The cervical entrance (os) is not only very small, but it is blocked by cervical mucus. During most times in the menstrual cycle, cervical mucus is highly sticky (G mucus) and represents an almost impenetrable barrier to sperm penetration.
Fallopian tube obstruction
Blocked or scarred fallopian tubes that prevent sperm from reaching the egg are a frequent cause of infertility, especially among African Americans. A history of pelvic infection, sexually transmitted disease or endometriosis increases your risk for fallopian tube obstruction.
A low sperm count is fewer than 15 million sperm per milliliter of semen or fewer than 39 million per ejaculate. Sperm must be functional and able to move. If the movement (motility) or function of your sperm is abnormal, the sperm may not be able to reach or penetrate your partner's egg.
Sperm must undergo the process of capacitation in order to have the “capacity” to fertilize an oocyte. If they reach the oocyte before capacitation is complete, they will be unable to penetrate the oocyte's thick outer layer of cells.
Antisperm antibodies, or ASA, are immune system proteins that destroy sperm. They can be produced when the body mistakes sperm for an invader and triggers the immune system to protect itself. Though rare, antisperm antibodies can be found in semen, blood, or vaginal fluids.
How many sperm do you need to get pregnant? It takes just one sperm to fertilize a woman's egg. Keep in mind, though, for each sperm that reaches the egg, there are millions that don't. On average, each time men ejaculate they release nearly 100 million sperm.
The concentration of sperm is what makes the semen cloudy and thick, so if your ejaculate is watery it is possible that you have a low sperm count. This doesn't mean you're infertile (so precautions to prevent pregnancy still need to be taken for couples that don't want to get pregnant).
A trained expert checks your sperm count, their shape, movement, and other characteristics. In general, if you have a higher number of normal-shaped sperm, it means you have higher fertility. But there are plenty of exceptions to this. A lot of guys with low sperm counts or abnormal semen are still fertile.
There's no "safe" time of the month when you can have sex without contraception and not risk becoming pregnant.
Plan B One-Step contains the hormone levonorgestrel — a progestin — which can prevent ovulation, block fertilization or keep a fertilized egg from implanting in the uterus.
You could be worrying that you never will. However, there are many possible reasons why you aren't conceiving, including ovulation irregularities, structural problems in the reproductive system, low sperm count, underlying medical problems, or simply not trying enough.
Fertility is most likely if the semen discharged in a single ejaculation (ejaculate) contains at least 15 million sperm per milliliter. Too little sperm in an ejaculation might make it more difficult to get pregnant because there are fewer candidates available to fertilize the egg.
Dietary changes that promote a higher sperm count include reducing the intake of trans fatty acids and increasing polyunsaturated fatty acid and vitamin D intake. Maintaining a healthful, balanced diet that includes plenty of fruits and vegetables is the best way to boost sperm count through the diet.
Fast-swimming sperm can reach the egg in a half an hour, while others may take days. The sperm can live up to 48-72 hours. Only a few hundred will even come close to the egg because of the many natural barriers that exist in a woman's body.
Early signs and symptoms include implantation bleeding or cramps, which can occur 5–6 days after the sperm fertilizes the egg. Other early symptoms include breast tenderness and mood changes.
Indications that implantation has happened can include bleeding and cramping. Implantation bleeding is spotting or light bleeding that takes place about 1–2 weeks after fertilization. It is usually short-lived and lighter than a normal period. The blood is often paler than menstrual blood or can be a rusty brown.
Semen is normally a whitish-gray color. Changes in semen color might be temporary and harmless or a sign of an underlying condition that requires further evaluation.
Causes of male infertility
Abnormal sperm production or function due to undescended testicles, genetic defects, health problems such as diabetes, or infections such as chlamydia, gonorrhea, mumps or HIV. Enlarged veins in the testes (varicocele) also can affect the quality of sperm.
Abnormal sperm have head or tail defects — such as a large or misshapen head or a crooked or double tail. These defects might affect the ability of the sperm to reach and penetrate an egg. However, having a large percentage of misshapen sperm isn't uncommon.
Have sex regularly. The highest pregnancy rates occur in couples who have sex every day or every other day. Have sex near the time of ovulation. If having sex every day isn't possible — or enjoyable — have sex every 2 to 3 days a week starting soon after the end of your period.