Transcript Bio 27 October 17

Bio 27 November 14, 2012
Chapter 11:
Conception,
Pregnancy, and
Childbirth
SPONTANEOUS AND ELECTIVE
ABORTION
Miscarriage and stillbirth
• A spontaneous abortion happening in the first
20 weeks of pregnancy is a miscarriage; one
happening in the last 20 weeks is a stillbirth
• Early miscarriages may occur before a woman
even knows she is pregnant
• Having one miscarriage does not raise chances
of having additional ones, but multiple
miscarriages can be indicative of problems
Most common causes of miscarriage:
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Chromosomal abnormality
Maternal age >35 years
More than 5 alcoholic drinks per week
More than 375 mg caffeine per day (2–3 cups coffee)
Cocaine use
Damaged cervix
Chronic kidney inflammation
Abnormal uterus
Infection
Underactive thyroid gland
Autoimmune reaction
Diabetes
Emotional shock
Aspirin and ibuprofen use in early pregnancy
Obesity
Elective abortion
• Every year, 3 million American women have unplanned
pregnancies
• In 2005, 1.2 million abortions in the U.S.
• 50% of U.S. women have an abortion by age 45
• 2/3 of women who have abortions in the U.S. say it is
primarily for financial reasons
• 60% of abortions occur in families with an income of
less than $28,000/year for a family of 3
• Despite relatively restrictive laws, U.S. has one of the
highest rates of abortion among developed countries
– This is largely attributed to low rates of sex education and
lack of access to affordable contraceptives
Utilitarian vs. Deontological ethics
• Utilitarian approach: something is good if it is
useful, and an action is moral if it maximizes
pleasure among humans. “The greatest good
for the greatest number”
• Deontological approach: certain moral
principles must guide our actions
1. The scarce drug case
You are an emergency room physician, and you
only have five doses of a certain drug left. Alas,
you have six patients who need it. Bloggs has a
very severe version of the condition for which
the drug is a treatment, and it will take all five
doses of the drug to cure him. Your other five
patients have mild versions of the condition, and
each of them will be cured by a single dose. Any
one of the six who doesn’t get the full dosage
they need will die.
2. The transplant case
Suppose that you are a famous transplant surgeon, and
that your transplants always work. You have five patients,
each of whom needs a transplant. One needs a heart, one
a brain, two need one lung apiece, and one needs a liver.
One of your patients, Bloggs, has come in today to find
out the results from some lab work. You know from the
results of the lab work that Bloggs would be a perfect
donor for each of your five other patients, and you know
that there are no other available donors. So you ask
Bloggs if he would be willing to be cut up and have his
organs distributed. He declines your kind offer, but you
realize that you could easily overpower Bloggs and cut
him up without his consent.
3. The trolley case
The driver of a trolley has passed out at the wheel,
and his trolley is hurtling out of control down the
track. Straight ahead on the track are five men who
will be killed if the trolley reaches them. You are a
passerby, who happens to be standing by the track
next to a switch. If you throw the switch, you will
turn the trolley onto a spur of track on the right,
thereby saving the five. But Bloggs is on that spur of
track on the right; and he will be killed if you turn
the trolley.
