What is the minimum volume of sperma required to get pregnant?

Factual Questions
1

Recently I read an article in which a gynecologist stated that a ‘‘drop of sperma is enough to get pregnant’’, so ‘‘interrupted sex’’ method of contraception is like a ‘‘Russian roulette’’. She said that there is a million of spermatozoids in a drop of sperma.

As I was taught in Pharmacology, 1 mL of water contains 20 drops. I presume the same is approximately correct for sperma. So I pretty much doubt that a drop of sperma is enough to get pregnant.

Even more I doubt in that for the reason, that in a lecture my Embryology professor said that one portion of ejaculate contains, if I’m not mistaken (that was two years ago), 30 millions of spermatozoids. And one portion is far more than a drop or a mililiter. But what I remember exactly, is that she said that **although only one spermatozoid **(sometimes two or few) fertilizes the ovocyte, the capacity of one spermatozoid for getting through the coats and membrane of the egg is not sufficient and other spermatozoids are required for their enzymes to help dissolving the coats. Besides, as the fertilization takes place in Fallopian tube, it is quite a long way from the vagina for the spermatozoid to travel. And even like that wasn’t a problem, 70 percent of spermatozoids should be active with the minimum speed of 2-3 mm per minute in the presence of cervical and vaginal secretion.

So my question is: is a drop of sperma really enough for a woman to get pregnant or does it require more?

And I also have an additional question. **I heard from another gynecologist, that it is not possible to get pregnant during the first 12 days after menses. **I do understand that ovulation time may vary every month, but anyway: what do you think?

Any physicians? Biologists?

Please, speak out!

Thanks in advance!

2

The only requirement is that a single swimmer make his way to and fertilize an egg. Unlikely, yes, but that’s what’s “required.” I don’t know the statistics on how many sperm cells it would take to ensure a given confidence level of no fertilization, but anything less than total abstention from sex introduces some chance of pregnancy.

My personal level of risk tolerance is such that I use a condom as the only method of birth control. I’m married & monogamous.

3

The periods of viability of sperm, the exact times of ovulation, and the interactions of a host of unpredictable factors make the twelve day fertile period a very rough estimate. One sperm cell is both the minimum, and the maximum necessary to fertilize an ovum.

There is a well known technical term for people who rely on the Rhythm Method. They are referred to as parents.

Tris

4

12 days is an arbitrary number and mostly wrong.

Cycles are measured from the first day of the bleed.

Ovulation varies from woman to woman but can be anywhere from a week to several weeks after the cycle starts. There is never a guaranteed infertility time frame for women. Some are on a very reliable cycle but there is always a chance of a odd firing off from an ovary.

Pregnancy can occur from intercourse a day or two prior to ovulation up to several days after.

If you’re trying to get pregnant, have sex every day for two weeks, starting after menses stops. With a bit more study and knowing when the woman regularly ovulates you can narrow than down to 5 days.

If you don’t want to get pregnant, but are still gonna have sex, - use a condom.

5

Isn’t there sometimes a slightly increase in body temperature when the most fertile moment approaches?

Hey, I have a brilliant idea! The one who writes the best reply will get the OP’s child named after him/her!

6

Pan1, I’m a male, all right? :slight_smile:

And this is just a theoretical, NOT a personal question. I use a condom either, JerseyFrank.

7

No, not really. Even during in vitro fertilization you have to have plenty of those. As I mentioned in the question post:

The spermatozoids are like knights-intruders and the egg is like a castle or a fortress. All the knights are needed for ‘‘braking in’’, but only one gets the princess.

8

Sperma?

9

Oh, sorry. My English isn’t perfect. I meant ‘‘sperm’’ or ‘‘semen’’

10

It only takes a few sperm reaching the egg to get pregnant (I’ve seen several videos of the moment of conception, and it seems to be 5-15 sperm that get there first, and one is accepted), so a droplet of semen carrying a million sperm is ‘enough’. The more semen, the higher the chances I suppose, but a tiny bit is surely sufficient. I know plenty of women who have gotten pregnant from just a bit.

According to a recent study published in Contraception magazine, timely withdrawel is 2% less effective than proper condom use at preventing pregnancy. It has been proven there is no sperm present in pre-ejaculate fluid - although if the man hasn’t urinated since the last time he came, there could be a few.

http://www.nytimes.com/2009/07/21/health/21cond.html

I’ve been using withdrawal as my sole method of ‘BC’ for 4 years and have never been pregnant. I would not use it if I was less comfortable with the idea of an unplanned pregnancy, though.

