The process by which an egg and your partner's sperm combine to create the beginnings of your baby.
Prior to conception, an egg was released from one of your ovaries and began to travel down the fallopian tube. At the moment of conception, one of your partner's sperm met, entered and fertilised your egg, which then sealed itself off to exclude all other sperm.
When your egg is fertilised by your partner's sperm, the genes or chromosomes from each of you combine to create a cell. This cell then starts to divide, becoming a collection of cells, or blastocyst.
The blastocyst continues to divide and grow, moving down the fallopian tube until it reaches the uterus (or womb) between 3 and 7 days later. Once in the uterus, the blastocyst will implant itself into the lining of the uterus, but before this happens, a change occurs. The blastocyst creates a liquid pocket in its centre. This fluid space creates a division in the blastocyst, resulting in an inner cell mass, which will form the embryo, and an outer trophoblast, which will form the placenta.
About a week after conception, the outer cells help the blastocyst to implant or embed into the lining of the uterus so that it can seek nourishment. As a result of the hormone changes following conception, the lining of the uterus has already become thicker and has an increased blood supply in preparation for implantation. The process of implantation usually takes about one week.
When are you most fertile?
A woman's most fertile period is from four to five days before ovulation to 24 hours afterwards. Basically, sperm cells can live for 72 hours but ova survive no more than 24 hours unless fertilised. More exactly it is believed that you are most fertile on the day before and the day of ovulation.
When should you have sex?
Basically, if you are trying to fall pregnant, then the best times to have intercourse are in the days immediately preceding ovulation and the day of ovulation. If you are not sure when you ovulate, one suggestion is that you have intercourse every second day from day 10 to day 18 of your cycle (the most likely period of ovulation for most women).
When should you worry?
Considering that at your most fertile peak (around 24) you only have about a 25% chance of falling pregnant during every cycle, most Health Practitioners will tell you not to even think about worrying for at least twelve months. Generally, specialists will not see you until you have been having regular intercourse and trying to fall pregnant for at least a year, or unless there are factors such as an irregular cycle, endometriosis or polycystic ovarian syndrome.
Remember, while it often seems that everyone else just suddenly fell pregnant, they may have been trying for some time. The best way to increase your chances of falling pregnant each month is as simple as identifying your fertile period and then ensuring you have sex at that time of the month.
If you still feel worried or cannot detect when you are ovulating, it is best to visit your GP to discuss your concerns.
Your chances of falling pregnant depend on a number of factors including:
- Age of couple (in particular the age of the woman)
- Timing of intercourse (with fertile periods)
- Lifestyle habits of the couple trying to conceive (See Preparing Your Body for pregnancy for more information)
If any of the following apply to you, then it may be worth a visit to your Health Practitioner to discuss your situation further:
Your periods are not regular and you cannot ascertain when you are ovulating
- You or your partner has, or has had a sexually transmitted disease
- You are concerned that your age or general health may be an issue
- You have already been trying for twelve months or more
- You have had problems with previous pregnancies
- You have endometriosis, PCOS or another condition