Updated: FEBRUARY 3, 2020
Pregnancy refers to the period of time that occurs between conception and birth. Once the egg is fertilized, it is implanted in the uterus lining before undergoing various stages of development. This development commonly spans over 38 weeks of pregnancy. Some woman may be pregnant for shorter or longer periods of time. Medically-speaking, pregnancy is divided into three separate trimesters, which each lasting an average of three months. Pregnancy can be multiple, in which case the woman gives birth to twins, triplets or even quadruplets.
While some people plan their pregnancies, unplanned pregnancies may also occur as a result of unprotected sex. In such cases, the mother can decide to carry on the pregnancy to birth or terminate the pregnancy. Birth control is commonly used as a way to indulge in penetrative sex without getting pregnant.
More About Pregnancy
Pregnancy occurs shortly after the sperm travels up the cervix to fertilize an egg. If the fertilization process was successful, the woman is said to have conceived and is pregnant. Nine months of pregnancy are punctuated by three separate trimesters, during which the embryo will develop into a fetus with functional organs. By the ninth month, the fetus drops lower into the mother's uterus.
While the most accurate way to predict pregnancy is through a blood test or a home pregnancy test gestation is normally indicated by symptoms that prepare the body to accommodate the fetus. The most common and first symptom of pregnancy is a missed period. This is followed by tender and swollen breasts as well as enlarged nipples. During the first trimester of pregnancy, the woman may also experience nausea and vomiting, especially in the morning. This is linked to hormonal changes like an elevated level of progesterone in the body. Frequent urination is another common sign, as the uterus starts to press down on the bladder. The mother may also experience weight gain, excessive tiredness and sensitivity to smells. Some women also experience food cravings.
Pregnancy might not even be visible until the second trimester. By then, the woman is approximately 15 weeks pregnant. By this point, the nipples are enlarged and darker to prepare for lactation. Both the heart rate and the volume of blood in the body are elevated by the end of the second trimester. The most common signs of pregnancy by the third trimester include stretch marks across the thighs, breasts and abdomen and hot flashes. Often considered as the most uncomfortable trimester, this period of gestation is also characterized by insomnia and a general sensation of discomfort as the baby starts to move around. Mild contractions, also known as Braxton Hicks contractions, may also occur at this stage.
By the last week of pregnancy, the baby gradually shifts until its head is pointing towards the opening of the cervix. In cases where the baby does not shift and remains breech, however, a C-section might be necessary. Otherwise, most women opt for a natural birth which may or may not include pain-numbing procedures like an epidural.