Prenatal Development and Care

Ovulation

Ovulation happens each month when one of a woman's two ovaries releases a mature egg. It happens about two weeks after the first day of her last menstrual period.

A man may ejaculate 40 million to 150 million sperm, which start swimming upstream toward the fallopian tubes on their mission to fertilize an egg. Fast-swimming sperm can reach the egg in a half an hour, while others may take days. The sperm can live up to 48-72 hours. Only a few hundred will even come close to the egg, because of the many natural barriers that exist in a woman's body.  

The Very Beginning

Moving Into the Fallopian Tube

After the egg is released from the ovary, it travels into the fallopian tube. It stays there until a single sperm fertilizes it.

Fertilization – The union of a male sperm cell and a female egg cell (also known as conception)

Fertilization: Sperm Penetrates EggIt  takes about 24 hours for a sperm cell to fertilize an egg. When the sperm penetrates the egg, the surface of the egg changes so that no other sperm can enter. At the moment of fertilization, the baby's genetic makeup is complete, including whether it's a boy or girl.

The Cells Start to Divide

Zygote – The cell that results from fertilization

The fertilized egg starts growing fast, dividing into many cells.

The zygote begins to divide and travel through the fallopian tube. It continues to divide many times, forming a cluster of cells.

It leaves the fallopian tube and enters the uterus three to four days after fertilization. In rare cases, the fertilized egg does not leave the fallopian tube. This is called a tubal pregnancy or ectopic pregnancy and is a danger to the mother.

ImplantationAfter it gets to the uterus, the fertilized egg attaches to the lining of the uterus, or endometrium. This process is called implantation. The cells keep dividing.

Pregnancy Hormones

Within about a week of conception, a hormone called human chorionic gonadotropin (hCG) can be found in the mother's blood. It is produced by cells that will become the placenta. The hormone will show up on a blood or urine pregnancy test at the doctor's office. But it usually takes three to four weeks for levels of HCG to be high enough to be detected by home pregnancy tests.

Baby's Development

After the egg attaches to the uterus, some cells become the placenta while others become the embryo.

After about two weeks, the zygote becomes an embryo. An embryo is a cluster of cells that develops between the third and eighth week of pregnancy.

This group of developing cells is called the fetus after about eight weeks.

1. Picture of First Trimester (4 Weeks)

                                                                                                                                                   

4 Weeks

The Growing EmbryoThe cells of the embryo will continue to divide as it grows. Eventually, three layers of tissue are formed. Later these layers develop into various body systems. One layer becomes the respiratory and digestive systems. A second layer develops into muscles, bones, blood vessels, and skin. The third layer forms the nervous system, sense organs, and mouth.

Structures Outside the Embryo

•Amniotic Sac – a thin, fluid filled membrane that surrounds and protects the developing embryo.•Umbilical Cord – a ropelike structure that connects the fetus with the mother’s placenta.•Placenta – a thick, blood-rich tissue that lines the walls of the uterus during pregnancy and nourishes the embryo.

First Trimester (0 - 14 Weeks)

0 – 2 weeks - A zygote may float freely in the uterus for 48 hours before implanting. The spinal cord grows. The brain, ears, and arms begin to form. The heart begins to beat.

3 – 8 weeks – The embryo is about 1 inch long at 8 weeks. The mouth, nostrils, eyelids, hands, fingers, feet, and toes begin to form. The nervous system and cardiovascular system are functional. By week 8, The baby is now a little over half an inch in size.

9 – 14 weeks – The fetus develops a human profile. Sex organs, eyelids, fingernails, and toenails develop. By week 12 it can make crying motions and may suck its thumb. The baby measures about 2 inches.

8 Weeks

3. Picture of First Trimester (12 Weeks)

                                                                                                                                                   

12 Weeks

2nd Trimester (15 - 28 weeks)

4. Picture of Second Trimester (16 Weeks)

                                                                                                                                                    15 – 20 weeks – The fetus can blink its eyes and becomes more active. The body begins togrow, growth of the head slows and the limbs reach full proportion. Eyebrows and eyelashes develop. At 20 weeks, the baby weighs about 10 ounces and is a little more than 6 inches long

16 Weeks

5. Picture of Second Trimester (20 Weeks)

                                                                                                                                                   

20 Weeks

20 Weeks - Time for an Ultrasound

An ultrasound is usually done for all pregnant women at 20 weeks. During this ultrasound, the doctor will make sure that the placenta is healthy and attached normally and that your baby is growing properly. You can see the baby's heartbeat and movement of its body, arms, and legs on the ultrasound. You can usually find out whether it's a boy or a girl at 20 weeks.

Shown here is a 2D ultrasound (inset) contrasted with a 4D ultrasound, both at 20 weeks.

21 – 28 weeks – The fetus can hear conversations and has a regular cycle of waking and sleeping. Jerking motions may be felt when fetus hiccups. It may also sense begin to sense upside down in the womb since the inner ear is fully developed.

Weight increases rapidly. By 24 weeks, the fetus weighs about 1.4 pounds and is about 12 inches long. The fetus may survive if born after 24 weeks, but will require special medical care.

