Conception and Pregnancy

Question 1

Spermatogensis

Answer 1

Upon ejaculation (3-5 ml), most sperm do not survive more that 48 hours within the female reproductive tract
The alkaline nature of sperm protects them from vaginal acidity

Question 2

Cryptorchidism

Answer 2

undescended testes

Question 3

Oogenesis

Answer 3

Primary oocyte - made when born
Secondary oocyte - develops and starts meiosis monthly (only completed with fertilized - zygote)

Question 4

Hypothalamic-pituitary cycle

Answer 4

decrease of progesterone and estrogen from hypothalamus
the release of GnRH stimulating LH and FSH
Luteinizing hormone; rupture of follicle and conversion of ovum to the corpus luteum
Follicle stimulating hormone: starts at menstrating causing ovum to mature

Question 5

Uterine cycle

Answer 5

Proliferation phase - estrogen causes proliferation of ovarian mucosa until ovulation
Secretory phase - progesterone causes maturation and secretion of uterine glands
Ischemic Phase - blood supply to lining stops and lining prepares to slough

Question 6

Ovarian cycle

Answer 6

Follicular phase - estrogen increases
Ovulation - day 14 mature ovum
Luteal phase - the follicle develops into the corpus luteum, increased progesterone maintains the uterine lining
Ischemic Phase - progesterone falls

Question 7

Implantation

Answer 7

occurs 6-10 day post fertilization

Question 8

Gestational age

Answer 8

Weeks of pregnancy is always counted from the women’s last menstrual period (LMP)
Since ovulation doesn’t occur until Day 14, the moment fertilization occurs, the zygote is already considered to be at 2 weeks gestational age
When the women misses her first period (approx. Day 28), the embryo has been developing for 2 weeks but is considered 4 weeks gestational age

Question 9

Phases of fetal development

Answer 9

Pre-embryonic - conception to day 14
- Prior to placental function, it is a cavity that forms, helps transport maternal nutrients and oxygen to the embryo via diffusion
- Creates blood cells and plasma
- Cellular replication, blastocyst formation, inital devel of embyonic membranes, primary germ layers
Embryonic
- day 15-week 8 (post conception)
- teratogens are the biggest threat
- all organ systems and structures are in place
Fetal
- week 9-birth
- viability - ability to survive outside the uterus

Question 10

Shunts

Answer 10

Ductus arteriosus = fetal circulatory pathway where fetal blood bypasses the lungs because fetal lungs do not provide gas exchange.
Ductus Venosus = fetal circulatory pathway where fetal blood oxygen-rich blood from the umbilical vein (placenta) bypasses fetal liver and enters inferior vena cava.
Foramen Ovale = an opening between fetal atria were deoxygenated blood from the fetal legs and abdomen and returning from the fetal lungs flows into the left ventricle and to the aorta.

Question 11

Purpose of fetal shunts

Answer 11

Bypass fetal lungs
Route oxygenated blood into circulation quicker

Question 12

Umbilical cord

Answer 12

1 umbilical VEIN – carries oxygenated & nutrient rich blood into fetal circulation
2 umbilical ARTERIES – carry blood from EMBRYO to the placenta where it releases wastes & gains nutrients & oxygenated blood “Away”

Question 13

Wharton’s jelly

Answer 13

connective tissue on cord that prevents compression

Question 14

Amnion

Answer 14

Inner membrane
Fills with amniotic fluid

Question 15

Chorion

Answer 15

Contains placenta
Outer membrane

Question 16

Polyhydramnios

Answer 16

too much amniotic fluid

Question 17

Oligohydramnios

Answer 17

too little amniotic fluid

Question 18

What is normal volume of amniotic fluid?

Answer 18

700-1000 mL at term

Question 19

Role of amniotic fluid

Answer 19

Maintains a constant temperature for the fetus

Provides oral fluid for babe to practice breathing and swallowing (muscle memory)

Cushions the fetus from trauma

Allows freedom of movement for musculoskeletal development
Prevents the fetus from becoming entangled in amnion or cord

Question 20

Placental function

Answer 20

Manufacturing warehouse - protein production, stores proteins, calcium and iron
Endocrine function - manufactures hormones
Transport function - delivery of oxygen, nutrients and excretion, heat transfer

Question 21

Placental Hormones

Answer 21

1. Human Chorionic Gonadotropin (hCG) - pregnancy hormone detected in pregnancy tests,
2. Human placental lactogen (hPL) - stimulates maternal metabolism to supply nutrient for fetal growth
3. Estrogen - uteroplacental blood flow, growth
4. Progesterone - relaxation and maintenance

Question 22

Trimesters

Answer 22

1 trimester - organogenesis (conception)
2 trimester - growth and development ( 13-26 weeks)
3 trimester - storage (27-birth)

Question 23

Teratogens

Answer 23

Any substance that can cause abnormal fetal development

hot tubs/baths, meds, occupational hazards, x rays, alcohol smoking, chemicals, infectious diseases, live immunizations

Question 24

Signs of pregnancy

Answer 24

Presumptive: changes felt by the woman (e.g., amenorrhea, fatigue, breast changes)
Probable: those changes observed by an examiner (e.g., ballottement, pregnancy tests)
Positive: those signs attributed only to the presence of the fetus (e.g., hearing fetal heart tones, visualizing the fetus, palpating fetal movements)

Question 25

What is the first biochemical marker for pregnancy?

Answer 25

Human chorionic gonadotropin (HcG)
can be seen in urine as soon as 7-8 days before the expected menses.