Dystocia à difficult labor.

Embryonic period: (3-8weeks) The circulatory system begins to pump small amounts of blood.

The mother and fetus do NOT share a common circulatory system. There is no mixing of the blood.

The fetus will get its O2 from the mother thru the umbilical vein (comes from the placenta). Waste products leave the fetus thru the umbilical arteries.

The fetus relies on 3 shunt-like structures to supply O2 and nutrients and remove its waste products.

(fetal circulation is on a separate page)

When the cord is clamped, the ductus venosus normally closes at that time and becomes a ligament.

Also at birth, when the cord is clamped, the left side will gradually increase in pressure and when it does, the foremen ovale shuts. Usually occures 2 hours after birth. Sometimes it does not always close, and there is an atrial septal defect.

The ductus arteriosus constricts as O2 levels rise in the NB. Will also become a ligament = ligamentum arteriosus. Occurs about 15 hours after birth. Will totally be closed at 3 months.

Placenta

Umbilical cord

Umbilical vein

Ductus venosus (shunt)

Portal vein

Liver Inferior vena cava

Right atrium (pressure is greater here)

Foreman ovale (shunt)

Left atrium (most of the oxygenated blood comes here)

Left ventricle

Aorta

To the fetus

Right atrium (some of the blood)

Right ventricle

Ductus arteriosis Lungs (As soon as it has all the O2 it needs there

Is a build up and that pressure causes it

To shunt)

Aorta

To the fetus

Processes of metabolism

Hypogastric arteries

Umbilical arteries

Umbilical cord

Placenta

^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^Fetal Development:

Pre-embyonic period: (1-3 weeks) During theis period is the utero-placental circulation beginnings and chorionic villi formation. In this period also, is the beginning of organ development. This is a critical period because the fetus is susceptible to teratogens (any substance or condition that could cause abnormal development of the fetus). Danger is even up to 8 weeks.

Embryonic period: (4-8 weeks) Umbilical cord is functioning. Arms and legs are distinguishable. Head is large (50% of entire size). Forming of facial features.

Fetal period: ( 9-40 weeks)

13-16 à Mom feels movement that can be described as a butterfly

flutter. Quickening: definition of this movement. After week 14, can hear heart tones with a doplar.

20 à Circulatory system is functioning fully. Fetoscope can be used to auscultate the heart beat.

17-23 à Will have fine downy hair called lanugo and a cheese-like substance that protects the skin called vernix.

24-27 à The baby is at age of viability. Each state will define their own age of viability. Some say it is 20 weeks.

28-31 à Lungs are mature enough. The fetus will move in response to external noises. Will start to see the lanugo diminish. Will get some subQ fat. Testis will descend into the inguinal canal.

32-36 à There is a decrease in vernix, lanugo and amniotic fluid.

37-40 à Placenta decreases in function.

40 weeks (+) or (-), is normal time. Anything over 42 is post term. Skin is dry and wrinkled and no vernix is present. When the placenta stops functioning, the O2 will be deprived in the fetus. The deprevation causes a relaxation of the anal sphincter and meconium will come out in the amniotic fluid. Meconium stained fluid is okay in a breech delivery.

Fraternal: dizygotic, 2 eggs, 2 sperm. Will be totally different.

Identical: monozygotic, 1 egg, 1 placenta, 2 umbilical cords.