unit 2 - anthro 3621

general depression rates in women

approximately 12% of all women experience depression in a given year

• 25% for low-income women

• 5-25% for pregnant, postpartum, and parenting women

• 40-60% for low-income mothers

prenatal depression

affects 10-20% of pregnant mothers

presents as: crying, fatigue, appetite disturbance, loss of pleasure, guilt anxiety, irritability, and poor fetal attachment

how does untreated depression affect pregnancy?

can lead to…

• low birth weight and size of infants

• higher rates of miscarriage, preterm labor, placental abruption, and preeclampsia

• irritable babies

• lack of adequate prenatal care

• higher use of alcohol and drugs

• postpartum depression

• suicide

antidepressants and pregnancy

pregnancy puts women with a history of depression at a higher risk for recurrence

pregnant individuals on antidepressants should be aware of the risk of relapse and the risk/benefit ratio of continued use

FDA labeling of antidepressants

pregnancy and lactation drugs include

1. risk summaries

2. clinical considerations

3. data sections

“Use the medication in pregnancy when clearly needed” → physician discretion is relied on over medication data

no distinctions are made between human and animal data, and drugs often see delays in updates of new clinical safety reports

antidepressant use during pregnancy

SSRI’s are some of the most commonly used antidepressants (ex: Prozac, Celexa, Lexapro, Zoloft)

research indicates SSRIs can be used during early pregnancy

• absolute risk of SSRI exposure in pregnancy is small

• late-trimester exposure to SSRIs is associated with transient irritability, agitation, jitteriness, and tahcypnea

• SSRIs increase risk of preterm birth by 5 days

• stopping SSRIs during pregnancy is associated with increased rates of spontaneous abortions

benzodiazepine use during pregnancy

anxiety is a risk factor for preeclampsia, preterm labor, low birth weight, PPD, and long-term behavioral, cognitive, developmental, and medical problems in the exposed fetus

benzo use

• evidence for slight increases in oral clefts with first-trimester exposure

• infants may show signs of toxicity if mothers take high doses in late pregnancy

stress from racism and discrimination during pregnancy

contributes to hypertension and pre-eclampsia, which are especially high in African American women

• rates of pre-eclampsia decreased in AA women during Covid

• black women were the only group that saw a decrease

racial myths in healthcare

pervasive racial bias and unequal treatment against Black women in the healthcare system result in inadequate treatment for pain and the dismissal of cultural norms

myth = Black patients have less-sensitive nerve endings and thicker skin than Whites

case study: 2011 nursing textbook

all “facts” about Africa in a 2011 nursing textbook were based on an 1980s ethnography written on research from the 1970s

• only followed one study about one group of people (!Kung/Ju)

• ~13,000-44,000 !Kung/Ju were used to represent the 1.2b people in Africa

• some of the ideas in the book were rejected by the !Kung/Ju people, but still cited as factual

institutionalized racism

structural barriers that act to limit care and increase risks in the health care system

racialized pregnancy stigma in everyday contexts (Mehra et al., 2020)

regardless of SES, participants encountered the assumption that Black pregnant women had low incomes and were dependent on government resources

• Black women were considered welfare queens

  • regardless of age, education, income, insurance coverage, marital status, or number of children

participants were assumed to be single mothers with multiple children

effects of medical racism

minority women of all SES report experiencing medical racism

• effects are associated with preterm birth and contribute to racial disparities for infants

• healthcare providers disproportionately recommend tubal ligation to Black women

• encountering racial stereotypes or prejudice can overshadow good treatment

nonjudgemental interactions lead to more comfort in sharing important health information, which leads to improved prevention, detection, and management

racism and prenatal care graphs and data

prolaction

responsible for breast development and lactation

released by the pituitary

placental lactogen

facilitates placental growth; higher binding affinity for prolactin receptors than maternal prolactin

released from the placenta into maternal circulation

how does prolactin and placental lactogen affect the maternal brain?

leads to cardiovascular and respiratory changes in the mother

leads to altered glucose metabolism of the mother

• insulin resistance in the brain

leads to neurogenesis

increased aggression to protect the young

reduced anxiety and stress response

reduced fever response

mammary gland changes during pregnancy

nonpregnant state = small fat pad, smaller number and size of ducts

pregnant/lactating state = larger nipple and areola size, larger scent glands to orient infants, larger number and size of ducts, increased vascularization, larger alveoli, increased overall size