24 Weeks

By 28 weeks, the baby weighs about 2 pounds, 6 ounces, and changes position often. If the baby isdelivered prematurely now, there is a good chance the baby would survive. 28 weeks is the time to register for birthing classes. Birthing classes prepare the mother and father for many aspects of childbirth, including labor and delivery and taking care of newborns.  

28 Weeks

3rd Trimester (29 weeks to birth)

32 Weeks

•The baby weighs almost 4 pounds and is moving around. •The baby's bones are fully formed, but still soft. •The baby's kicks and jabs are forceful. •The eyes can open and close and sense changes in light. •Lungs are not fully formed, but practice "breathing" movements occur. •The baby's body begins to store vital minerals, such as iron and calcium. •Lanugo begins to fall off. (Lanugo is the first hair produced by the baby's hair follicles. It is soft and downy like. It appears during pregnancy and begins to fall off before birth.)

The baby is gaining weight quickly, about ½ pound a week. Now, the baby is about 15 to 17 inches long and weighs about 4 to 4½ pounds. The baby's skin has fewer wrinkles as a layer of fat starts to form under the skin.

Between now and delivery, the baby will gain up to half its birth weight. A mother may notice a yellowish fluid leaking from your breasts. That is colostrum, and it happens to get your breasts ready for making milk. Most women go to the doctor every two weeks at this stage of pregnancy.

                                                                                                                                                   

Development at 36 Weeks

•The brain has been developing rapidly. •Lungs are nearly fully developed. •Body fat increases. •Movements are less forceful, but will feel stretches and wiggles. •The head is usually positioned down into the pelvis by now.

Babies differ in size, depending on many factors, such as gender, the number of babies being carried, and size of the parents. The baby's overall rate of growth is as important as the actual size. On average, a baby at this stage is the baby is about 16 to 19 inches long and weighs about 6 to 6½ pounds.

A pregnancy is considered "at term" once it's past 37 weeks.

                                                                                                                                                   

Picture of Third Trimester (37-40 Weeks)

                                                                                                                                                   

37 to 40 Weeks

By the end of 37 weeks, the baby is considered full term. The baby's organs are ready to function on their own. As the due date nears, the baby may turn into a head-down position for birth. Most babies "present" head down.

A mother's due date marks the end of her 40th week. The delivery date is calculated using the first day of her last period. Based on this, pregnancy can last between 38 and 42 weeks with a full-term delivery happening around 40 weeks. Some post-term pregnancies -- those lasting more than 42 weeks -- are not really late. The due date may not be accurate. For safety reasons, most babies are delivered by 42 weeks. Sometimes the doctor may need to induce labor.

At birth, the baby may weigh somewhere between 6 pounds, 2 ounces and 9 pounds, 2 ounces and be 19 to 21 inches long. Most full-term babies fall within these ranges. But healthy babies come in many different sizes.

Multiple BirthsIn most cases, fertilization results in one embryo. Twins, triplets, and quadruplets, known as multiple births, can result when multiple embryos are formed.

Identical twins develop from one fertilized egg and have the same genetic makeup. In the womb, they may share a placenta, but each usually has its own amniotic sac. Identical twins will look alike.

Fraternal twins occur when two eggs are released and are fertilized by two different sperm.

Each has its own placenta and amniotic sac. Fraternal twins can be different genders.

A Healthy PregnancyPrenatal care- the steps that a pregnant female can take to provide for her own health and the health of her baby.

Seeing a doctor regularly throughout the pregnancy will provide a new mother with the care and nutritional advice she needs.

What to Eat While Pregnant

• Calcium – helps build strong bones and teeth, as well as healthy nerves, muscles and developing heart rhythm

• Protein - helps form muscle and other tissue

• Iron – makes red blood cells and supplies oxygen to cells

• Vitamin A – helps in the growth of cells and bones and in eye development

• Vitamin B Complex – aids in forming the nervous system

• Folic Acid – critical in the development of the neural tube, which contain s the central nervous system

Fitness During Pregnancy

Physical activity can help a female maintain a healthy weight during pregnancy.

A Healthy Fetus

An expectant mother should avoid substances that can harm her or her fetus. She needs to be sure to avoid:

• Tobacco• Alcohol• Drug use• Hazards in the environment – lead, mercury, smog, radiation

Complications of Pregnancy

• Premature birth• Miscarriage• Stillbirth• Gestational hypertension• Pre-eclampsia• Ectopic pregnancy

Child Birth

Birth occurs in three steps:

Step 1: Labor

During labor, muscle contractions of the uterus become regular, stronger, and closer Together. This causes the cervix-the opening to the uterus- to dilate, or widen.

Step 2: Delivery

Once the cervix is fully dilated, the baby passes through the birth canal and emerges from the mother’s body. The baby takes its first breath and cries to clear its lungs of amniotic fluid.

Step 3: Afterbirth

The placenta is still attached to the baby by the umbilical cord. Contractions, although weaker, will continue until the placenta (now called the afterbirth) is pushed from the mother’s body.