The most common site of implantation of fertilized ovum is?
A. Posterior wall of uterus
B. Fundus of uterus
C. Anterior wall of uterus
D. Fallopian tube
Correct Answer: A. Posterior wall of uterus
Explanation
The most common site of implantation of the fertilized ovum is:
👉 Posterior wall of the uterus near the fundus
Explanation
After fertilization in the ampulla of the fallopian tube, the zygote divides and reaches the uterine cavity as a blastocyst in about 5–6 days. Implantation normally occurs in the uterus where the endometrium is thick and well-vascularized.
Why the posterior wall near the fundus?
- It has rich blood supply
- Endometrium here is thick and receptive
- Provides optimal support for placental development
- Less exposure to pressure compared to the lower uterine segment
Explanation of other possible sites
- Anterior wall of uterus – A normal site but less common than posterior wall
- Fundus of uterus – Implantation commonly occurs near the fundus, especially on the posterior wall
- Fallopian tube – Abnormal implantation → ectopic pregnancy (most commonly in the ampulla)
Final Answer
✅ Posterior wall of the uterus near the fundus
Other Options Details
These options describe possible sites of implantation of the fertilized ovum in pregnancy. I’ll explain each option clearly and also indicate their significance.
A. Posterior wall of uterus
- This is the most common and normal site of implantation.
- Implantation usually occurs in the upper part of the uterus, closer to the fundus.
- It provides good blood supply, allowing normal placental development.
- Clinically favorable and safe.
B. Fundus of uterus
- The fundus is the uppermost part of the uterus.
- Implantation here is ideal and normal.
- Ensures:
- Better placental attachment
- Reduced risk of placenta previa
- Considered the best site for implantation.
C. Anterior wall of uterus
- Implantation on the front wall of the uterus.
- Can be normal, but slightly less common than posterior wall implantation.
- Usually causes no complications, though fetal movements may be felt earlier.
- Generally clinically acceptable.
D. Fallopian tube
- Implantation here is abnormal.
- This leads to ectopic (tubal) pregnancy.
- Dangerous condition because:
- Tube cannot expand like uterus
- May rupture causing severe internal bleeding
- Requires urgent medical treatment.
Summary Table
Option Site Normal / Abnormal A Posterior uterine wall Normal (most common) B Fundus of uterus Normal (best site) C Anterior uterine wall Normal D Fallopian tube Abnormal (ectopic pregnancy)
✅ Most correct and preferred site of implantation:
Fundus or posterior wall of the uterus
I hope that you liked this article.
Thanks!! 🙏 😊
Writer: Vandita Singh, Lucknow (GS India Nursing Group