Nursing 209

N209: Reproductive Health Study Guide • Sperm can live in vagina for 3-5 days after intercourse • Egg is capable of fertilization for 12-24 hours • At time of fertilization, genetic makeup is complete (including sex) Implantation • Occurs when embryo implants into the endometrium • Begins about six days after fertilization and is completed by about day 12 • Implantation bleeding: Bleeding that occurs at time of implantation and is often mistaken for a period Embryonic Period • Begins week five when cells multiply and differentiation begins • Organ development begins during this time, so there is the most risk for birth defects from infection and teratogens • At week 10, embryo becomes a fetus until birth Viability • Gestational age when fetus is capable of living outside of the uterus • No worldwide standard gestational age that defines viability Can be hereditary as a result of defective parental gene in DNA • Can also occur after fertilization as embryo splits during development Down Syndrome • Most often caused by Trisomy 21 (baby has three copies of chromosome 21 instead of two) • Results in delayed physical and mental development Sickle Cell Anemia • Hereditary disorder passed down by both parents • Sickle-shaped RBCs; can cause organ damage and severe pain Tay-Sachs Disease • Autosomal recessive pattern: The parents each carry one copy of the mutated gene but do not 3.10 Factors Influencing Fetal Growth Genetic Factors •

©2018

Achieve

Page 37

of 109