Module 3

Question 1

first stage of labour

Answer 1

begins when contractions start. At first, these contractions are usually weak, far apart, and irregularly spaced. As labour progresses for usually 12 – 24 hours for a woman’s first baby but shorter for subsequent children, contractions become close together and regularly spaced, or even uninterrupted, and very strong.

During this time, the cervix is dilating to 10 cm to allow the baby to pass through.

Question 2

2nd stage of labour

Answer 2

Once a woman’s cervix is sufficiently dilated, she’ll feel a strong urge to push during contractions and the second stage of labour begins. Crowning is when the top of the baby’s head appears. The head will come first, usually facing down, and changes to a cone-like shape that will resolve itself after a couple of days or weeks. The baby will then rotate a bit toward the side to allow the shoulders to come next, one at a time

Question 3

3rd stage of labour

Answer 3

Finally, the rest of the baby comes out quite easily, and the umbilical cord can be clamped and cut. This stage can take up to 1 hour for first babies but is shorter if a woman has given birth before.
The last stage is often forgotten about, maybe because it’s shadowed by the baby’s birth. In stage 3, which lasts for only about 10-15 minutes, the placenta is expelled from the uterus.

Question 4

Apgar score

Answer 4

The Apgar score is a quick way to get an approximate idea of whether the baby is healthy.

Health care professionals look for 5 different vital signs: appearance of skin tone, like whether the baby is blue, which would suggest that they aren’t getting oxygen, pulse or heartbeat, breathing, muscle tone, and the presence of reflexes, which are truly innate, unlearned responses to stimulation.

The baby is scored between 0 and 2 points on each vital sign, where higher scores indicate good physical condition and lower scores indicate the need for emergency care.

Question 5

Brazelton Neonatal Behavioral Assessment Scale, or NBAS

Answer 5

For a more comprehensive assessment for babies up to 2 months, the Brazelton Neonatal Behavioral Assessment Scale, or NBAS, is often used. It includes many more items that test the baby’s body functions, movement, sleep/wake states, and social interaction. It’s also commonly used in research.

Question 6

sucking reflex

Answer 6

is triggered when something is placed in a baby’s mouth.

help the baby feed, especially through breastfeeding.

Question 7

the rooting reflex

Answer 7

When their cheek is stroked, babies will turn their head toward that side and open their mouth, a response called the rooting reflex.

help the baby feed, especially through breastfeeding.

Question 8

withdrawal reflex

Answer 8

occurs when the baby is poked in the foot with a pin – they withdraw their foot just like you would if you touched a hot stove or poked yourself with something sharp.

This reflex should help prevent injuries like cuts or burns

Question 9

blink reflex

Answer 9

Babies also engage in the blink reflex when they hear a sudden loud sound or see a bright light, which would likely protect the eyes if something was coming at the baby.

Question 10

grasping or palmar reflex

Answer 10

grasping or palmar reflex happens when something is placed in the baby’s hand, like an object, your finger, or even your hair.

Babies will automatically grip the object, which probably helps them build muscles and brain pathways that will eventually allow them to grasp objects voluntarily rather than automatically.

Question 11

Moro reflex

Answer 11

Happens when a baby is startled from a loud noise, or a jolt, especially when the baby may feel like they’re falling. In this case, the baby throws out the arms and then hugs them inward.

The Moro reflex is thought to help a baby cling to their mother and avoid falls; the only problem is that humans can’t really do this.

Many researchers believe that this is a reflex that is leftover from our evolutionary past, because it may have benefited our ancestors.

Even though it might not help humans, it’s still around because it hasn’t been selected against, mostly because it doesn’t have any negative effects on survival or reproduction.

Question 12

Babinski reflex

Answer 12

which is when a baby’s foot fans out and then curls when it is stroked from heel to toe.

Because this reflex looks a lot like the grasping reflex except with feet, researchers suggest that once again, it may have benefitted our ancestors who did need to grab things with their feet, like other primates do.

Question 13

stepping reflex

Answer 13

When babies make stepping motions when they’re placed upright on a surface held by an adult.

This one is thought to be a precursor to later voluntary walking, kind of like the grasping reflex is a precursor to voluntary grasping.

The historical mystery though is why it disappears at around 8 weeks if babies don’t tend to walk until about one year of age.

Funnily enough, it’s only because the baby’s legs get too chubby to lift!

They’ll still engage in the stepping reflex if their legs are underwater because they’re more buoyant, or if they’re placed on a little baby treadmill that helps them move their legs a bit.

