1-2 Anatomy and Physiology of Pregnancy

PREGNANCY TIMELINE

• Antepartum: Time between conception and onset of labor; also known as prenatal.
• Intrapartum: Time between onset of labor and birth.
• Postpartum: Time from birth until the woman's body returns to pre-pregnant state (approximately 6 weeks).

IMPORTANT DATES

• EDC (Estimated Date of Confinement): 40 weeks from the first day of the Last Normal Menstrual Period (LNMP).
• EDD (Estimated Date of Delivery): Same as EDC.
• EDB (Estimated Date of Birth): Same as EDC.
• LMP (Last Menstrual Period): Last period before conception.
• LNMP (Last Normal Menstrual Period): Last normal period before pregnancy.

OB VOCABULARY

• Gravidity and Parity: Essential terms to know.
  • Gravida: Number of pregnancies.
  • Para: Number of deliveries.
  • Nulligravida: Never been pregnant.
  • Nullipara: No births after 20 weeks gestation.
  • Multigravida: Two or more pregnancies.
  • Multipara: Two or more births after 20 weeks gestation.
  • Grand multigravida: More than 5 pregnancies.
  • Grand multipara: More than 5 births at 20 weeks gestation.
  • Great grand multigravida: More than 10 pregnancies.
  • Great grand multipara: More than 10 births at 20 weeks gestation.

GTPAL

• Shorthand: G's (Gravida) & P's (Para).
• Full Version: GTPAL
  • G: Gravida (Number of pregnancies)
  • T: Term (Number of pregnancies delivered at > 37 weeks)
  • P: Preterm (Delivered from 20 weeks to 36 weeks 6 days)
  • A: Abortion (Any pregnancy <20 weeks)
  • L: Living children at the time history is taken.

MULTIPLE GESTATIONS

• Multiple gestations (twins, triplets) count as one pregnancy and one delivery.
  • Example: For someone who delivered twins, the GTPAL would show 1 pregnancy, regardless of the number of babies.

EXAMPLE OF GTPAL

Evaluate the history of Shannon:

• 1st pregnancy: Twins delivered at 32 weeks (alive)
• 2nd pregnancy: Son delivered at 38 weeks (expired at 3 months due to SIDS)
• 3rd pregnancy: Stillbirth at 40 weeks
• 4th pregnancy: Miscarriage at 12 weeks
• GTPAL for Shannon: G=5, T=2, P=1, A=1, L=2 (5-2-1-1-2 written as GTPAL).

NAGELE’S RULE

• Calculate due date using LNMP:
  • Subtract 3 months, add 7 days, adjust the year if needed.
  • Example:
  • LNMP: July 20th
  • Calculation:
    • July 20 - 3 months = April 20th
    • April 20 + 7 days = April 27th

SIGNS OF PREGNANCY

• Subjective (Presumptive): Symptoms felt by the mother.
• Objective (Probable): Signs noted by the provider but could indicate other issues.
• Diagnostic (Positive): Definitive signs of pregnancy.
  • hCG Levels:
  • Increase in levels usually doubles every 48-72 hours for the first 60 days.
  • Abnormal high: multiple gestations or abnormalities; low: impending miscarriage or ectopic pregnancy.

CLASSIFICATION OF PREGNANCY SIGNS

• Presumptive Signs:
  • Amenorrhea, fatigue, breast tenderness, nausea, frequent urination.
• Probable Signs:
  • Positive home pregnancy test, fetal movement felt by provider, Goodell’s sign, Chadwick’s sign.
• Positive Signs:
  • Fetal heartbeat detected, delivery of the fetus.

CHANGES IN PREGNANCY

ENDOCRINE CHANGES

• Hormones of pregnancy: Vital for maintaining pregnancy.
  • hCG: Produced by the placenta; essential for maintaining progesterone and estrogen production.
  • hPL (Human Placental Lactogen): Regulates metabolism, decreases maternal insulin sensitivity; contributes to gestational diabetes.
  • Estrogen: Stimulates uterine growth and breast development.
  • Progesterone: Maintains pregnancy by promoting uterine lining thickening and inhibiting contractions.

RESPIRATORY CHANGES

• Increased oxygen consumption (15-20%) starting from 16 weeks.
• Slight increase in respiratory rate due to pressure from expanding uterus.
• Nasal congestion and nosebleeds common due to vascular congestion.
• State of partially compensated respiratory alkalosis.

CARDIOVASCULAR CHANGES

• Heart position shifts upwards and leftward; increased heart rate (25%).
• Blood volume increases (up to 50% by the 32nd week).
• Decreased blood pressure due to vessel vasodilation.

GASTROINTESTINAL CHANGES

• Relaxation of stomach smooth muscles leads to changes in motility—common cause of morning sickness.
• Increased risk of constipation and heartburn due to slowed gastric emptying.
• Educate on dietary management to prevent discomfort.

RENAL/URINARY CHANGES

• Increased urinary frequency due to pressure from the growing uterus, especially in first and third trimesters.
• Risk of urinary tract infections increases due to anatomical changes.

INTEGUMENTARY CHANGES

• Increased pigmentation and vascular changes; appearance of stretch marks (striae).
• Increased hair and nail growth due to hormonal influence.

FEMALES' MUSCULOSKELETAL CHANGES

• Center of gravity shifts due to increased breast size and abdominal growth, leading to increased risk of falls.
• Changes in hip joint stability and spinal curvature occur.

IMMUNE CHANGES

• Increased white blood cell count helps combat infections.
• Changes in immune response can affect chronic conditions.

PROPER CARE AND MANAGEMENT

• Increase fluid intake, follow dietary guidelines, and be aware of body changes during pregnancy.
• Regular prenatal check-ups are crucial to monitor both maternal and fetal well-being.

SUMMARY

• Pregnancy encompasses significant physiological, hormonal, and anatomical changes to support both the mother and developing fetus. Understanding these changes is vital for providing appropriate prenatal care and education.
• Knowing terminologies like Gravida, Para, and using tools like GTPAL helps healthcare providers to communicate effectively about patient pregnancies.