BIOL80A Final | Pregnancy

what is pregnancy?

a period when a fetus (or more) grows inside the uterus

when does pregnancy begin?

with fertilization of an egg by sperm (forming the zygote —> embryo —> fetus)

How long is pregnancy measured, and from what point?

~280 days / 40 weeks, measured from the last menstrual period (LMP)

What are the embryo and fetus timeframes?

Embryo: weeks 3–8; Fetus: week 8–birth.

What happens to the zygote after fertilization?

It travels through the fallopian tube to the uterus and must implant within ~7 days.

What happens if the embryo does not implant within ~7 days?

 It deteriorates and dies.

what is implantation?

when the outer layers of the blastocyst grow into the endometrium, enclosing it

Which blastocyst layer releases hCG?

The chorion.

What hormone does the chorion release?

Human chorionic gonadotropin (hCG).

What does hCG do?

Maintains the corpus luteum so it continues secreting progesterone.

what is progesterone?

hormone crucial for maintaining the endometrium to support the embryo

What do pregnancy tests detect?

β-hCG in urine (or blood), detectable even before a missed period.

Why is LMP used to estimate due date?

 It’s easier to remember and assumes conception ~day 14 of the cycle.

when is the first trimester?

weeks 0-12

when is the second trimester?

weeks 13-26

when is the third trimester?

weeks 27-40

when does the placenta take over estrogen and progesterone production?

in the 2nd trimester

How much do estrogen and progesterone levels increase during pregnancy?

About 30-fold by childbirth.

What is assessed at the first prenatal appointment?

Medical history, due date, physical exam.

What lab tests are done at the first prenatal visit?

Blood type, anemia, immunity/vaccine status, tests for hepatitis B, syphilis, gonorrhea, chlamydia, HIV; urine test for pregnancy, UTI, kidney function.

What topics are discussed in early prenatal care?

Genetic screening, nutrition, prenatal vitamins, exercise, substance use, intercourse, vaccinations, travel.

What imaging may occur during first prenatal visit?

Ultrasound or Doppler to hear fetal heartbeat.

How often are prenatal visits from weeks 4–28?

Once a month.

How often from weeks 28–36?

Every other week.

How often from week 36 until birth?

Every week

What proportion of U.S. infants in 2023 were born to women with late/no prenatal care?

About 1 in 14 (7%).

what are some financial barriers to prenatal care?

cost of prenatal care, delivery, and related services

what are some structural barriers to prenatal care?

long wait times, lack of provider continuity, limited Medicaid-accepting providers

what are some transportation barriers?

travel distance, transportation cost, limited public transit

what are some childcare barriers to prenatal care?

lack of childcare for other children

what are some personal barriers to prenatal care?

negative attitudes, mental health issues, lack of pregnancy awareness

wha are some community barriers to prenatal care?

stigma, fear, lack of social support

what are some health care system barriers to prenatal care?

language barriers, clinic-level delays