Question 14

reflexes

Answer 14

reflexes indicates a normally-functioning nervous system. Many will disappear within the first year as they give rise to voluntary movements instead.

Others stick around because they’re still important for survival, like the withdrawal or blink reflexes.

Question 15

newborns states

Answer 15

spend most of their time sleeping, usually for 16 – 18 hours every day. They don’t tend to sleep in large chunks though – they usually operate on a 4-hour cycle where they’re awake for 1 hour and asleep for 3. When they’re awake, they’ll typically cycle through three states: crying, waking activity, and alert inactivity.

Infants spend about 2 – 3 hours per day crying. Crying is an infant’s first form of communication, because it tells the caregiver that the baby needs something.

Waking activity is when the baby is moving in uncoordinated bursts and their eyes are open but unfocused – they are probably transitioning from sleep and so they’re not fully alert.

Finally, alert inactivity is when the baby is calm and and seems to be inspecting their environment. This is when the baby may be gazing at your face or at the space around them, learning about what they’re experiencing.

Question 16

Influences on prenatal development: nutrition

Answer 16

Micronutrients are also very important, including iron, calcium, zinc, and most vitamins, especially vitamin B9, which is also known as folic acid or folate.

As an example, a deficiency in folate can affect the very early development of the neural tube, which eventually becomes the brain and spinal cord. Between about 3 and 4 weeks of gestation, if the neural tube doesn’t close properly, a child may be born with spina bifida, which can cause an opening in the spine at birth that can make the baby prone to infection and need crutches or a wheelchair as they grow up.

One reason why doctors recommend that women start taking daily prenatal vitamins a few months before trying to get pregnant is that they will help ensure that there is enough intake of folic acid.

Question 17

Influences on prenatal development: stress

Answer 17

veryone experiences mild to moderate stress from time-to-time, but this kind of everyday stress is unlikely to harm a developing baby.

Chronic, or more intense stress can be cause for concern on the other hand.

Babies whose mothers experienced chronic stress are more likely to be born early or underweight, and they are more prone to attentional, behavioural, and cognitive problems when they’re older.

Severe, chronic stress causes the release of hormones that reduce oxygen flow to the baby, which interferes with development.

Stress also impairs the immune system, making a woman more likely to become ill, which can in turn have its own negative effects on prenatal development.

Stress also makes it difficult to lead a healthy lifestyle like getting enough sleep, exercising, eating healthy, and avoiding substances that people sometimes use to cope like caffeine, nicotine, and alcohol.

Question 18

Influences on prenatal development: Biological parents age

Teenagers

Answer 18

For teen mothers, it’s true that outcomes are poorer: children are at risk for premature birth, low birthweight, and academic and behavioural problems.

This is probably for two main reasons: the first is through social selection, meaning that certain kinds of teenagers are more likely to become pregnant, such as girls with conduct disorder, who are aggressive and prone to lying and rule-breaking.

They would then pass on their genes to the developing baby, and would probably also provide a poor environment in which to raise the child.

The second reason for poorer outcomes is because of social influence: pregnancy and birth can interfere with a woman’s ability to provide a positive environment for her child, like completing her education, obtaining a good job and providing resources, and having enough time to dedicate to parenting.

Programs aimed at helping teen mothers complete their education and learning positive parenting techniques can be helpful, and children tend to do a bit better if the mother lives with relatives who can offer financial and emotional support.

More research is needed on the influence of teen dads on children’s outcomes.

Question 19

Influences on prenatal development: Biological parents age

Older

Answer 19

there is a huge trend for women to be increasingly older when having their first child. Do children fare well when their mother is in her 30s or older?

Actually, they tend to do just fine, and in many cases, they have advantages over other children since they’re more likely to come from parents who are more mature, knowledgeable, and financially stable.

Biologically speaking, fertility starts to decline in a woman’s 30s, but the dramatic drop offs in fertility that supposedly happen in the mid 30s are not actually true: most women are still quite fertile during this time.

On the other hand, it is true that fertility drops off with age, especially in the early 40s.

The risk of miscarriage also increases, although it’s still low. For men, fertility also decreases with age, but much less dramatically: men are able to parent a child even into their 70s or later.

Question 20

Influences on prenatal development: Biological parents age

Older. Disorders and genetic mutations

Answer 20

Older age also increases the chances of certain disorders. For example, both female and male age increase the likelihood of Down syndrome in the developing baby, although major disruptions to chromosomes are more likely to come from the mother.

