Lesson05
Chapter 4 - Prenatal Development and Birth
Now that we've talked about "where babies come from", let's talk about the actual development of those baby - starting just after conception. We'll start by reviewing some of the basics from the chapter.... Period of the Zygote (Germinal period) - the first 2 weeks of prenatal development. This is the process of cell division and growth. Differentiation - multiplying cells separate into two distinct masses, one inside the other. Outer cells become placenta, inner cells become embryo and then fetus. Implantation - attaches to uterus - 58% of all conceptions fail to implant properly and spontaneously abort. Period of the Embryo (weeks 3-8) - cells begin to separate into 3 layers of tissue that will become various body systems o a fold in the outer layer becomes the neural tube and will later become the brain and spinal cord o Growth follows specific patterns 1) Cephalocaudal - head to tail, meaning the top of the baby grows first and progresses downward towards the feet. This ensures that all organs necessary for life (such as brain) are as developed as possible. 2) Proximo-distal - center grows first, followed by extremities. If you've ever seen a baby born with cleft lip or palate - this would be an example again, organs (such as heart and lungs) develop before the outer features. by end of 1st month, cardiovascular system is functioning; eyes, ears, nose, mouth, arms & legs buds start to form. embryo is about 1/5” long by end of 2nd month, weight is about 1 gram and is 1” long. All basic organs except sex organs have formed. Begins resembling human being. Period of the Fetus (weeks 9-birth) - sex organs begin to take shape around week 9 Age of Viability - 22 weeks - the fetus is neurologically mature, meaning it is capable of regulating its basic body
functions like breathing, sucking and sleeping. A baby delivered at 22 weeks is "viable", meaning it can live outside the uterus. However, this is not a guarantee that the baby will survive - the close the fetus gets to 38 weeks gestation, the better the chances are of it surviving. 28 weeks - fetus weighs about 3 pounds and has a greater than 50% chance of survival. Remaining weeks - fetus is storing fat which provides a layer of insulation for when baby is no longer surrounded by mother’s warmth. The gain provides nourishment and vitamins. Gestation - depending upon which person you ask, you may hear 38 weeks or 40 weeks gestation is how long it takes from conception to delivery of a baby (ideally). The difference is the 2 weeks prior to conception - some doctors include this time and others don't. Everything mentioned above is ideal for the healthiest of deliveries and babies. However, while the healthiest of babies may have been conceived (meaning no genetic abnormalities), there are many things that can effect an unborn baby. And for many of those "things", we don't have an exact amount of exposure that will definitely effect the developing zygote, embryo or fetus - what we do know is that some exposure at some time during a pregnancy can cause problems....and without knowing the amount, the best we can do is try to avoid how much exposure we actually have to them....not only during the pregnancy, but for up to a year prior to conception, and for the length of time a baby is breast fed. Teratogens are those pesky little things we choose to eliminate from our existence, or choose to welcome into our worlds. We know all the dangers and risks associated with them, and then we make the conscious choice to change our exposures....or do we? Understanding the danger of potential teratogens isn’t the same as automatically avoiding the use of or exposure to such agents. Imagine that you have decided to become a parent. To ensure that your body is teratogen free for the year during which fertilization and gestation occur, considering the following potentially hazardous behaviors, take this test by scoring on a sheet of paper the following: 1. For each behavior or exposure you have experienced over the past month, assign a score of 1. 2. Estimate how difficult it would be for you to avoid the
proposed teratogen in the following year, by assigning a score of 0 for each you could change easily, 1 for each you could change without too much difficulty, 2 for each that would be difficult to change, and 3 for each you would consider virtually impossible to change or avoid. You've had a drink of alcohol You've either used marijuana or been in the room with someone else using marijuana You've either used tobacco or been in the room with someone else using tobacco You've ingested caffeine (soda or coffee) You've taken prescription drugs, such as prescription allergy medication, insulin or asthma inhaler (don't count birth control pills - if you're planning to become pregnant, you aren't likely to be taking these) You've used over the counter drugs, such as aspirin, cough medicine or allergy tablets You've used hard drugs, such as heroin or cocaine You've used or eaten foods made with artificial sweeteners You've used or been exposed to pesticides or cleaning solutions (if you work with children or clean your house, assume you've been exposed) You've been breathing polluted air You've been exposed to viral diseases, such as rubella, influenza or chicken pox (if you work with children, assume you've been exposed) Most people aren't even aware of how many teratogens they are exposed to daily, and the number they see at the end of this test can be quite alarming. Are you surprised by the score you received? One of the greatest problems is that many women are unaware of the fact that they are pregnant during the first few months (when all of the major organs are developing). Another is that many women don't get proper prenatal care early in their pregnancy (teen moms are at the greatest risk for this, since many don't tell anyone they're pregnant until they're "showing, which can be as late as 6-7 months into a pregnancy). If for any reason a fetus is exposed to teratogens, or not exposed to proper nutrition and care, there is the possibility of the following occuring: Fetal Alcohol Syndrome - leading known cause of mental retardation, and generally accompanied by distinct facial features. There is no known amount of alcohol consumption