• before birth, placental lactogen stops milk production

• after birth, prolactin causes lactogenesis

uterine changes during pregnancy

significant increase in blood flow; approaches 500-750cc/minute at term

• involves the uterine venous plexus, uterine veins, uterine artery, vaginal venous plexus, and vaginal arteries

• hemorrhaging can lead to total blood loss within 10 minutes

changes to the blood during pregnancy

slight increase in WBCs

minimal change in platelet count

increased pH, decreased pCO₂, decreased pHCO₃

increased cardiovascular activity (HR, SV, and CO)

changes in pulmonary activity during pregnancy

increased tidal volume (increased lung size and rib cage volume)

decreased expiratory reserve volume and residual volume

increase in O₂ demand —> O₂ is prioritized in the placenta

breathlessness (elevation of diaphragm)

changes to the CNS during pregnancy

increased pituitary size and activity

estrogen and progesterone enter the brain, changing the balance between inhibition and stimulation

decreased oxytocin release

changes to the kidneys during pregnancy

increased renal blood flow; increased size of the kidneys

increased GFR (creatinine clearance)

decreased serum BUN, creatinine, and uric acid

increased urination frequency

• increased risk of UTIs

evolution of pregnancy

mammals can become pregnant and have internal gestation because the mammalian genome has incorporated the syncytin gene

syncytin

a protein produced by placental cells that facilitates trophoblast invasion and transfomration; necessary for placental formation

appears to have originated in viruses

placental classifcation

depends on the number of cellular layers between fetal and maternal blood supplies

hemochorial

found in rodents and primates

3 layers

endotheliochorial

found in dogs and cats

5 layers

epitheliochorial

found in pigs and horses

6 layers

diffuse placenta

uniform distribution of chorionic villi covering the chorion’s surface; found in pigs

cotyledonary placenta

have numerous, discrete, button-like structures called cotyledons that join with the maternal caruncle, forming a placentome; found in ruminants (grazing herbivores)

zonary placenta

have a band-like zone of chorionic villi with both edges acting as exchange zones; found in cats and dogs

discoid placenta

have a regionalized disc-like structure and singular umbilical cord

placentophagy

the practice of eating placentas

common in most non-human animals, even those that don’t eat meat

theories

• hides evidence of birth and blood

• recover nutrients used for the placenta

makes it difficult to study placentas across species

chorionic plate

the fetal side of the placenta

contains fetal blood vessels and is derived from embryonic tissue

covered by smooth and glistening amnion overlaying the chorion

umbilical cord is attached at/near the center

basal plate

the maternal side of the placenta

contains maternal blood vessels and is composed of endometrium (uterine lining)

has a rough and spongy appearance; divided into 15-20 cotyledons

perforated by the spiral arteries, allowing entry of maternal blood into the intervillous space

cellular layers of the placenta

average human placenta

diameter = 22cm

depth = 2-2.5cm

average weight = 613g (varies by country)

placenta weight: baby weight = 1:5.6g

umbilical cord = 50cm x 2cm, central cord insertion

how does umbilical cord length affect the fetus?

too short

• early severing

• constrained fetal movement

too long

• excessive fetal movement

• poor fetal positioning during birth

primate placentas

slightly smaller and lighter than human placentas

typically have longer umbilical cords and non-central insertion

overview of placental function

nutrient exchange (fatty acids, glucose, amino acids, vitamins, minerals)

oxygen exchange

waste exchange

water exchange

hormone release

human placental lactogen (HPL)

hormone produced by the placenta

antagonizes insulin → spares glucose for use by the fetus

enhances lipolysis → provides an alternate fuel source for the mother

human chorionic gonadotropin (hCG)

hormone produced by the placenta

stimulates corpus luteum to secrete estradiol and progesterone

respiratory function of the placenta

although fetal respiratory movement occurs, no active exchange of gases takes place

intake of O₂ and output of CO₂ take place by simple diffusion across the fetal membrane

