Prenatal development occurs in three periods: the period of the ovum from conception to 2 weeks, the period of the embryo from 2-8 weeks, and the period of the fetus from 8 weeks until birth. During the period of the ovum, the fertilized egg undergoes cell multiplication and implants in the uterus. In the period of the embryo, major organs and bones form along with the placenta, amniotic fluid, and umbilical cord to provide nourishment. By the period of the fetus, organs mature and the baby begins moving, sucking its thumb, and hiccupping.

1. Prenatal Development

2. Prenatal DevelopmentMonth by MonthPeriod of the OvumPeriod of the Embryo

3. Prenatal Development StagesPeriod of the Ovum (zygote)0-2 Weeks Conception / FertilizationCell Multiplication – single cell divides into 2 4 8…Implantation – cells attach to wall of uterusAbout the size of a pin head.

4. Period of the Embryo2 – 8 weeksFormation of most major organs and bones;Formation of placenta, amniotic fluid and umbilical cord; nourishment begins to passHeart begins to beatAmniotic fluid acts as a “shock absorber” and is replaced every 3 hours.

5. Period of the Fetus8 weeks - BirthOrgans mature and begin to function;Quickening – movements can be felt by the mother (4th – 5th month);Heartbeat can be heard with a stethoscope (approx. 5th month);Rapid weight gain in later months;

6. Vernix Caseosa : cheesy, thick substance which covers and protects baby’s skin;Lanugo: Downy fuzz which covers and protects baby’s skin;Fetal Position: Curled up, knees brought up- position of comfort;

7. Lightening: Baby moves lower into pelvis in anticipation of delivery;Fetus can suck its thumb, cough sneeze, yawn, & hick-up.

9. 6 weeks12 weeks16 weeks24 weeks36 weeks40 weeks

10. Period of the Fetus

11. Period of the Fetus

12. Period of the Fetus

13. Period of the Fetus