which leads to FAS - it varies from person to person. One pregnant woman can drink several glasses of alcohol a day and have no effect on her unborn child, and another can have the occasional glass of wine and have a child born with FAS. Fetal Alcohol Effects - for many children not diagnosed with FAS, we are starting to recognize effects later in life. Generally by the time a child reaches elementary school, if they were exposed to alcohol during pregnancy, we start to notice differences in behaviors from other children. FAE looks quite similar to Attention Deficit Hyperactivity Disorder, in that attention spans are quite limited, and their behaviors are more noticeable. The problem with FAE is that it tends to get misdiagnosed and labeled ADHD, and many children are put on medications for ADHD - so what's happening is we're medicating children with alcohol exposure, and these children are more prone to addiction. Many of these children are actually more intelligent than their peers, and tend to get bored easily (also similar to ADHD) - by challenging them and giving them more stimulation, they actually can do better in school than most children. Low Birthweight - less than 5 1/2 pounds o 1 in every 7 births is less than 5 1/2 pounds (low birthweight) Causes for low birthweight - maternal malnutrition, mothers poor overall health, poor health habits including drug use, genetic handicaps, prenatal infections, malfunction of placenta or umbilical cord, age of mother is less than 15 or more than 40, multiple pregnancies. o Very Low Birthweight - less than 3 pounds o Extremely Low Birthweight - less than 2 pounds o Preterm - born more than 3 weeks before due date. Preterm infants are prone to develop mental delays. 6 weeks early - at risk for brain damage from anoxia (lack of oxygen) or cerebral hemorrhaging o Small for Gestational Age - close to full term but weigh less than expected for full term newborn Now, lets talk about a happier part of pregnancy - the delivery! OK, maybe not the happiest "during", but certainly worth all of the pain and discomfort (at least according to all of the mom's I've spoken to!)
If you haven't delivered your own child or been present for a deliver, I'm hoping you've had a chance to talk about the experience with a mom during your interview. There are a lot of "changes" in how and where babies are delivered, but always a few constants. At least for now (unless you've seen Arnold Schwarzenegger's movie Junior"), these should be pretty much standard: A baby is delivered either vaginally (sometimes assisted by forceps or vacuum extraction) or by Cesarean Section. Most doctors are generally monitoring the babies to watch for Breech positioning (feet first, or "sunny side up"). There are several variations on where a baby can be delivered - delivery room in a hospital, at home with a midwife, underwater, under hypnosis, and lately several babies delivered in taxis on the way to the hospital. However and where ever someone chooses to deliver, this order is always followed for vaginal deliveries. For Cesarean Section, there may never be a labor. First Stage of Labor - beginning of contractions until the cervix is almost fully dilated Transition - fetal head moves into birth canal Second Stage of Labor - delivery of baby Third Stage of Labor - placenta is expelled Once a baby is born, there are several tests done to determine how healthy a newborn is. The most common is the APGAR, which measures heart rate, breathing, muscle tone, color and reflexes. These are measured using a score of 0 or 1, and done at 1 minute after birth, and repeated at 5 minutes after birth. A score of 7 is considered healthy, and a baby receiving a score of 6 or less is generally taken to the NICU (Neonatal Intensive Care Unit) for observation. From my experience, every parent is told what they're babies score is, but very few parents ever find out what the score means. While this score is actually fairly accurate at determining problems associated with any of the five areas measured, it really don't give any indication of future developmental abilities. The Brazelton Neonatal Development Assessment Scale is much more accurate at determining lifetime developmental potential, very few hospitals will complete a Brazelton assessment without having it requested by the parents. In addition, not all hospitals have care givers trained to provide Brazelton assessments. If a baby scores 6 or under on the APGAR, the baby is most likely
taken to the NICU. Where the baby is placed within the unit actually has quite a bit to do with potential development. If a baby is placed in an isolette (armholes exist for any contact with baby, but "skin to skin" contact isn't allowed), which is generally done for a baby weighing less than 3 1/2 pounds, the baby is less likely to bond quickly with their parents, and the parents are less likely to bond quickly with their newborn. Bonding, or attachment, has quite a bit to do with the relationship between parents and child, as well as the development of skills down the road. We'll talk more about this development in the next few chapters, but you should know now that the more a newborn feels attached to his/her caregivers, the more the baby is talked to and help, and the sooner they feel confident to use motor skills and language and to explore their surroundings. Babies who don't bond, or who can't bond because of the need to keep them in an isolette (generally because their immune system isn't fully developed, or because they will burn more calories with human contact), the more likely that baby will be held less and interacted with less.
Some additional resources which you may find interesting: http://www.pregnancyguideonline.com/ This is a week-by-week guide of the developmental changes that an expectant mother and her developing baby will go through. Also suggested is a list of books to complement the various stages of change.