As for the other question - that gyn is nuts. I usually ovulate 14-15 days after the first day of my last period, and earlier ovulation is possible for me and routine in other women. Sperm can live up to 5 days in the proper conditions, so that would put me right the in the danger zone. 24 hours after ovulation has occurred is when you are safe. But most women do not know when they ovulate.

11

Out of curiosity, how do you know?

12

Here’s an answer I got outside this Message board:

13

I recall reading that there is some evidence that the presence of multiple sperm cells and the pH of the seminal fluid plays a role in the receptivity of the ovum to fertilization. So while it’s technically true that it takes only one sperm(-atozoön) to impregnate, the presence of multiple cells and the fluid in which they are ejaculated also plays a role.

14

EXACTLY! That’s juts what my professor said

15

Great, how’d you like go through life named Triskadecamus, The Piranha Brothers, rhubarbarin, Thudlow Boink, or Polycarp?

(NOTE: This response is just based on the user names that would make bad choices for real life names and is not meant to be seen as poking fun at the user names, or to suggest that their reply would be the potential “best”.)

16

.

You’re thinking basal body temperature, which rises AFTER ovulation. If you’re trying to get pregnant, and wait to have sex until after you’re temp rises, you’re too late. It’s used to confirm ovulation, not predict it.

Movies get this (among other things) wrong. Understanding your bbt means taking your temperature every morning, at about the same time, without talking or getting out of bed. So when you see movies where women are runing around with thermometers at 3 in the afternoon yelling “I’m ovulating!”, they’re doing it totally wrong.

17

I think rhubarbarin is a great name :slight_smile:

18

I’m trying to get pregnant and am having trouble, so I really, really read up on this stuff.

I’ll answer the ones I know for sure: Temperature rises and the 12 days past period question.

If a woman is charting her temperature (and the temperature must be taken upon waking, before getting out of bed, at the same time every morning, after a minimum of three full hours of sleep.), and she is ovulating, she will see a slight temperature rise the day following ovulation. This is because following ovulation, your body starts producting progesterone in anticipation of a pregnancy, and progesterone raises your temp. The rise in in the hundreths of a temp point, so you use a thermometer that reads to two decimal points. The temperature stays elevated until the woman (not pregnant) gets her period and the temp drops. The cycle begins again.

This method of tracking ovulation is only usefull after the fact. You only see the rise after you ovulate, so using it as a method of birth control is useless unless you track for a few months to determine your average fertile period. Same goes for trying to get pregnant - you track for a while, determine your fertile period, and time intercourse for then.

The 12 day thing - I am really not sure where that number comes from, and that’s untrue. I’ll use myself as an example of why this could be disasterous if you’re trying to avoid a pregnancy.

I ovulate on day 14 of my cycle, on average (I have 18 months of temperature tracking in the database). Sperm can live for up to five days in ideal circumstances. My husband and I could, theoretically, have sex on day 9 of my cycle, his sperm live for five days, get up in to my fallopian tubes, and fertilize as the egg drops. So, for us, sex after day 9 could mean pregnancy. The caveat is that some women ovulate much earlier then me, say day 9. If she has a five day period, and she has sex on the fourth day of her period, theoretically, she could still get preganant (sperm live for five days to day 9, she ovulates, bam, baby!).

Also, we’ve learned that having sex every day during a fertile period isn’t always the answer, especially in some cases of male-factor infertility. If he has only a few swimmers, it’s best to do it every two days to allow time for build up of little guys. Too much can deplete the supply, giving them less of a chance of surviving the swim.

19

And completely useless if you’re trying to get pregnant.

I usually ovulate around day 18, and this month not until day 25 (an odd one).

Now, I’m trying to get pregnant too, but if I went with the 12 (or 14, which I see sometimes) day “rule”, I’d be timing sex for days when I’m not at all fertile, and not close enough to ovulation.

It’s a bad number to use all around, since there’s no way of knowing if it’s accurate for you unless you’re tracking your temperatures, and other fertility signs.

20

This is true too.

Also, even using an Ovulation Predictor Kit can’t guarantee anything, because some women gear up for ovulation (positive on the OPK), then for some reason she doesn’t O and ends up Oing later, or not at all.