When Egg Meets Sperm…
Life Spans
Unfertilized egg can only live for 24 hours
Sperm usually live for 48 hours (can live up to 7 days) in a women’s body
Fertilization
The fusion of a sperm and eggMillions of Sperm are released in the vagina
move up uterus & to the fallopian tubes
if there is an egg, fertilization occurs
ONLY 1 sperm can fertilize an egg! Once this occurs, a protective shield forms
(fertilization envelope) around the eggFertilized egg = Zygote
What’s Next?
Zygote divides into many cells moves into uterus
Ball of cells = blastocyst
Cells travel for 7-8 days
Attach to uterine lining & continue developing Called implantation
The Pathway
Implantation
Occurs when the embryo attaches to the wall of the uterus
Some women can feel this occur (feel light cramps)
Causes a hormone called hcG to be released Supports pregnancy what pregnancy tests use
After implantation: Pregnancy
Membranes develop around the embryo to protect & nourish it = placenta
More on pregnancy…
Umbilical cord: connects embryo to mom Transports oxygen & nutrients to embryo Removes waste products
At 8 weeks, embryo is called a fetus
Pregnancy lasts about 266 days 40 weeks or 9 months
Giving Birth
Oxytocin (hormone) triggers uterine wall to contract
Labor beginsCervix expandsBaby starts to emerge, head first cut cord
Cord will dry up/fall off becomes your belly buttonPlacenta must be delivered after baby
Miscarriages
Spontaneous end of a pregnancy Occurs when a fetus can NOT survive out of the womb
Types: Embryo stops growing very early no fetus forms Fetal heartbeat has stopped fetus has died
Causes: Genetic Uterine abnormalities, hormonal abnormalities Reproductive tract infections Tissue rejection
Risk Factors: diabetes, smoking, drugs, fertility issues, etc
Stillbirth
Baby has died during delivery or prior to birth
Causes: (many) Umbilical cord Diabetes Trauma Drugs, smoking Birth defects infections
Ectopic Pregnancies
Implantation occurs outside the uterus in: In fallopian tube *most common 95%* Cervix Abdomen Ovary
Pregnancy has to be terminatedSymptoms similar to pregnancy
Additional symptoms: bleeding, lower back pain, low blood pressure, dizziness, sharp stabbing pain in back/neck
Infertility
Inability to conceive Can be female or male
Options: Fertility drugs: side effects include multiples IVF (invitro fertilization): fertilization happens outside
the body Very expensive, possible multiples
Egg Donors/Sperm Donors Expensive, invasive for egg donors Would you want it?
Adoption Can be expensive, heartbreaking, and joyful
Why do Birth Control Pills Work?
Estrogen & progesterone pills fool your body into thinking you are pregnant Hence, you don’t ovulate (or shouldn’t), FSH & LH
stay low Effectiveness also depends on following directions
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