P REGNANCY 1

C ONCEPTION Cell: smallest unit of life that is able to reproduce itself. Sperm and ovum (egg) join which is called conception, they then form a zygote (fertilized egg). Ovum are produced and stored by the woman’s ovaries, each month one ovum is released which is called ovulation. It then travels toward the fallopian tubes. If the ovum is fertilized, it descends into the uterus, where the baby develops. If no fertilization takes place, the ovum will pass in the next menstrual cycle. Semen is the liquid that contains over 300 million sperm. Of these 300 million, only will survive and make its way to the ovum. 2

G ENETIC F ACTORS & THE U NBORN B ABY 3

Genetic factors are the traits passed through the genes. Each parent’s genes combine to make a blueprint (genome) for the unborn child’s growth and development. The genome will guide the growth and development as the baby develops as well as traits that will unfold throughout life (ex. If a male will have hair loss when they age). The genetic code is like instructions of what a person will be like, this is stored in our DNA. Our DNA is found in our chromosomes. 4

C HROMOSOMES AND G ENES Each human baby receives 46 chromosomes, 23 coming from the ovum and 23 from the sperm. Each chromosome contains about 20,000 genes, which determine a person’ individual traits. Human cells contain about a million genes. Sometimes one gene determines a trait, other times, a group of genes decides a trait. 5

D OMINANT AND R ECESSIVE T RAITS Dominant Traits: those that always show in a person even if only one gene of the pair is inherited from that trait. Ex. Mom has green eyes and dad has blue. Baby is born with blue eyes. The blue eye trait was dominant. Recessive Traits: typically do not show in a person unless both genes for that trait are inherited. Ex. Mom and dad have blue eyes, but baby is born with brown. The brown eye trait is recessive. Just because this trait is not apparent, doesn’t mean in won’t show up in later generations. 6

S EX C HROMOSOMES 22 out of the 23 pairs of chromosomes are alike in both males and females. The 23 rd pair is called the sex chromosomes, which determines the sex of the baby. Females have the chromosome pair called XX Males have the chromosome pair called XY. All female ovum contain an X chromosome, males sperm cells may either contain an X OR a Y chromosome…therefore the sperm always determines the sex of the baby. 7

M ULTIPLE B IRTHS 8

Multiple pregnancy: two or more babies develop in the same pregnancy. Chances of having spontaneous multiples Twins1 in 83 pregnancies Triplets1 in 7,000 Quadruplets1 in 572,000 Quintuplets1 in 47.5 million Sextuplets1 in 4 billion 9

Doctors are very concerned about the health of multiple birth babies, because many of them are born early and have very low birth weights (under 3 lbs.) This puts them at risk of severe vision, hearing, mental, and development disabilities. Twins are fives time more likely to die in their first year than single-birth children. Triplets are 10 times more likely. 10

F RATERNAL B IRTHS Fraternal births: Multiple babies develop from multiple eggs. Two eggs descend and become fertilized. Each egg is fertilized by two different sperm. Each child has a different genetic makeup May or may not be the same gender Each baby has its own membrane (chorion) in the uterus Babies will look different and show greater differences as they mature. Most common type of multiple birth. 11

I DENTICAL B IRTHS Children develop from a single egg that was fertilized by a single sperm. Right after fertilization, the egg splits into two or more children. If the egg does not completely split, the babies will be conjoined twins. They may share external body parts such as legs, or internal organs, such as a liver. This happens in about 1 in 250,000 births Babies from an identical birth have the same genetic makeup. Babies will be the same gender. Scientists do not know why the egg splits??? 12

Other than their genes, identical children are not exactly alike. Their fingerprints, palm prints, and footprints are similar, but not exactly the same. Some identical twins are mirror twins. They look the way you would if you look into a mirror. If one twin has a birth mark on the right shoulder, the other would have one on the left shoulder. One may be right-handed while the other is left-handed. 13

M IXED T YPES Multiple pregnancies may be both identical and fraternal if three or more children are born. Separate sperm fertilize two or more eggs (fraternal). Then, one or more of the fertilized eggs may split (identical). If all children are identical or all are fraternal, it is not a mixed pregnancy. Triplets are often from a mixed pregnancy, with two children identical and one fraternal. 14

S TAGES IN P RENATAL D EVELOPMENT Prenatal development: the changes that take place during the time between conception and birth. 15

G ERMINAL S TAGE Conception marks the beginning of the germinal stage. This stage lasts about the first two weeks of a pregnancy, until the baby can receive nourishment form the mother. 16

E MBRYONIC S TAGE Experts say this is the most critical stage because almost all body systems develop during this stage. At the end of this stage, the embryo looks like a small human being. The embryo has tiny arms, legs, fingers, toes, and a face. All major organs, such as heart, brain, and lungs are present. The heart begins beating. The embryo has no bones, but is supported by cartilage. The embryo now receives good and harmful substances from the mother. 17

F ETAL S TAGE When the bone cells start to replace cartilage, the baby has entered the fetal stage. From this point until birth, the baby is now a fetus. All parts of the body mature, and overall size increases quickly. By the 4 th month, the fetus will have grown enough to start showing on the mother. Between the 4 th and 5 th month, the mother will begin to feel the baby move. The baby can turn, swallow, and suck its thumb. 18

Quickening: when the fetus can move its head and push with the hands, feet, and limbs. By the 7 th month, most babies could survive if they were born early. This is called the age of viability. The babies brain has more control over body systems The likelihood of survival increases with every week of pregnancy after the 7 th month. Since the lungs are still developing, many babies born around the 7 th month need intensive care in hospitals and some may experience respiratory distress syndrome. 19

During the 9 th month: Baby receives immunities from the mother which will help prevent the baby from catching some diseases after birth. In most cases, the baby also turns to a head-down position to prepare for birth. 20