On the other hand, genetic mutations seem to be much more likely when fathers are older, but unaffected by the mother’s age. These genetic mutations make older fathers more likely to have children with autism spectrum disorder, schizophrenia, and dyslexia.

Question 21

teratogen

Answer 21

The term teratogen is used to describe anything that has a negative effect on prenatal development.

Question 22

thalidomide

Answer 22

In the 1950s and 60s, many pregnant women with morning sickness were prescribed a drug called thalidomide, which was thought to be safe.

Unfortunately, many babies started to be born with limb deformities: missing or deformed arms, legs, hands, and feet,

Question 23

fetal alcohol spectrum disorder, or FASD, or the most extreme form, fetal alcohol syndrome (or FAS for short)

Answer 23

These children have a host of difficulties, including slow growth, heart problems and certain facial characteristics like a small head, a thin upper lip, a short nose and smooth or flat skin between their upper lip and nose, and widely spaced eyes.

Behaviourally, these children can have severe attentional, cognitive, and behavioural problems.

One of the many reasons why alcohol has these effects is that it reduces the flow of oxygen and nutrients to the developing baby.

Question 24

Effects of smoking, marijuana use during prenatal development

Answer 24

Cigarette smoking is also very harmful for fetuses, since it constricts the mother’s blood vessels and also reduces the baby’s intake of oxygen and nutrients.

In fact, smoking can reduce the size of the placenta, so oxygen, nutrients, and wastes are not exchanged as easily.

This makes miscarriage more likely, as well as low birth weight, which puts the baby at risk for various other negative outcomes.

These other negative outcomes can include attentional, language, cognitive, and behavioural difficulties.

Even if a mother doesn’t smoke herself, frequent exposure to second-hand smoke also causes negative outcomes.

Less is known about the use of marijuana during pregnancy, but evidence suggests that it has similar negative outcomes as smoking cigarettes, including low birth weight attention problems, as well as difficulties with motor control.

One of the active ingredients in marijuana, tetrahydrocannabinol, or THC, is associated with cognitive and behavioural problems and premature birth, but researchers aren’t sure about cannabidiol, or CBD,

Question 25

Principles of teratogens

1.impact depends on genome

Answer 25

This means that the effects can be species-specific, and that they can even vary depending on the genetics of both the mother and her developing baby.

As an example, thalidomide was originally approved in part because animal studies on pregnant rats found that there were no negative effects–the problem is that limb deformities were specific to humans.

As another example, two women could drink the same amount of alcohol during the same times in pregnancy, and it’s possible that only one of the fetuses would be harmed.

This is because some women and babies are more vulnerable to the negative effects of alcohol than others because of their genetics.

Question 26

Principles of teratogens

2. Impact depends on timing

Answer 26

For example, in several studies that have been conducted on the babies of mothers who were pregnant during the Dutch famine of World War II, researchers found different outcomes depending on if the famine occurred early vs. late in pregnancy. It it occurred early in pregnancy, babies had worse outcomes, including an increased risk of depression, schizophrenia, heart disease, cancer, and diabetes. If it occurred late in pregnancy, babies tended to have low birth weight and were also more prone to diabetes.

In general, high doses of teratogen exposure during the period of the zygote lead to miscarriage.

Because the bodily systems aren’t yet developing during this stage, they can’t really be negatively affected, although the organism as a whole can die.

During the period of the embryo, many organ systems are highly vulnerable because they’re rapidly developing.

The fetal stage still contains some vulnerable organ systems, but most are prone to minor as opposed to major defects.

Some systems, like the central nervous system at the top, are vulnerable for a very long time, whereas others, like the limbs, have a shorter period, explaining why thalidomide only had a negative effect if taken in early pregnancy.

On average, the earlier the exposure to a teratogen, the worse the outcome.

Question 27

Principles of teratogens

3.impact is system(organ) specific

Answer 27

The third principle is that most teratogens affect specific organ systems, rather than everything that happens to be vulnerable at that time.

For example, thalidomide affected limbs specifically, even though other organ systems were also vulnerable in early pregnancy, and alcohol affects facial features and the brain.

Question 28

Principles of teratogens

4. Impact depends on dose

Answer 28

depends on the dose, or how much exposure the baby actually received.

Although doctors recommend that women abstain from alcohol completely during pregnancy, the occasional glass of wine consumed slowly is unlikely to negatively affect the fetus, whereas frequent, long- term binge drinking is almost certain to have negative effects.

