Notes on Prenatal Development: Three Stages and Influences

The germinal stage is the first stage of prenatal development, beginning with the zygote.
It lasts about $2$ weeks from fertilization.
The zygote is the tiny mass of cells that drifts down and out of the Fallopian tube and attaches to the wall of the uterus.
The fertilized egg is called a zygote.
Zygote divides for the first time within $24\text{-}$ $30$ hours after fertilization, and continues to divide roughly every $12$ hours.
Zygote division can lead to identical twins if the zygote splits into two clusters.
If two egg cells are fertilized, fraternal twins result.
Implantation is when the zygote burrows into the uterine wall and establishes connections with the woman’s blood vessels.
Implantation takes about $1$ week to complete and triggers hormonal changes that prevent menstruation.

The embryonic stage is the second stage of prenatal development, covering the period of the embryo.
This period lasts from implantation through the 8th week of pregnancy: from the time the zygote is embedded in the uterine wall until the end of week $8$ .
Once the zygote is completely embedded, it is called an embryo.
During this stage, rapid prenatal changes occur and groundwork for all body structures and internal organs is laid down.

By the 3rd week after conception, the embryonic disk folds to form three layers of cells:
- Ectoderm: will become the nervous system and skin.
- Mesoderm: will develop into muscles, skeleton, circulatory system, and other internal organs.
- Endoderm: will become the digestive system, lungs, urinary tract, and glands.

The final and longest phase of prenatal development is the fetal stage (period of the fetus).
Also known as the growth and finishing phase.
Lasts from $3^{\text{rd}}$ month to $9^{\text{th}}$ month.
By the $3^{\text{rd}}$ month, organs, muscles, and the nervous system start to become organized and connected.
The brain signals, and in response, the fetus can move: kicks, bends arms, forms a fist, curls toes, opens mouth, and sucks its thumb.
By the $12^{\text{th}}$ week, the external genitals are well formed, and the sex of the fetus is evident.
The heartbeat becomes stronger and can be heard with a stethoscope.
Between $17\text{-}20$ weeks, the fetus is large enough for the mother to feel movements.
The fetus is covered with vernix (a white cheese-like substance) and the body grows lanugo (white downy hair).
At around $20$ weeks, the fetus can be stimulated by sounds.

Prenatal development can be influenced by the environment.
Teratogens are environmental agents that can cause damage during the prenatal period.
The harm from teratogens depends on several factors: ext{dose},\; heredity,\; other negative influences,\; and the age of the prenatal organism}.
A teratogen’s effect depends on the dose (how much the mother is exposed to during pregnancy).
Toxins are examples of teratogens.

Activities in this module include experiential tasks and forum discussions.
Forum task focuses on Filipino practices and beliefs in child-rearing during prenatal, newborn, infancy, or toddlerhood stages (choose one).
Key questions include:
- Family and community roles in early nurturing,
- Filipino child-rearing practices and alaga (care),
- Personal realizations from the concepts learned,
- How to apply these insights in teaching practice as pre-service teachers,
- Include sources in APA format.
Practical implication: how prenatal knowledge informs pre-service teaching practices and culturally informed caregiving.

Asynchronous Task (p. 16):
1. Interview your own mother about her pregnancy experience with you.
2. Write down significant events and teratogens, if any, that may have influenced your prenatal development.
3. Write an insight paper on what you learned from the interview.
Activity 1 (p. 14): Interview your mother about pregnancy experiences and: (1) write significant events and teratogens, (2) write an insight paper about your learning and insights.
Milestones (p. 14): Document prenatal milestones observed in your interview.

The two most important days in your life are:
- The day you are born
- And the day you find out why
- Quote attributed to Mark Twain; source: IntuitiveGoddess.com

Gillibrand, R., Lam, V., & O’Donnell, V. L. (2011). Developmental Psychology. Pearson
Shaffer, D. R., & Kipp, K. (2014). Developmental Psychology. Wadsworth Cengage
Lifespan Development (n.d.). https://courses.lumenlearning.com/wm-lifespandevelopment/chapter/periods-of-human-development/