Getting pregnant when you have blocked fallopian tubes may seem impossible, but it can happen in rare cases. Blocked tubes (also called tubal occlusion) are one of the most common causes of infertility since they prevent the egg and sperm from meeting. However, there are a few ways that pregnancy can still occur with blocked fallopian tubes.
What causes blocked fallopian tubes?
The fallopian tubes are the pathways that carry eggs from the ovaries to the uterus. For pregnancy to happen, sperm must fertilize an egg while it’s traveling through the tube. Blocked tubes prevent this from occurring normally. Some causes of tubal blockage include:
- Pelvic inflammatory disease (PID) – PID is often caused by sexually transmitted infections like chlamydia and gonorrhea. It causes inflammation and scarring in the reproductive organs.
- Previous surgery – Such as a tubal ligation for sterilization purposes or removing an ectopic pregnancy.
- Endometriosis – Cells from the uterine lining can get stuck in the tubes and cause blockages.
- Congenital abnormalities – Some women are born with misshaped or missing tubes.
- Scarring from ruptured ovarian cysts or abdominal surgery.
How pregnancy is still possible
Even when both tubes are completely blocked, the following situations may make getting pregnant possible:
Tubal spasm
Sometimes fallopian tubes go through temporary spasms that make them impassable for sperm or eggs. These spasms may release and open the tubes for a short period of time. If timing is right, sperm might swim through just before or after ovulation.
Tubal openings on both sides
Complete tubal blockages are not always 100% closed off. Very small openings on either end of the tubes may exist. Sperm may swim through one opening, fertilize an egg, and the embryo can travel back the way it came to implant in the uterus.
Accessory tubal channels
While rare, some women have tiny extra tubes alongside their main fallopian tubes. Even if the main channels are blocked, sperm may pass through these accessory channels to reach an egg.
Ectopic pregnancy
When a fertilized egg gets stuck in a blocked fallopian tube it results in an ectopic pregnancy. This is dangerous for the mother and impossible to carry to term. But before it’s discovered and removed, the ectopic pregnancy may rupture and release the embryo. If this occurs close to the uterus, the embryo could re-implant in the uterine lining.
Difficulty verifying tubal status
Laparoscopy surgery is done to examine the fallopian tubes and see blockages. Sometimes dye is injected through the tubes to verify whether it spills out the other end. If spillage is seen, the tubes may be declared open and fine. However, the dye test can occasionally give false positive results. Blockages may exist higher up where dye can still spill over.
Recanalization
Rarely, a blocked fallopian tube may spontaneously open up again over time. This recanalization can occur after inflammation reduces or damage repairs itself. Scarring may break down to create a path for an egg or sperm to pass through.
Undetected hydrosalpinx
A hydrosalpinx is a fallopian tube blocked at one end and filled with fluid. The open end nearest the ovary may still collect an egg. If sperm enters through the open end, fertilization can occur. However, the embryo will be stuck and unable to reach the uterus.
When is pregnancy possible?
Getting pregnant with blocked tubes depends greatly on the extent and location of the blockage. Here are some scenarios where conception may occur:
- Only one tube is blocked – The open tube can function normally.
- Blockage is low on one or both tubes – Closer to the uterus allows more potential for sperm to pass through.
- Partial blockage – Some narrow openings exist.
- Intermittent spasms – Timed with ovulation the tubes open temporarily.
- Tubal openings revert from complete blockage.
- egg is fertilized in a hydrosalpinx then released.
When tubal disease is extensive or both ends of a tube are obstructed, the chances of pregnancy fall below 5%. But minor blockages may only reduce the monthly chance of conception down to 10-25%.
Risks of tubal pregnancy
Pregnancy with blocked fallopian tubes has serious risks including:
- Ectopic pregnancy – Over 95% of pregnancies with tubal infertility are ectopic. Rupture and blood loss are threats requiring emergency surgery.
- Miscarriage – Structural tube damage raises the changes of early miscarriage.
- Preterm delivery – Tubal abnormalities can trigger early or premature birth.
