Just because you have not gotten pregnant on your own yet does not necessarily mean that you can't do so. Before we talk about decisions and what to do, let's start with some basic concepts.
A baby is a new human being who has some characteristics from the father's side and some characteristics from the mother's side.
All babies are different, because they have different genetic programming instructions that tell them exactly how to develop including what color eyes and hair to have, what shape of nose to grow and so on. These special instructions are encoded in the form of DNA, contained in a baby's chromosomes. What is really special is that a baby's DNA comes 50% from the father and 50% from the mother and combine to form a unique individual who is a little bit like each of the parents.
The way that a baby's father passes on his genetic information is via his SPERM. The way a baby's mother passes on her genetic information is via her EGGS. So in order to have a baby, we need sperm and eggs. We also need a friendly environment in which the sperm and eggs can find each other and come together to form a fertilized embryo. We then need a safe home for the embryo to grow.
Couples who have trouble getting pregnant either have a problem with SPERM, a problem with their EGGS or a problem with the internal environment. Many times, there are multiple problems in more than one of these areas.
It's easiest to answer this question by thinking in terms of eggs. In general, each month, a woman releases an egg. Obviously, not all released eggs result in pregnancy. Instead, each released egg has a certain CHANCE that it will be fertilized and form a healthy baby. The chance of this happening is approximately 25%. In other words, if a normal healthy reproductive-age couple of average fertility are not practicing any form of birth control, then the odds of pregnancy for each released egg is about 25%, as long as they are having sex some time near the window period surrounding that ovulation. Even the world's most fertile couples are not expected to instantly get pregnant 100% of the time.
The problem is that this average magic number of 25% is not universally true for all couples. Some couples of super high fertility might have a 35% chance or higher of pregnancy for each released egg, while other couples of lower fertility might have a 2% chance or lower per egg. The actual % chance that each couple has is determined by the qualities of the eggs released, the nature of the sperm and the status of the anatomic environment where fertilization and implantation are to take place.
SUMMARY: You are your spouse have a magic number that represents your chance of getting pregnant each time you ovulate. An average expectation is 25%, although some couples have higher chances and others have lower chances.
There is no single test that will tell you exactly what your monthly chance of conceiving is. We can only estimate this through putting together information from SPECIFIC INFORMATION AND TESTING and from PAST HISTORY.
SPECIFIC INFORMATION refer to factors such as age and health condition.
SPECIFIC TESTING refers to things such as semen analysis, HSG, hormonal testing.
PAST HISTORY refers to how many months you have or have not gotten pregnant already in how many months of trying.
Typically, many couples start out their relationship with a CONTRACEPTIVE PHASE, a time period where they actively try to avoid getting pregnant.
Then at some point, they stop fighting it, and progress to the PASSIVE PHASE. During this time, they go about their daily lives and have sex when they feel like it, without paying special attention to trying to get pregnant. The good news is that most couples will get pregnant during this time. On the average, couples who do not practice active birth control of any sort, and who have sex on random days 2-3 times/week can expect an 85% chance that they will be pregnant within six months. This number is lower in older couples.
By 6 months, it's normal for couples to get a little anxious. This is when they decide to go from the PASSIVE PHASE to the ACTIVELY-TRYING PHASE. This is when they research on the internet and take active control of their fertility by checking their ovulation with temperature charts and with urinary ovulation testing kits. They are still not wanting to get medical help yet, but want to try what they can on their own.
There are three important principles to heed during this phase.