Why Do You Need So Many Sperm?
We’ve come a long way since infertility was considered a “woman’s problem.” Now it’s known that male factor issues contribute to as much as 40 percent of infertility. That’s why semen analysis is one of the series of tests performed to determine the fertility treatment you need as a couple, to start a family.
One of the key measures in semen analysis is sperm count. Most men produce millions of sperm. Why are so many sperm needed to get pregnant, when only one fertilizes the egg? How does the number of sperm affect pregnancy rates?
A Team with Millions of Members
It’s true that it only takes one sperm to fertilize an egg. But it takes millions of sperm for that one lucky guy to cause a pregnancy. Typically in intercourse, as many as 250 million sperm are released when the male ejaculates. Only hundreds survive the swim up to the fallopian tubes, however, which is where the egg has been released. Most of these sperm release an enzyme which makes it easier for a sperm to swim to the egg. Only the strong survive in this process, with the help of the other sperm in the ejaculate.
Sperm Count and Pregnancy Rates
A sperm count of 20 million or more per milliliter of ejaculate is considered normal. A recent study of sperm count and pregnancy rates with IUI, intrauterine insemination, which was presented at the American Society for Reproductive Medicine (ASRM) annual meeting in 2015 found that pregnancy rates fall steadily in IUI if a sperm count of less than 9 million per milliliter is present.
Sperm counts below 20 million or 9 million don’t mean you can’t get pregnant. It just may take more time, or, depending on what fertility issues the female partner has, you may need fertility treatments such as IVF and ICSI, intracytoplasmic sperm injection. Those treatments may make pregnancy possible even when sperm counts are very low, if the sperm are not defective. During IVF, or in vitro fertilization, eggs are combined with sperm in the lab so the eggs can be fertilized and develop into embryos for transfer to the woman’s uterus. ICSI is a procedure in which a single sperm cell is injected into an egg in the lab, causing fertilization. ICSI may be used when sperm counts are low or there are issues with the sperm’s shape or ability to swim. Some fertility centers routinely use ICSI as a part of their IVF procedure.
The female partner’s age is another important factor your fertility specialist will consider as well when recommending treatment. If both male and female fertility issues are present it may save time and increase your chances of success to start treatment with IVF. Your reproductive endocrinologist will examine all your tests and develop a plan which is personalized for your needs, to help you get the baby you want.