
2. Fertilization – Occurs in the outer third of the fallopian tube (ampulla). One sperm penetrates the
ovum.
3. Cell Division – Zygote → morula → blastocyst.
4. Implantation – Blastocyst implants in the anterior or posterior fundal region of the uterus (6–10 days
after fertilization).
Developmental Periods
Period Time Frame Key Features
Preembryonic First 2 weeks Fertilization to implantation; nutrition from uterine secretions
Embryonic Weeks 3–8 Organogenesis; most critical for teratogens
Fetal Week 9 to birth Growth and maturation of organs
Hormonal Support
Corpus luteum produces progesterone and estrogen until placenta takes over (~10–12 weeks).
Quick Facts & Memory Tip
• Fertilization → outer third of fallopian tube.
• Implantation → fundal region of uterus.
• Only one sperm penetrates ovum.
• Preembryonic = first 2 weeks.
• Placenta takes over hormone production after first trimester.
Memory Tip: F-I-P-O-C = Fertilization, Implantation, Preembryonic (2 weeks), One sperm, Corpus
luteum.
Practice Questions
1. Where does fertilization occur? (Answer: Outer third of fallopian tube)
2. How long is the preembryonic period? (Answer: First 2 weeks)
3. What structure produces hormones before the placenta takes over? (Answer: Corpus luteum)
