A baby is conceived when a woman's egg is fertilized by a sperm cell. Conception therefore occurs after ovulation. A few days later, the fertilized egg that has travelled to the uterus is implanted in its lining and a placenta is formed. This process results in the production of human chorionic gonadotropin (hCG), a substance commonly known as the pregnancy hormone because it is responsible for many of the signs and symptoms associated with pregnancy.

Depending on the number of days that have passed since ovulation and fertilization, different signs and symptoms of conception will be experienced. These early symptoms may vary for each woman and pregnancy. Moreover, some women are more sensitive to these changes and after the first or second pregnancy they may immediately be able to tell if they are pregnant again. Some women experience mild symptoms, while others may have experience more discomfort. Typical timing of the signs and symptoms of conception may also vary, so while some experience them as early as a few days post-ovulation (dpo), others may notice them a few weeks later.

Common Signs of Conception and When They Occur

The best way to determine if a woman is pregnant is a pregnancy test, which may be either a blood or urine test for hCG. However, there are classic signs and symptoms of pregnancy that may occur a few days or weeks after conception or fertilization. These include the following:

A drop in basal body temperature on the day that implantation occurs. A woman may notice a light pink or brow stain in her underpants, which is called implantation bleeding. This is the earliest sign of conception. This may occur 6-12 days after ovulation, or typically 8-10 post-ovulation (dpo). It may be accompanied by lower abdominal pain or cramps that are similar to menstrual cramps, so they may be mistaken as the beginning of your period. These symptoms occur as the fertilized egg is trying to embed itself into the uterine wall.

If a woman suspects that she is pregnant, then she can take a blood pregnancy test and obtain a positive result as early as 10 days after fertilization. Beyond this benchmark, a urine pregnancy test may also be able to produce a positive reading, depending on the sensitivity of the test taken. Some pregnant women may test negative at this time, but a repeat blood or urine test can produce a positive result a few days later (on the 10th-14th day). A positive pregnancy test is obtained when hCG has been detected in the blood, urine, or in both.

Fifteen or more days after ovulation, a woman will miss her period and will notice an increase in her body temperature. This is due to the increasing levels of progesterone, a hormone that maintains the uterine lining to support pregnancy.

Another classic sign of pregnancy is morning sickness, although this symptom may be experienced throughout the day. This occurs when a woman feels generally sick, nauseated, and may be sensitive to certain smells. This may begin between the 2nd and 4th week after conception and can continue in the following weeks until the 13th to 14th week. Some women may not experience this at all, while in some it can be very uncomfortable, leading to a loss of appetite and weight. Other symptoms that may accompany morning sickness include vomiting, food aversions, or food cravings. These symptoms occur as a result of increasing estrogen levels, which slows down the emptying of the stomach.

Nipple discomfort or breast tenderness is a common symptom of pregnancy that occurs in the early weeks (3rd-4th week) and may persist into the following months. This is accompanied by heaviness and enlargement of the breast, and is due to increased hormonal levels. During the 3rd or 4th month of pregnancy, the area surrounding the nipples (areola) may have darkened in color due to hormonal changes.

Fatigue is another symptom that may occur during the early weeks of pregnancy (3-10 weeks after conception), which may be due to increasing progesterone levels. Other factors such as low blood pressure and low blood sugar may also affect a pregnant woman's energy levels.

Increasing hormone levels can also cause other physical changes to occur in the body in preparation for child delivery, causing symptoms like lower back pain, frequent urination, and constipation. On pelvic examination done by a doctor, the woman's cervix may be softened, a definite sign of pregnancy. These may be observed during the 1st and 2nd months of pregnancy.

On the 4th to 5th months after fertilization, the baby's heartbeats may be heard over the mother's lower abdomen using a sonogram. The mother may also start to feel some movements in her lower abdomen, a sign of activity from her growing baby.

To summarize, here are the signs and symptoms of pregnancy according to the timing of events from ovulation and fertilization:

Recommendations

The classic signs and symptoms of pregnancy are commonly experienced due to hormonal and physical changes that occur after fertilization and implantation. However, the characteristics and timing of these changes may vary for each woman and pregnancy. Take a pregnancy test to determine if you are pregnant. If you obtain a positive result, consult your gynecologist to obtain proper prenatal care and evaluation.