When Exactly Does Conception Occur?
by Lori Ramsey

The question is often asked exactly when conception occurs, especially if intercourse and ovulation are on separate days. There are many things that come into play here leading up to conception. I will explain each to give you a clearer picture of this wonderful process.

First, the body begins to prepare for ovulation on the first day of the menstrual cycle. This is known as day one of your cycle. It is during this time that the ovaries start preparing a few follicles to be the potential egg. After your bleeding period is over, your body starts producing estrogen, and the ovaries are being primed for ovulation. It is during this time that the cervical fluid becomes more “fertile”.

If the cervical fluid becomes fertile up to five days prior to ovulation and you have sexual intercourse, the sperm can live inside your fallopian tube during this time. For example, you can have sexual intercourse on Monday and not ovulate until Friday but still conceive. The chances of conceiving a girl are greater this way because female sperm tend to live longer than male sperm.

Given the fact that sperm can live up to five days inside a woman’s body, the egg only lives 12 to 24 hours. Rarely, a second egg will pop out 24 hours after the first. So tentatively there is about a week long window for conception to occur. But things have to be in tip-top shape for it to happen. In order for sperm to live longer than about 48 hours, there has to be good fertile-quality cervical fluid present. In order for the egg to be fertilized, there needs to be sperm present, or intercourse needs to be done within the first 12 hours of ovulation. With these circumstances in mind, it’s important to know when ovulation does occur through fertility charting.

I believe that conception happens the minute the sperm and egg combine. This happens within 24 hours after ovulation occurs. The body will not know it’s pregnant until the fertilized egg implants into the uterine wall, some 5 to 12 days after ovulation. Before implantation, there is nothing going on inside the body to detect pregnancy. When the fertilized egg implants, it starts sending signals to the corpus luteum to continue producing progesterone. It’s during this that minute levels of hCG – the pregnancy hormone - are released. During a healthy pregnancy, the hCG levels will double every other day. The earliest a pregnancy test would show a positive would be possibly on day 7 post ovulation, but it’s rare to see a positive pregnancy test that early. Even with the most sensitive tests, you will more stand a better chance of seeing a positive at around 10 days post ovulation.

Lori Ramsey of Stages in Pregnancy

©2006 by Lori Ramsey.  Reproduction without permission is prohibited.  All rights reserved.