Between the early months following conception and childbirth, dramatic changes take place in the developing human fetus. From the initial embryonic stage in which the fetus is entirely dependent on the mother for survival, a fetus develops into an...
When a woman becomes pregnant, her body changes in many ways as she awaits the birth of her baby. Within the uterus, the fetus goes through several stages of development. Over a period of approximately 40 weeks, your baby will develop from a...
Fetus development proceeds over the course of 38 to 42 weeks of pregnancy. During that time, the fetus develops from a single, fertilized cell---called a zygote---into a full-term fetus, ready to be born and live outside the womb. Scientists have...
Whether you were trying to conceive or your pregnancy was a pleasant surprise, the first six weeks can seem overwhelming with different feelings of joy, excitement, nervousness and anticipation. During the first six weeks of pregnancy, your body...
Once conceived, babies develop inside their mother's womb for as long as 42 weeks, which is known as gestation. Unborn babies have a higher risk of suffering developmental problems when they are one day to about 12 weeks old, the National...
When the mother's egg is initially fertilized by the father's sperm, it is referred to as a zygote. This single cell develops into a ball of cells called the blastocyst, and then an embryo over the following two weeks. During week eight, it...
Over the course of approximately 38 weeks, a fertilized egg grows from zygote to embryo to fetus. The development that takes place before birth--referred to as prenatal development--follows a set of steps that are very consistent in order and...
Many factors can affect the development of a fetus. Environmental agents that can negatively affect prenatal development are called teratogens. Teratogen exposure tends to be most detrimental during the first trimester (the first three months) of...
If you are pregnant, you may have many questions about how to properly care for your body, and in turn your developing baby. What you eat, drink, and are exposed to can affect your child's inner environment. The amount of stress you are under, how...
Pregnant women really do not need to "eat for two." Although a slight increase in calories and nutrients is required to ensure proper fetal development and the mother's health, it is not necessary to double your diet. In fact, the American...
The period of human development before birth is known as the prenatal stage and is divided into three sections---the germinal period, the embryonic period and the fetal period. During the germinal period, which begins with fertilization and lasts...
A woman's pregnancy is typically dated in weeks, with the start date at her last menstrual period. The weeks up to the 12th week are typically known as the first trimester. The process begins with a sperm penetrating the egg, forming a zygote. The...
A man's sperm in the woman's fallopian tubes fertilizes an egg. It takes a few days for the fertilized egg to move through into the uterus where it will grow. The implanted cells become the fetus and placenta, providing nutrients, oxygen and...
The development of the human being is a dynamic process. Shortly after conception, the cells that make up the developing embryo will differentiate into three distinct tissue types known as germ layers: endoderm, mesoderm and ectoderm. Heart...
The twelfth week of pregnancy marks the end of the first trimester. At this point, the risk of miscarriage drops significantly. The risk of significant birth defects forming also diminishes after this point, while defects that might already exist...
The skeletal system is critical because of the role of bones both in protecting vital organs and for providing leverage for muscles. As a result, bone development begins well before birth so that the fetus is born with a full set of bones....
The digestive system is responsible for mechanically and chemically breaking down food into its constituent nutrient molecules, and absorbing these molecules into the bloodstream. From there, they become available to the body cells, which use them...
According to the National Institutes of Health (NIH), an embryo becomes a fetus in its ninth week of development. Between its ninth and 20th weeks, it has long, thin limbs and a well-defined face. Its genitals are defined, and the first buds...
Folic acid, also known as folate and vitamin B9 is involved in several bodily functions including the synthesis of DNA and is therefore very important during growth. Initially in pregnant women, blood levels of folate decrease because of the rapid...
A 30-week fetus is only ten short weeks away from his due date, and development is proceeding at a ferocious pace. At this point, the baby has completed most of the development of major organs and is concentrating his efforts on growing larger,...
Pregnancy, while an exciting time in your life, can also leave you on the edge of your seat as you wonder how your baby is growing and developing inside you. Just as you mark each of his developmental milestones once he is born, knowing how his...
The human fetus develops according to a set of precisely ordered and timed stages. The mother's egg is fertilized by the father's sperm and becomes a zygote---a single cell containing a new, complete set of DNA. This zygote rapidly divides and...
Cigarettes contain many dangerous chemicals, with nicotine and carbon monoxide being among the most hazardous to your health. If you're pregnant, these poisons get into the placenta, which is the tissue that connects you to your baby and sends...
Regular exercise during pregnancy has many benefits for the mother and her child. Exercise can provide relief from fatigue and mood fluctuations and help with weight gain, backaches, swelling, constipation and sleep. Exercise can help prevent the...
New scientific evidence indicates that pregnant women who exercise are not only benefiting their own health, but they are improving the health of their unborn babies. Experts recommend engaging in mild to moderate exercise each day to improve...
Opiates are strong drugs derived from the poppy plant. Opiates include heroin, morphine, codeine and opium. Some opiates, such as morphine and codeine, are used to relieve pain, and others are drugs of abuse. When a pregnant woman abuses opiates,...
According to the Merck Manuals, 90 percent of women consume prescribed, social or illegal drugs during their pregnancy. Some drugs are essential for a woman's health and the fetus. However, they should only be consumed after consulting a doctor or...
Progesterone, an indispensable hormone before and during pregnancy, is produced by the corpus luteum in the ovaries until the eighth week of pregnancy. Later in the pregnancy, the placenta takes over the development of the hormone. Progesterone...
The first trimester is the stage in which an embryo officially becomes a fetus. It runs from week one to week 13, with the fetal stage beginning around week nine. At the end of this trimester, the fetus is about 3 inches long and it weighs about 1...