The reason for extra caution is that a safe dose is mostly unknown, and would depend on each individual woman and baby since according to the first principle, some people are more vulnerable than others.

In general, the more exposure, the worse the outcome.

Question 29

Principles of teratogens

5. Impact can be delayed

Answer 29

in other words, not evident at birth.

Remember that alcohol, cigarettes, and marijuana can cause behavioural and cognitive difficulties that wouldn’t be obvious until a child was a little older, like when they’re in school.

As another example, a drug called diethylstilbestrol that used to be given to women to prevent miscarriages turned out to raise the risk of cancer for those babies when they grew up.

This means that sometimes it takes many years for researchers to identify a teratogen, since the negative effects might not be evident for many years.

Question 30

Delivery complications

Answer 30

Vaginal births are most common. In fact, babies acquire healthy gut bacteria during a vaginal delivery that may have later positive health implications, but more research is needed.

On the other hand, sometimes things don’t go quite as planned and a woman requires a Caesarian Section, or C-section, to get the baby out.

This is when an incision is made in the woman’s abdomen and the baby is surgically removed, which is a bit more risky than a vaginal birth, particularly for the mother.

Question 31

Why might a C-section be performed?

Answer 31

Sometimes it’s because labour just isn’t progressing and the baby needs to come out.

Other times, it’s because the baby isn’t in the right position, such as breech presentation when they’re aimed feet-first instead of head-first.

A prolapsed umbilical cord is when part of the cord comes out before the baby, which cuts off blood flow to the baby.

cephalopelvic disproportion, which basically means that the head—the “cephalo” part—is too big for the pelvis.

Pregnancy complications like problems with the placenta or health conditions in the mother like high blood pressure, gestational diabetes, or certain infections can also lead to a C-section.

Question 32

Small-for-date

Answer 32

when they are smaller and lighter than they should be for their gestational age, whether or not they’re premature.

Being small-for-date is more problematic – this suggests that the baby wasn’t getting enough oxygen an nutrients and failed to develop properly. If they’re under about 3.3 pounds, they may not survive. If they’re a bit heavier, they’re more likely to survive but they may have delayed cognitive and motor development.

Question 33

Prematurity

Answer 33

is when babies are born at least one week earlier than full term, which is 38 weeks after conception.

Babies can also be both premature, and small- for-date—so even smaller than they should be even though they’re early.

These babies are at the highest risk of complications.

Premature babies often need help breathing and regulating their temperature because they’re lungs aren’t developed enough and they don’t have enough fat, but most will survive if they’re born by 22 – 26 weeks if they are cared for in a well-equipped neonatal intensive care unit, or NICU.

Question 34

Female menstrual cycle

Answer 34

The first day of menstruation, when a woman gets her period, is considered the first day of the cycle, and this lasts for a few days.

Approximately 2 weeks in, an egg is released into the fallopian tube by one of the woman’s two ovaries, a process called ovulation.

A woman is most fertile a few days before ovulation, and sperm can survive up to 5 days while inside the woman’s body.

Once an egg is released, it will die within 12 to 48 hours unless it is fertilized by a sperm in the fallopian tube, a process called fertilization or conception.

Approximately 2 weeks after that, after the lining in the uterus has built up, a woman will get her period again and the cycle will start over if she’s not pregnant.

Question 35

Signs of ovulation

Answer 35

Before ovulation, women may notice an increase in sexual desire and in cervical mucus that has the consistency of egg whites: this kind of fluid actually helps sperm swim up the reproductive tract towards the egg.

The cervix—the low, narrow part of the uterus at the top of the vagina—will also soften and open a bit to allow sperm to pass through.

Some women experience some pain or cramping around ovulation, and some experience breast tenderness after, due to rising levels of certain hormones.

These hormones also raise a woman’s basal body temperature—her lowest temperature while at rest—which is why women who are trying to get pregnant often measure their own temperature each day when they wake up.

Question 36

Hormones in the female menstrual cycle

Answer 36

follicle-stimulating hormone (or FSH for short) causes follicles in the ovaries, which contain immature eggs, to produce mature eggs.

One of these follicles will kind of take over—the one that will eventually release the egg.

This process causes estrogen to rise, which then triggers a spike in luteinizing hormone (or LH for short – the pink line on the graph).

Luteinizing hormone is what causes the follicle to release the egg into the fallopian tube, which is ovulation, and it is also the hormone that is most commonly tested for in ovulation predictor kits because it can be detected in urine.

