Pregnancy and Prenatal Development
Dustin Patton
PSY205 – Human Growth and Development
Eastern Gateway Community College
8/4/2018
Pregnancy and Prenatal Development
Have you ever asked yourself when does life really begin? Do you feel that life really begins when you are born? Does life begin from the moment that you are conceived? The Period of Pregnancy and Prenatal Development in my opinion is one of the most fascinating developmental lifespans that we have and it all starts from day 1. The pregnancy and prenatal development period involve genetics and how you develop over time, the normal fetal development as well as problems within the development of the fetus, the birthing process and the psychosocial environment that the mother and fetus have to co-exist in with each other and lastly for those families that end up having complications with the development of the fetus throughout pregnancy leading to genetic or physical problems.

Human development is a continuous process that begins when an oocyte (ovum) from a female is fertilized by a sperm (spermatozoon) from a male. Cell division, cell migration,
programmed cell death, differentiation, growth, and cell rearrangement transform the fertilized oocyte, a highly specialized, totipotent cell, a zygote, into a multicellular human being. It is customary to divide human development into prenatal (before birth) and postnatal
(after birth) periods (Moore, Persaud, & Torchia, 2016).

Conception occurs when an egg from the mother is fertilized by a sperm from the father. In humans, the conception process begins with ovulation, when an ovum, or egg (the largest cell in the human body), which has been stored in one of the mother’s two ovaries, matures and is released into the fallopian tube. Ovulation occurs about halfway through the woman’s menstrual cycle and is aided by the release of a complex combination of hormones. In addition to helping the egg mature, the hormones also cause the lining of the uterus to grow thicker and more suitable for implantation of a fertilized egg. If the woman has had sexual intercourse within 1 or 2 days of the egg’s maturation, one of the up to 500 million sperm deposited by the man’s ejaculation, which are traveling up the fallopian tube, may fertilize the egg. Although few of the sperm are able to make the long journey, some of the strongest swimmers succeed in meeting the egg. As the sperm reach the egg in the fallopian tube, they release enzymes that attack the outer jellylike protective coating of the egg, each trying to be the first to enter. As soon as one of the millions of sperm enters the egg’s coating, the egg immediately responds by both blocking out all other challengers and at the same time pulling in the single successful sperm (“Introduction to Psychology”, 2015).

Genetic information links each new person to the human species in general and also to a specific genetic ancestry. The term “inherited characteristics” refers to two different kinds of heredity. The first includes all the genetic information that comes to us as members of the human species. Most inherited genetic information is shared by all human beings, such as patterns of motor behavior (e.g., walking upright), brain size, and body structure, including the proportional size of the head, torso, and limbs. Two of the most relevant of these species related characteristics are the readiness to learn and the ability to participate in social interactions. The second kind of heredity consists of characteristics that have been transmitted through a specific ancestry. Hair color, skin color, blood group, and height result from the genetic information passed on from one generation to the next (Newman ; Newman, 2018).

Carrier screening is a term used to describe genetic testing performed on an asymptomatic individual to determine whether that person has a mutation or abnormal allele within a gene that is associated with a particular disorder. Carrier screening can be performed for one specific condition or for multiple disorders. The likelihood of identifying someone as a carrier for an inherited genetic condition reflects the prevalence of the condition in a particular population. In the absence of a family history, the more prevalent a condition the greater the likelihood of finding a carrier. This fact has historically guided practitioners to offer genetic screening to those individuals at highest risk of carrying particular disorders based on the individual’s race, ethnicity, or family history (Romero, Rink, Biggio, & Saller, 2017).

When you talk to people who study genetics and fetal development, they look at pregnancy in a very different way. The three stages that they look at are the germinal stage (weeks 2 to 4), the embryonic stage (weeks 5 to 9) and the fetal stage (weeks 10 and on) (Weiss & Sadaty, 2018).

The germinal stage is one of the least known for most people. This begins as the egg and sperm meet in the outer third of one of the fallopian tubes. Once the two become one, a zygote results and it continues its journey toward the uterus. At this point, the body is not recognizing the pregnancy has occurred. It can take seven or more days to travel the length of the tube and deposit the fertilized egg in the waiting uterus. The uterus has built up a lining in anticipation of a fertilized egg. This entire journey has seen cell division going from a single cell. In the beginning, all of the cells are identical. It isn’t until the cells reach the eight-cell stage that they start differentiating the type of cells they will be. The inner cells begin to form what will be the embryo (Weiss ; Sadaty, 2018).

The embryonic stage is when the cells are now considered to be an embryo. Though now very distinctly human in origin, the embryo still does not look like what most of us picture when we think of a baby. The embryonic period is very critical because every organ system is formed. One system that gets a lot of discussion in this critical time period is the neural tube (what eventually becomes the spinal cord, nervous system, and brain). This begins to form 22 days after conception, about 36 days from the first day of your last period. Spina bifida and anencephaly are two types of neural tube defects that can occur, particularly when there is not enough folic acid in the body. This is one of the biggest reasons for the push for all women of reproductive age to take prenatal vitamins or at least folic acid. It can be very difficult to pinpoint pregnancy this early, particularly since about 50 percent of all pregnancies are unplanned (Weiss ; Sadaty, 2018).