O₂ delivery to the fetus is at the rate of 8 mL/kg, which is achieved by cord blood flow of 160-320 mL/min

nutritional function of the placenta

fetus obtains its nutrients from the maternal blood

glucose → transferred to the fetus by facilitated diffusion

lipids → transferred across the fetal membrane or synthesized in the fetus

amino acids → transferred by active transport

water and electrolytes → Na, K, Cl cross by simple diffusion; Ca, P, and Fe cross by active transport

water-soluble vitamins → transferred by active transport, but the fat-soluble vitamins are transferred slowly

immunological function of the placenta

fetus is considered a foreign body to the birthing person

aids in successful function

despite foreign paternal inherited antigens in the fetus and placenta, there is no graft rejection due to immunological protection provided by the placenta

placental transfer of immunity (IgG)

umbilical cord

approx 20cm long at full term

contains umbilical veins, arteries, and wharton’s jelly

develops from and contains remnants of the yolk sac and allantois

umbilical vein

brings nutrients from placenta to baby (only one vein)u

umbilical arteries

bring waste back to the placenta (two arteries)

wharton’s jelly

a mucoid connective tissue that fills and serves as vascular support for the umbilical cord

prevents kinking of the vessels during movement of the fetus in the womb

how does the placenta affect maternal arteries

remodels the smooth muscle and endothelium of spiral arteries with syncytiotrophoblast and trophoblast, impacting blood flow and pressure

anterior placenta location

anterior → can interfere with imaging and feeling fetal movement, but does not impact birth

marginal placental location

marginal → within 2cm of the cervical opening; vaginal birth is tried first, C-section if necessary

partial/total placental location

partial/total → placenta blocks the cervix, making C-sections medically necessary

bilobal placental shape

two lobes

battledore placental shape

marginal cord insertion

associated with small size for gestational age, low birth weight, and emergency C-sections

velamentous cord insertion

umbilical cord inserts into the fetal membranes instead of the placental disc

• vessels travel between the amnion and chorion before reaching the placenta

elevated risk of damage to the cord (fetal hemorrhage)

furcate cord insertion

umbilical cord inserts normally into the chorionic plate of placental disc, but the umbilical vessels lose their protective covering of Wharton’s jelly before insertion

elevated risk of damage to the cord (fetal hemorrhage)

interpositional insertion

the umbilical vessels remain protected by Wharton’s jelly as they reach the chorionic plate

very rare, no added risks to fetal development

monochorionic-monoamniotic placenta

occurs with monozygotic twins (identical; share a placenta)

one placenta, one amniotic sac, one chorionic sac, two fetuses

• twins do not get a 50/50 split of the placenta

• each twin has an umbilical cord

monochorionic-diamniotic placenta

typically occurs with monozygotic twins (identical; share a placenta)

one chorionic sac and two amniotic sacs in one placenta

dichorionic-diamniotic placenta

occurs in dizygotic twins (fraternal; two eggs and two sperm)

two placentas, two amniotic sacs, two chorionic sacs

• all independent of each other

• placentas are typically smaller in size

gastrointestinal changes during pregnancy

placental vein makes direct contact with the liver

how is the fetus positioned during birth?

at the onset of labor, the fetal skull is oriented sideways

the skull rotates to avoid bone, flexing as it emerges

the fetus is born looking at the mother’s sacrum (spine side)

contractions

squeezing of the uterus to push the fetus out of the cervix

measured from the start of one contraction to the start of the next contraction

triggered by prostaglandins and oxytocin

become more intense and regular as labor progresses

braxton-hicks contractions

false/non-labor contractions

characterized as uncoordinated, isolated, and less frequent

non-labor inducing

cervical effacement

thinning and shortening of the cervix during labor

cervical dilation

increasing size of the cervix during labor

low amniotic fluid

normal volume = 600-900mL at delivery; mostly fetal urine

low volume can put the fetus at risk for cord compression due to lack of blood flow to the fetus

water breaking

spontaneous rupture of membranes

typically occurs at/during the onset of active labor contractions

artifical rupture can be used to speed up or induce labor

pelvic stations

-5 = not ready for birth

0 = fetus head is at the bottom of the pubic symphysis

+5 = imminent delivery, head has reached the cervix

early stage of labor

gradual dilation and effacement of the cervix

averages 6-12 hours

active stage of labor

increased intensity and frequency of contractions, typically beginning at ~4cm dilation

averages 4-8 hours (for a first pregnancy), but can range from minutes to days

precipitous labors

very short labors (<3 hours)

potential concerns

• increased risk of vaginal tears

• birth can occur anywhere → potentially bad location, may not be someone with sufficient medical knowledge around

timing of birth

historical trend → most births occur closer to midnight

• ancestral form of predator evasion

modern trend → inductions change trends

labor support

support person can be a partner, family member, friend, or trained doula

support for the laboring person has been shown to have positive effects on health and well-being

doula

a trained professional who provides continuous physical, emotional, and informational support to a mother before, during, and shortly after childbirth

