time it takes for sperm to penetrate egg?

[gizmo77]

once your egg pops out, obviously there is only 12-24 hrs for sperm to locate and fertilize before egg dies...but how long does it take for sperm to actually find and fertilize an egg? or just fertilize?

[Hobbermittens]

I wonder this too. Thanks for asking! I will keep watching this thread for the answer.....

[rainbowflower]

it depends if the sperm is already there waiting or not. I read somewhere ages ago it can take less than an hour if so... but if it's a "fresh deposit" the sperm would need to capacitate before it can penetrate the egg and I don't know how long that takes

[nuthinbutpink]

Check out this-

http://www.embryology.ch/anglais/dbe...ung/weg03.html

Take a look at the 2 pics-
Fig. 29, Fig. 30
These are monitor screen images from an instrument which records the movement paths of the sperm cells heads (white points) during a certain time span and displays them with a green line. Before capacitation the majority of the lines are straight. After capacitation almost all the sperm cells have now gone over to swinging their heads strongly as indicated by the jagged lines.

Might explain why those that choose to use the microscope see some straight line sperm and some that appear to be moving in circles!

Capacitation is the change in the sperm head membrane that prepares it for fusion with the egg membrane. Sperm have to undergo capacitation in the female reproductive tract before they are able to fertilize the egg. Capacitation is facilitated by the cervical mucus, and it usually takes several hours after ejaculation before the sperm can fertilize the egg. Sperm that reach the egg within minutes after ejaculation did not have enough time to undergo capacitation, and are less likely to be able to fertilize the egg.

The above might explain why it takes you guys TTC a girl longer to get pregnant if there is no cervical mucus to help out the sperm(there is always some and it doesn't take much!).

[gizmo77]

i guess i wanted to know a) how long does it take for a sperm to travel to our tubes and b) ho wlong does it take for one sperm to finally fertilize/fuse with the egg (for sperm that was waiting there for an egg).

thats interesting reading nbp. esply the part about if the sperm gets there too fast and no time to capacitate. so technically, it IS best for both girl and boy sways to DTD BEFORE ovulation. if you do it right at ovulation, theres a chance the sperm wont have enough time to capacitate and fuse....

[nuthinbutpink]

Fast swimming sperm, 30 minutes. They can live 48-72 hours though so it can take that long.

Fertilization takes 24 hours.

[rainbowflower]

gizmo - yep, another reason why O+12 is even more risky especially if your egg doesn't quite last the 24hrs as many don't

[atomic sagebrush]

Thanks guys, great answers as always. I really don't have a lot to add to this thread other than that I've read that the fastest sperm are not only uncapacitated, but usually dead on arrival anyway (they have nothing left to fertilize the egg because they swim so fast) and that the majority of sperm are actually brought to the egg by the currents of EWCM and not by the action of the sperm swimming. The sperm do swim, but it's more to get past obstacles and to make it from the VJ into the cervix.

I have always believed that of all the people on the planet, virtually all were conceived from sperm already there and waiting for the egg in advance. EVERYTHING about the design of the female repro tract points to this being a truth. That's why I am not a huge fan of either the traditional "one shot at O" timing for boys and O+12, because I think it hinders people from getting pg.

[gizmo77]

this is great info. i was wondering then tho, in couples diagnosed with "unexplained infertility" what do you guys think is the problem? too fast sperm not capicitating? so im talking about a woman with healthy eggs who ovulates every month and a man with a high amount of sperm with good mobility andmotility mortality (isnt that what "unexxplained fertility" is?) everything IS right but it just really isnt enough. the answers ive come up with are hostile environment (repro tract is just denying everything foreign, hostile uterus, same concept, or dna's dont match up (genetic imbalances?).

[nuthinbutpink]

How do you know she has healthy eggs? Genetic issues, uterus issues, timing, bad sperm for sure to name a few reasons.