The baby’s heart is also rapidly forming. It starts as a single blood vessel that begins to pulse around the fifth week of pregnancy. It is still too early to hear the this even using Doppler technology. This won’t happen until around week 10, although a transvaginal ultrasound can pick up tiny pixels fluttering as the blood vessel beats with activity starting around weeks six to seven. A baby’s heartbeat is much more rapid than an adult’s, but it starts slowly, picks up rapidly (heading toward 180 beats per minute), and then settles into the 120 to 160 range for the rest of the pregnancy in the fetal stage. The body is also forming (Weiss ; Sadaty, 2018).

You will see images with holes or dark spots that become nostrils, eyes, the mouth, and ears. You will also see arm and leg buds, rapidly changing to include joints (elbows and knees). You will see distinct finger and toe rays a bit later in this period. While the decision as to whether or not the baby is female or male was genetically decided at conception, every baby looks the same at this point externally (though the external sex organs are present, you cannot tell a clitoris from a penis). This embryonic stage is only five weeks long. By the end of this time period, the embryo will weigh about the same as a paper clip and be about an inch long, and yet possess nearly every organ system and structure needed for external life (Weiss ; Sadaty, 2018).

The term fetus is one that many people have heard. This is the technical name for the baby in the fetal stage and is Latin for “offspring” or “newly delivered fruit.” The fetal stage is seemingly less exciting. While everything is present, there are many nuances and much fine-tuning to prepare the fetus for life outside the womb. Between 12 and 14 weeks, you can just begin to differentiate the boys from the girls via external sex organs, though—even using ultrasound—it is hard to be accurate with sex determination at this phase. That is best done between weeks 18 and 22 during a fetal anatomy scan. A baby girl will be born with every egg she will ever have in her life inside her ovaries, while a baby boy does not have sperm in his testes (Weiss ; Sadaty, 2018).

Prenatal development is a complicated process and may not always go as planned. About 45% of pregnancies result in a miscarriage, often without the mother ever being aware it has occurred. (Moore ; Persaud, 1993) Teratogens include general environmental factors, such as air pollution and radiation, but also the cigarettes, alcohol, and drugs that the mother may use. Teratogens do not always harm the fetus, but they are more likely to do so when they occur in larger amounts, for longer time periods, and during the more sensitive phases, as when the fetus is growing most rapidly. The most vulnerable period for many of the fetal organs is very early in the pregnancy—before the mother even knows she is pregnant (“Introduction to Psychology”, 2015).

If a family has a history of genetic issues or if the mother is over age thirty-five, it is reasonable for genetic screening to be offered prior to or during pregnancy. Prior to pregnancy, a family may be screened for genetic diseases like Tay-Sachs disease, sickle cell disease, and others. Once pregnant, the focus of testing shifts to actually screening the particular pregnancy and baby for anomalies. Prenatal care begins once the pregnancy is confirmed and will continue through the completion of the pregnancy. This includes preventive care, screening, and treatment of complications and potential complications as they arise. It is also important to know that there are environmental factors at play that you may not have any control over. Some are inherent to your life. For example, if you were exposed to diethylstilbestrol (DES)—a synthetic form of estrogen that was prescribed to women from the 1930s to 1970s—as a fetus, you may have a greater risk of having some uterine anomalies or a miscarriage (Weiss ; Sadaty, 2018).

Miscarriage is the most common type of pregnancy loss, according to the American College of Obstetricians and Gynecologists (ACOG). Studies reveal that anywhere from 10-25% of all clinically recognized pregnancies will end in miscarriage. Chemical pregnancies may account for 50-75% of all miscarriages. This occurs when a pregnancy is lost shortly after implantation, resulting in bleeding that occurs around the time of her expected period. The woman may not realize that she conceived when she experiences a chemical pregnancy (“Miscarriage: Signs, Symptoms, Treatment and Prevention”, 2017).

The pregnancy and prenatal part of human growth and development is one of if not the most complex parts of the developmental lifespan time frame and in large part that is due to the unknown. What I mean from the unknown is throughout the whole pregnancy the female has to be monitored from day one to make sure that things are going to go as close as they can to plan. Throughout the developmental life span of pregnancy and prenatal there are so many factors to take into consideration when you are pregnant. While there is a chance that things could go wrong there is an even better chance that there won’t be any hiccups along the way. The birth of a child (son or daughter) is one of the hardest, but best time of a parent’s life as you will forever be connected to that child.

References
Introduction to Psychology. (2015, October 26). Retrieved from

6.1 Conception and Prenatal Development


Miscarriage: Signs, Symptoms, Treatment and Prevention. (2017, December 05). Retrieved from

Miscarriage


Moore, K., ; Persaud, T. (1993). The developing human: Clinically oriented embryology (5th ed.).

Philadelphia, PA: Saunders.

Moore, K. L., Persaud, T. V., ; Torchia, M. G. (2016). The developing human: Clinically oriented
embryology. Philadelphia, PA: Elsevier.

Newman, B. M., ; Newman, P. R. (2018). Development through life: A psychosocial approach. Boston,
MA: Cengage Learning.

Romero, S., Rink, B., Biggio, J. R., Jr., ; Saller, D. N., Jr. (2017). Carrier Screening in the Age of Genomic
Medicine. Obstetrics ; Gynecology, 129(3).

Weiss, R. E., ; Sadaty, A. (n.d.). How Your Baby Grows in Pregnancy. Retrieved from
https://www.verywellfamily.com/fetal-development-4013817#