Ovulation typically occurs once a month, about 14 days after the first day of menstruation. Ovulation is when one (or sometimes more than one) egg releases from the ovary, which is then caught by the fallopian tube. During sexual intercourse, a few milliliters (about one teaspoon) of semen is ejected, containing more than 100 million sperm. These immediately start swimming via the vagina up to the cervix. Once they enter the uterus, they swim upward into the fallopian tubes in a race to first reach the mature egg. If you have taken an ovulation test that shows a positive for ovulation, then you have a fairly good idea of the moment of conception.
Of the more than 100 million sperm, only a few 100 make it to the egg. But only one single sperm can fertilize the egg. The winning sperm penetrates the egg cell. As soon as the egg is fertilized, the surface of the fertilized egg changes, making it impermeable to penetration by other sperm.
Once the sperm is inside the egg, the sperm’s tail falls off, and the nucleus of the sperm meets the nucleus of the egg to fuse and form one cell. All of this happens just a few hours after the actual time of conception.
Some couples conceive with help, commonly called assisted conception treatments. Part of the procedure is done outside the body, such as in-vitro fertilization (IVF) and insemination.
Occasionally, a fertilized egg splits and develops into identical twins, or two eggs are fertilized by two individual sperm and develop into fraternal twins. It is also possible that more than two eggs are fertilized by individual sperm, but this is very rare. When this happens, the result is triplets or quadruplets.
To determine your current pregnancy week, calculate your pregnancy weeks from the first day of your last menstrual period. While it is commonly understood that pregnancy lasts about 40 weeks (280 days), you are technically usually pregnant “only” 38 weeks (266 days). So how does that work? Well, this is because conception can only take place after ovulation (14 days after the first day of your last period). That means that you are already two weeks into your pregnancy when the sperm meets the egg.
If you have entered the correct date for the first day of your last period, or the embryo transfer date if you had IVF, we can help you keep track of which week you are in. Your estimated due date may be adjusted a few days after your first ultrasound. If so, it’s easy to update this detail in the app.
From the moment you know that you are expecting, it’s important that you completely abstain from alcohol, nicotine and drugs. If you are taking prescription medicine, consult your physician to ensure that it is safe to continue with your medication. It’s also a good idea to abstain from alcohol, nicotine and drugs if you’re uncertain if you are pregnant or trying to conceive. The reason is that the fetus is incredibly delicate during the first weeks of pregnancy when all organs are forming.
We recommend taking 400 micrograms of folic acid per day to reduce the risk of health conditions, such as spina bifida, in the fetus. Ideally, you can start taking folic acid a few months before you want to conceive.