Because of heightened risks, those who know they have blocked tubes should seek urgent medical care at any signs of pregnancy. HCG levels should be monitored and early ultrasounds done to check for ectopic implantation.
Increasing chances of conception
If natural conception with blocked tubes is desired, here are some tips that may help:
- Tracking ovulation signs closely to optimize timing.
- Considering tubal surgery to repair blockages if hydrosalpinx or endometriosis related.
- Doing gentler conception methods like the sperm meets egg plan.
- Trying conception aids like fertility lubricants or softcups.
- Avoiding risky sexual positions that may force sperm up against blockages.
However, those with extensive bilateral blockages will still have poor odds of conception. IVF provides the best success rates in these cases by bypassing the tubes entirely.
When to seek fertility help
If you have blocked fallopian tubes, see a fertility specialist right away if:
- You are over 35 years old.
- Known blockages are present.
- You have had pelvic infections like PID.
- You have endometriosis.
- You have had abdominal/pelvic surgery.
Time is crucial when dealing with tubal problems. The longer you try, the lower your egg quantity and quality will get. Seeing a specialist quickly can help diagnose any tubal issues and start effective treatments sooner.
IVF success rates with tubal factor
In vitro fertilization (IVF) is the most successful treatment for infertility caused by blocked fallopian tubes. IVF bypasses the need for open tubes by fertilizing eggs with sperm in a lab dish. The embryos are then transferred directly into the uterus.
According to SART data, the average IVF success rates per embryo transfer with tubal factor infertility are:
| Age | Success Rate |
|---|---|
| Under 35 | 51.6% |
| 35-37 | 46.7% |
| 38-40 | 36.6% |
| Over 40 | 27.7% |
Success rates for IVF with tubal factor are close to the average rates for all infertility diagnoses combined. This shows that blocked tubes alone should not significantly lower IVF success if age-related egg quantity/quality is fine.
Surgery before IVF?
Whether tubal surgery should be done before IVF depends on the specifics of the blockages. Referral to a reproductive surgeon for evaluation is recommended.
Surgery may be advised if tubes are:
- Only partially blocked.
- Blocked at the lower end nearer the uterus.
- Blocked due to hydrosalpinx fluid.
- Blocked from scar tissue or adhesions.
However, surgery is not helpful if tubes are extensively damaged or completely blocked at both ends. The risks, costs, and recovery time also have to be weighed against simply moving forward with IVF.
Tubal removal before IVF
If hydrosalpinx fluid is present, the tube should be removed prior to IVF. Research shows this fluid can leak into the uterus and prevent implantation or cause miscarriage. Removal of the tube eliminates this risk and can improve IVF success.
Alternatives to IVF
For those who wish to conceive without IVF, alternatives may include:
- Tubal surgeries – Such as salpingostomy, tuboplasty, or reversals.
- Tubal flushing or catheterization – To unblock tubes.
- Falloposcopy – Inserting a camera into tubes to inspect and unblock them.
- GIFT/ZIFT – Putting sperm and eggs directly into the tubes or uterus.
- Adoption or using a gestational carrier.
However, pregnancy rates with these options are typically under 30% per procedure. Multiple attempts are often needed. Lengthy treatment also allows more damage to accumulate in aging eggs or tubes. So IVF still provides the best outcomes in most cases.
Takeaways
- Pregnancy with blocked fallopian tubes is rare but can happen through tubal spasms, tiny openings, or freak dysfunctions.
- Risks like ectopic pregnancy are high with tubal pregnancies.
- Mild blockages on one side only allow for better odds.
- IVF has high success rates for tubal factor infertility.
- Surgery may help clear some blockages before IVF.
Conclusion
Blocked fallopian tubes are a major cause of infertility but don’t rule out getting pregnant entirely. In very rare cases, pregnancy may occur due to intermittent tube openings, tiny passages, or abnormal dysfunctions. However, the risks of ectopic pregnancy or miscarriage are high. Mild tube defects can raise chances for natural conception. But for most, IVF provides safe, effective treatment with excellent success rates. Surgery may be done first in select cases if it could improve the chances of conception. Overall, seeing a fertility specialist right away for a full workup is important when dealing with potential tubal infertility.