After ovulation, the now-empty follicle starts producing estrogen as well as progesterone, which helps the uterine lining prepare for implantation and raises basal body temperature.

If no fertilized egg implants into that lining, progesterone and estrogen will drop, as will a woman’s basal body temperature, and then she’ll get her period.

If implantation has occurred, the body starts producing human Chorionic Gonadotrophin (or hCG for short, shown by the grey line on the second graph), which keeps the empty follicle active.

HCG is sometimes called the pregnancy hormone and it’s also what pregnancy tests are detecting: it can also be detected in urine once the levels increase enough.

The empty follicle keeps raising levels of estrogen and progesterone, which will prevent the woman from getting her period.

Progesterone also keeps the woman’s basal body temperature high, which is another way to detect whether or not pregnancy has happened.

Question 37

Stages of prenatal development

Answer 37

Once an egg is fertilized by a sperm, prenatal development begins and goes through three stages, which aren’t the same as trimesters that people usually talk about when it comes to pregnancy. Trimesters are even divisions of the whole pregnancy period, but the stages of prenatal development are quite different in length

Question 38

Stages of prenatal development

The germinal or zygote stage

Answer 38

The germinal or zygote stage only lasts two weeks, from the time the egg is fertilized—when it’s called a zygote—until it is a ball of identical cells called a blastocyst and finishes implanting into the uterine lining. Once it’s finished implanting, it is called an embryo, which starts the embryonic stage.

Question 39

Stages of prenatal development

embryonic stage

Answer 39

This lasts 6 weeks and is the most dramatic in terms of development: all of the major organs start to form, and the organism goes from being a ball of identical cells to something with much more of a human appearance.

Question 40

Stages of prenatal development

The fetal stage

Answer 40

The fetal stage is the longest, lasting from 9 weeks after conception until birth, which usually occurs 38 weeks after fertilization.

The fetus’s main job is to grow and grow and grow, while organs also mature. Later on, fat develops to help maintain the baby’s temperature after birth.

Sometimes people say that pregnancy is 40 weeks, but they’re counting the first couple of weeks in a woman’s cycle before she has ovulated, when she’s technically not pregnant yet.

The reason this has been done historically is that it’s easier to figure out the first day of a woman’s menstrual cycle-–because she gets her period that day— than the day she ovulated, which she can only estimate if she’s been paying attention to her cervical mucus, basal body temperature, or cervical position and opening, or if she’s taken an ovulation predictor test.

If you look up what happens during pregnancy in online articles, the timeline given will usually be counting using the 40-week system, but we’ll stick with the more accurate 38-week system in our notes.

Question 41

Period of the zygote

Answer 41

begins when the sperm penetrates the egg in the fallopian tube.

The sperm and egg each contribute 23 chromosomes, which unite to form the new 46-chromosome genetic code of the new baby.

During the next 4 to 5 days, the fertilized egg cell continues to divide about every 12 hours, so one cell becomes 2, 2 cells become 4, 4 cells become 8, and so on.

It becomes a hollow ball of about 100 cells called a blastocyst with an outer layer of cells that will eventually become placenta, and an inner clump of cells that will eventually become the baby.

During the next several days, the blastocyst enters the uterus, attaches to its wall, and starts to implant into the wall.

About two weeks after fertilization, implantation is complete, which signals the beginning of the next stage of prenatal development.

Question 42

Period of the embryo

Answer 42

The period of the embryo lasts for only 6 weeks, but it might be considered the most dramatic.

First, three layers of cells form: the inner layer called the endoderm will become the lungs and digestive system, the middle layer called the mesoderm will become the muscles, circulatory system, and bones, and the outer layer called the ectoderm will become the skin, hair, and nervous system.

During the period of the embryo, the heart begins to beat and most of the major organs form and go through significant development.

The baby starts to take on a very human-like form.

Question 43

Period of the fetus

Answer 43

During the period of the fetus, organ systems continue to mature, such as the sex organs, which take a while to develop.

This is why the sex of the baby can’t be determined until the typical 18-week ultrasound.

By this time, the baby’s external genitalia has developed into a penis or a clitoris that could be visible if they are positioned in the right way.

During the fetal period, the lungs also start to mature, the baby begins responding to sound by about the 5th month, and the fetus spends a lot of time growing larger in size and accumulating fat.

This fat will help form myelin coating on the axons of their neurons, which will speed up neural transmission, and it will help them build up a layer of insulation that will be needed to help maintain a constant temperature once they’re born.