HESI Maternity Study Guide
Anatomy and Physiology of Reproduction
The Menstrual Cycle
❖ Mean age for menarche is 12.87, or 1 to 3 years after breast
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Phases of the Menstrual Cycle
❖ Menstrual phase: Days 1 to 5 of cycle
➢ Shedding occurs in form of bleeding
❖ Proliferative (follicular) phase: Day 5 to ovulation
➢ “Preovulatory phase”
➢ Begins the first day of menstruation and ends 14 days after
➢ FSH is secreted
➢ Surge of LH converts the follicle to a corpus luteum, which produces progesterone
❖ Ovulatory phase:
➢ Mature follicle ruptures and the ovum is released from the ovary
➢ Ovum is picked up and transported to uterus
❖ Luteal phase: immediately after ovulation and ends with menstruation
➢ Fertilized ovum is implanted in the endometrium
➢ In the absence of implantation, the corpus luteum regresses, estrogen and progesterone levels decrease, and the endometrium is shed
❖ Endometrial cycle:
➢ Menstrual phase: periodic vasoconstriction in endometrium initiates shedding of ⅔ of endometrium
■ Varies in length in most women
➢ Proliferative phase: depends on estrogen
➢ Secretory phase: includes the day of ovulation to 3 days prior to next menstrual period
➢ Ischemia phase:
■ Blood supply to the functional endometrium is blocked and necrosis occurs
■ Functional layer separates from basal layer and menstruation begins
HESI HINT: Ovulation occurs approximately 14 days before the next menstrual cycle
HESI HINT: To avoid pregnancy a woman should abstain from unprotected sex during her fertile days. The most fertile days for pregnancy are the day before ovulation and the day of ovulation. The fertile period begins 4-5 days prior to ovulation and ends 24-48 hours after ovulation. A couple must avoid unprotected sex for several days before an anticipated ovulation and for 3 days after ovulation to prevent pregnancy because sperm can live in a woman's body approximately 4-5 days and eggs lives approximately 24-48 hours after being released.
Fertilization
● Indications of ovulation
○ Slight drop in temp occurs a day before
■ Temp remains elevated for ~10-12 days
○ Preovulatory and postovulatory mucus is thick
■ To discourage sperm penetration
○ At ovulation cervical mucus is abundant, watery, thin, clear
■ Spinnabarkeit - looks, feels and stretches like an egg white
○ Cervical os dilates slightly, softens, and rises in the vagina
○ Some women have localized abdominal pain = mittelschmerz
○ Ferning is seen under microscope
● Conditions for fertilization
○ Fallopian tubes are patent
○ Adequate progesterone and secretory endometrium
○ Semen is supportive to pregnancy: 2 ml semen
● Implantation
○ Fertilization takes place in ampulla (outer third) section of Fallopian tube
○ Zygote takes 3-4 days to enter uterus
○ Takes 7-10 days to complete implantation process
● Fetal development
○ Zygote: 12-14 days after fertilization
■ From time the odium is fertilized until it is implanted in the uterus
○ Embryo: 3-8 weeks after fertilization
■ Most vulnerable to teratogens
○ Fetus: 9 weeks after fertilization to term
■ Fewer major anomalies
Maternal Physiologic Changes during Pregnancy
● Pregnancy length: first day of LMP to 40 weeks
○ 280 days, 10 lunar months, 9 calendar months
● Divided into three 13-week trimesters
HESI HINT: Some women do not realize they are pregnant because they experience implantation bleeding or spotting
Fetal and Maternal Changes
8 Weeks
● Fetal Development:
○ Rapid; major divisions of brain are observable
○ Heart begins to pump blood
○ Weight is 2 g
● Maternal Changes:
○ Nausea for up to 12 weeks
○ Hegar sign - softening of the isthmus of cervix
○ Goodell sign - softening of the cervix
○ Chadwick sign - bluing of vagina
○ Leukorrhea increases
● Nursing Interventions
○ Avoid hot tubs, saunas, and steam rooms - increases risk for NTD in first trimester
12 Weeks
● Fetal Development:
○ Heart is observable
○ Sex is determinable
○ Fetus weighs 2-4 lbs
● Maternal Changes:
○ Uterus rises to pelvic brim
○ Braxton Hicks contractions are possible
○ Weight gain is 2-4 lb (total) during first trimester
○ Fully functional placenta
● Nursing Interventions:
○ Teach prevention of UTI
■ Fluid intake - 3L/day
■ Void frequently - q2hrs
○ Increase caloric intake by 300 calories per day
16 Weeks
● Fetal Development:
○ Arm/leg ratio is proportionate
○ Muscular movements detected
○ General sense organs differentiated
○ Testes in position for descent or vagina open
● Maternal Changes:
○ Quickening may be noted between 16-20 weeks
○ Colostrum may be expressed from the nipples this early
○ Insulin resistance begins as early as 14-16 weeks and continues to rise until it stabilizes during the last few weeks of pregnancy
○ Weight gain of 1 lb per week beginning in second trimester
● Nursing Interventions:
○ MSAFP and screening test between 15-22 weeks, ideally 16-18 weeks
■ Elevated levels = open NTD and multiple gestations
■ Low levels - Down syndrome
● Abnormal levels are followed by US
○ Explain multiple-marker blood test and get a blood specimen between 16-18 weeks to measure MSAFP, hCG, and unconjugated estriol
20 Weeks
● Fetal Development:
○ Vernix and lanugo present
○ Fetus sleeps, sucks and kicks
○ Fetus weighs 200-400 g
● Maternal Changes:
○ Fundus reaches level of umbilicus
○ Areolae darken
○ Pregnancy becomes “real”
○ Leg cramps begin
● Nursing Interventions:
○ Teach comfort measures
■ Remain active
■ Sit with feet elevated [Show Less]