• not a nurse or physician (although some may have medical degrees)

• complete training by a national or international accrediting professional board; adhere to professional standards

• typically not covered by insurance in the US

labor induction

stimulation of uterine contractions during pregnancy before labor begins on its own to achieve a vaginal birth

• can be done after 39 weeks

• commonly done for medical reasons

methods:

• prep the cervix using synthetic prostaglandins

• insertion of a catheter & balloon into the cervix

• rupture of the amniotic sac (amniotic fluid is a natural labor inducer)

• use of intravenous medication

misoprostol and labor induction

misoprostol was originally used an ulcer medication, but was found to be very effective at inducing labor

• increases the risk of uterine ruptures if the mother has had past uterine trauma (e.g., C-sections, car accidents, etc.)

bishop scoring system

based on a digital cervical exam of a patient to determine if induction will be successful for vaginal delivery; ranges from 0-13 points

utilizes cervical dilation, position, effacement, consistency of the cervix, and fetal station

higher score = higher likelihood of a successful induction

augmentation

enhancement of contractions in a pregnant woman who is already in labor

cervical ripening

the use of pharmacologic or other means to soften, efface, and/or dialte the cervix

pushing and delivery

begins at full dilation (10cm)

fetus head moves through the vaginal canal and stretches (or tears) the perineum; most infants deliver face down

ends with the delivery of the baby

fetal skull

made of more bones than adult skulls, allowing parts of the fetal skull to slide and compress as it passes through the vagina

compression may lead to bumps and dents at birth, but they quickly recover

contains 6 fontanelle (soft spots)

fontanelle

an area with no bone in the fetal skull; “soft spot”

location of fetal brain scans using ultrasound probes

epidurals

use a combination of medications for local pain relief; causes numbing of (typically) the entire lower body

• epidural needle is inserted into the epidural space (between two vertebrae); typically L3 and L4

• performed between 4-6cm dilation

may alter fetal heart rate, leading to a lower APGAR score

• interferes with fetal breathing and latching

• requires more fetal monitoring

63.4% of US mothers have epidurals

fetal monitoring

fetal monitoring belts are used to track changes in the fetus and mother during pregnancy

• bluetooth options are becoming more popular

can be intermittent or continuous

• intermittent = recommended by manufacturer

• continuous = used for serious complications or when interventions may be necessary, reduced neonatal seizure rate

upright birth position

the historical norm

allows for greater pelvic dimensions and greater ease of delivery

• no sacrum interference

• gravity assistance

typically involves squatting with hanging supports or horizontal support bars

lithotomy birth position

horizontal/semi-upright position

narrows the pelvis inlet by up to 25%

• limited sacrum movement

cord clamping

current recommendations = wait 1-5 minutes (or until pulsing ends) to cut the umbilical cord

allows blood in the placenta to diffuse to the infant

associated with long-term iron levels in the infant

APGAR score

standard physical assessment given to a newborn at 2 minute and 5 minutes after birth to evaluate their overall physical condition and how well they are tolerating the transition to life outside the womb

scored from 0-10

perineum

space between the anal and vaginal opening

perineal tears

rips in the perineum during delivery

• 90% of first-time deliveries involve tears

usually repaired with stitches as part of routine care, but may require surgery

scaled from 1 (lightest) to 4 (most severe)

episiotomy

incisions made in the perineum to enlarge the vaginal opening

performed to prevent, control, or direct tears

assisted vaginal delivery (AVD)

facilitation by forceps or vacuum extraction inserted through the cervix to guide and pull the fetal head during delivery

associated with increased pelbic floor trauma

may include…

• unmedicated labor

• VBAC

• pain management

• episiotomy

vaginal birth after cesarean (VBACs)

individuals who choose to have a vaginal birth after previously having a C-section

• historically believed that people who had C-sections before always need to have C-sections for later births