For a regular 28-day cycle, pregnancy is estimated to be 280 days, or 40 weeks, from your last menstrual period, and 266 days, or 38 weeks, from the date of ovulation. Therefore, to calculate the most likely date of conception, you need to subtract 266 days from your estimated due date.

Baby’s Developments

Most pregnancies last around 40 weeks (or 38 weeks from conception), so typically the best way to estimate your due date is to count 40 weeks, or 280 days, from the first day of your last menstrual period (LMP). Another way to do it is to subtract three months from the first day of your last period and add seven days.

The short answer to the question, “Can I find out the exact day I got pregnant?” is, probably not. Determining the exact date of conception is difficult for several reasons. Some things to consider: First of all, pregnancy occurs when an ovulated female egg and and male sperm meet and fertilization occurs.

Men may contribute far more to a successful pregnancy than just sperm, with evidence suggesting seminal fluid primes a woman’s immune system to be more receptive to the foetus.

Fraternal twins occur when two eggs are released, and two different sperm fertilize each. These semi-identical twins, however, share 100 percent of maternal genetic material and 78 percent of paternal genetic material. During conception, researchers believe that two sperm simultaneously fertilized one egg.

Fertilization of an egg by two sperms results in the presence of a triploid chromosome set, including three sex chromosomes. Such a sperm fertilizing an egg by would yield a triploid condition. Second, an abnormal egg with two chromosome sets might be fertilized by a normal sperm.

What happens when sperm from two different males meet up? In displacement the incoming sperm physically push the sperm of the first mate out of a receptacle in the female where it is stored. Incapacitation is slightly different because it does not even require the sperm of the second mate.

Normal sperm have an oval head with a long tail. 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.

Can an abnormally shaped sperm fertilize an egg? Yes, it can. However, having higher amounts of abnormally shaped sperm has been associated with infertility in some studies. Usually, higher numbers of abnormally shaped sperm are associated with other irregularities of the semen such as low sperm count or motility.

Summary answer: Among men undergoing infertility evaluation, there is no significant relationship between semen parameters and defect rates in live or still births, even when considering mode of conception.

The most common abnormal morphologic abnormality is the “stress pattern” in which sperm heads are amorphous or tapering along with immature sperm forms. This pattern is a minor deviation from normal and typically due to heat stress (varicocele, hot baths, flu, fevers, illness).

No association between caffeine and sperm motility or morphology. Men with a high caffeine intake had about 14% higher concentration of testosterone than men with a low caffeine intake.

The quality of a man’s semen also seems to play a role. “Poor sperm quality can be the cause [of miscarriage] in about 6% of couples,” says Dr. Gavin Sacks, an obstetrician and researcher with IVF Australia. But there are probably multiple factors that, together, result in a lost pregnancy, he adds.

You can ovulate and become pregnant as soon as two weeks after a miscarriage. Once you feel emotionally and physically ready for pregnancy after miscarriage, ask your health care provider for guidance. After one miscarriage, there might be no need to wait to conceive.