Maternal Baby Quiz: Fetal Growth Terms

Terms Indicating Fetal Development

• Ovum: Stage from ovulation up to fertilization.
• Zygote: Stage from fertilization until implantation in the uterus.
• Embryo: Stage from implantation until 5-8 weeks gestational age.
• Fetus: Stage from 5-8 weeks until full term.
• Conceptus: Refers to the developing embryo or fetus and associated placental structures throughout the duration of pregnancy.
• Age of Viability: Generally recognized as 24 weeks; this is when the fetus has a chance of survival if born, typically weighing over 400 g.

Key Developmental Milestones

• End of 4th Gestational Week:

  • Length: ~0.75 cm; Weight: ~400 mg.
  • Formation of spinal cord; head represents one-third of embryo.
  • Rudimentary heart and limb buds are developing.

• End of 8th Gestational Week:

  • Length: ~2.5 cm; Weight: ~20 g.
  • Completion of organogenesis; heart has septum and valves, beats rhythmically.
  • Facial features and limbs are identifiable; external genitalia developing.

• End of 12th Gestational Week:

  • Length: 7-8 cm; Weight: ~45 g.
  • Nail beds forming; presence of spontaneous movements and reflexes.
  • Sex differentiation observable externally; urine secretion begins.

• End of 16th Gestational Week:

  • Length: 10-17 cm; Weight: 55-120 g.
  • Fetal heart sounds detectable; lanugo present.
  • Liver and pancreas functioning; sex identifiable through ultrasound.

• End of 20th Gestational Week:

  • Length: 25 cm; Weight: 223 g.
  • Active fetal movements felt by mother; antibody production starts.
  • Meconium present in the intestines; brown fat formation begins.

• End of 24th Gestational Week:

  • Length: 28-36 cm; Weight: 550 g.
  • Lung surfactant production begins; eyelids open, responding to light.
  • Age of viability achieved; notable fetal reactions to sound.

• End of 28th Gestational Week:

  • Length: 35-38 cm; Weight: 1,200 g.
  • Nearly mature lung alveoli; testes descend.
  • Risk of retinal damage due to high oxygen from preterm care.

• End of 32nd Gestational Week:

  • Length: 38-43 cm; Weight: 1,600 g.
  • Subcutaneous fat deposits increase; responses to sounds observed.
  • Iron stores accumulating for post-birth nutrition.

• End of 36th Gestational Week:

  • Length: 42-48 cm; Weight: 1,500-2,700 g.
  • Formation of body stores and reduction in lanugo.
  • Fetus usually turns head down, preparing for delivery.

• End of 40th Gestational Week:

  • Length: 48-52 cm; Weight: ~3,000 g.
  • Active fetal movement; hemoglobin transition begins.
  • Fingernails extend beyond fingertips; creases on soles of feet become apparent.

Assessment Methods in Pregnancy

• McDonald's Rule: Measure fundal height in cm to estimate gestational age (Ht in cm x 2/7 = months; x 8/7 = weeks).
• Doppler Technology: Utilized to monitor fetal heart rate.
• Signs of Pregnancy:
  • Presumptive Signs: Least indicative; could relate to other conditions.
  • Probable Signs: Objective and documentable by an examiner.
  • Positive Signs: Confirmation through fetal heartbeat detection, movements observed, or ultrasound visualization.

Determining Estimated Due Date (EDD)

• Naegel's Rule:
  • LMP between April-Dec: Subtract 3 months, add 7 days, and 1 year.
  • LMP between Jan-Mar: Add 7 days, then 9 months.

Estimating Gestational Age (AOG)

• Date of Quickening:
  • Primigravida: Date + 4 months + 20 days.
  • Multigravida: Date + 5 months + 4 days.

Fetal Weight Estimation

• Estimated using crown-to-rump length in cm: CRL (cm) x 100 = weight (g).

Pregnancy Status Classification

• Gravida: Refers to a woman who is/has been pregnant.
• Para: Number of pregnancies reaching viability, regardless of live birth.
• Primigravida: First-time pregnancy.
• Primipara: First birth past viability.
• Multigravida: Previous pregnancies.
• Multipara: Two or more viable pregnancies.
• Nulligravida: Never been pregnant.

GTPALM Classification

• T: Term births (≥37 weeks).
• P: Preterm births (<37 weeks).
• A: Abortions (spontaneous or therapeutic).
• L: Living children.
• M: Multiple pregnancies.