Procedures for abortion: medical abortion
• In the U.S., 89% of abortions
are performed in the first 12
weeks of pregnancy
• Risk of dying from a surgical
abortion is 0.1 per 100,000
women (risk of dying from
pregnancy is 11.8 deaths per
100,000 women
• Medical abortion uses a pill,
RU-486, to end pregnancy
– Available in Europe for 20 years
before legalized here in 2000
– Account for 13% of all
abortions in the U.S. currently
– 99% effective in ending
pregnancy before 7 weeks, and
91% effective in the 8th week
Procedures for abortion: suction
curettage
• Used in weeks 7–13 of
pregnancy
• Performed at a clinic or
hospital under local
anesthesia and takes ~10
minutes
• Plastic tube is inserted into
the uterus through the
cervix
• A vacuum aspirator sucks
out the placenta, uterine
lining, and fetal tissue
• No effect on future fertility
Most abortions occur early in
pregnancy
Procedures for later abortion: dilation
and evacuation (D & E)
• Used for pregnancy termination between 13
and 21 weeks
• Usually requires general anesthesia
• Uses suction and scraping of the uterus to
expel the fetus and uterine lining
• 8.9 women per 100,000 die from a 20-week
D& E (still lower than risk of death from
pregnancy)
Late-term abortion
• Late-term abortion: abortion performed after
20 weeks gestation
• Only legal when there are health risks to the
mother or severe fetal abnormalities
• Typically done by dilation and evacuation
Illegal abortions
• 20 million illegal abortions are performed worldwide
each year
• 97% of these are performed in developing nations
where abortion is illegal
• Result in deaths, infertility, and serious health
problems
• Abortion may be attempted by drinking poisons or
inserting them into the vagina or by inserting a sharp
object such as a coat hanger or stick through the cervix
into the uterus
• Countries where abortion is illegal have higher rates of
abortion
Roe v. Wade
• 1973 Supreme Court
decision prevented states
from passing laws making
abortion a crime for
women or their doctors
• Abortion access is still
restricted, primarily
through lack of doctors
that perform it, or lack of
funding for poor women
seeking abortion
The anti-abortion movement
• “Pro choice” and “pro life”
activists are at odds
• Pro-life advocates believe
that life begins at
conception and that a
fertilized egg has the same
rights as any other person
• Some pro-life advocates
have committed violent
acts at abortion clinics
– May 2009: Dr. George Tiller
was shot and killed at his
church
Reducing the rate of abortion
• Many steps can be taken to reduce the incidence
of abortion:
– Preventing unwanted pregnancy through increased
access to contraceptives
– Improving sex education, not relying on “abstinenceonly” education
– Providing resources to facilitate adoption
– Providing financial assistance to low-income families
with children
• Politicians who advocate for restrictions on
abortion also tend to advocate against these
things
THE EXPERIENCE OF PREGNANCY
The woman’s experience
• A study of 1000 women found that:
– 35% loved being pregnant
– 40% had mixed feelings about it
– 8% hated it
– others had different experiences with different
pregnancies
• 20% of women experience significant
depression during pregnancy
The man’s experience
• Men do not physically experience pregnancy,
but may gain “sympathy weight”
• Pregnancy can be a time of excitement, but
also anxiety for expectant fathers
• Some fathers can feel excluded by the fact
that they do not experience the physical
changes of pregnancy
Sexual interaction is OK during
pregnancy
• Regular intercourse and orgasm are associated
with a LOWER risk of preterm birth
• First trimester: nausea, breast tenderness, and
fatigue can make a woman less sexually
responsive
• Second trimester: usually a reprieve
• Third trimester: physical discomfort and
feelings of physical unattractiveness may
reduce a woman’s desire
HEALTHY PREGNANCY
First trimester (0–13 weeks)
• Sperm and egg unite to form
a zygote in the fallopian
tubes
• The zygote divides to form a
blastocyst that implants in
the uterine wall after about 1
week
• By 9–10 weeks after the last
menstrual period, the fetal
heartbeat can be heard with
a special instrument
• Fetus is about 3 inches long
by the end of the 13th week
Second trimester (14–26 weeks)
• Sex of the fetus can be
determined, although can
be difficult to see clearly
before 19–20 weeks
• Fingernails, eyebrows, and
eyelashes are clearly
formed
• Fetus is covered by fine
hair that is typically, but
not always, lost by birth
• By 22 weeks or so, fetus
typically weighs about 1
pound
Third trimester (27–40 weeks)
• Last two months of
gestation are a period
of rapid weight gain
• Lungs and brain mature
• Most babies born at any
point during the third
trimester will survive
Prenatal care
• Infant mortality in the
U.S. is high; largely
attributed to worse
prenatal care
• Low-income women are
less likely to receive
adequate prenatal care
• Low-income women are
also more likely to die in
childbirth
Fetal development
Risks to fetal development
• Fetuses depend on maternal nutrition; adequate folic
acid is particularly important; prenatal vitamins contain
this
• Recommended BEFORE you get pregnant as especially
important in first weeks of pregnancy
• Alcohol crosses the placenta and can cause fetal
alcohol syndrome, esp. with binge drinking (5 or more
drinks)
• Fetal alcohol syndrome can cause spontaneous
abortion, low birth weight, brain damage and physical
malformation
• Many other drugs can also be harmful to fetuses
Homework assignment
• Due at THE BEGINNING of class on November
19th
• Write (in 300–500 words) about your feelings
about assisted reproductive technology (in
vitro fertilization). Are there any aspects of
this technology that make you
uncomfortable?