Makindo Medical Notes

Related Subjects: |Introduction to Obstetrics and Gynaecology |Female Reproductive Anatomy and Physiology |Basic Concepts of Pregnancy |Health Issues In Pregnancy |Risk assessment In Pregnancy |Anaemia In Pregnancy |Hypertension In Pregnancy |Diabetes In Pregnancy |Epilepsy In Pregnancy |Hyperemesis In Pregnancy |Obesity In Pregnancy |Prescribing in Pregnancy |Multiple Pregnancy |Preterm Labout |Management of Labour and Complications |Assessment of the newborn

Basic Concepts of Pregnancy

• Pregnancy is a physiological process that occurs when a fertilized egg implants and grows in the uterus.
• A full-term pregnancy typically lasts around 40 weeks, divided into three trimesters.
• During pregnancy, the mother’s body undergoes various changes to support the developing fetus.

Stages of Pregnancy

First Trimester (Weeks 1–12)

• The first trimester begins at conception and continues until the end of week 12.
• During this period, the fertilized egg develops into an embryo and then a fetus.
• Key events include:
  • Fertilization and implantation in the uterus.
  • Formation of the placenta, which provides oxygen and nutrients to the fetus.
  • Development of major organs, including the heart, brain, and spinal cord.
• Maternal changes include:
  • Nausea and vomiting (morning sickness), caused by rising levels of human chorionic gonadotropin (hCG).
  • Fatigue, increased urination, and breast tenderness.

Second Trimester (Weeks 13–26)

• The second trimester marks a period of rapid growth for the fetus.
• Key events include:
  • Fetal movements (quickening) are usually first felt by the mother around 18–20 weeks.
  • Development of fine hair (lanugo) and a protective coating (vernix) on the fetus’s skin.
  • Fetal organs, such as the lungs and digestive system, continue to mature.
• Maternal changes include:
  • The uterus expands, and the abdomen becomes noticeably larger.
  • Common discomforts include back pain, swelling of the ankles, and occasional headaches.

Third Trimester (Weeks 27–40)

• The third trimester is the final stage of pregnancy, characterized by the fetus's preparation for birth.
• Key events include:
  • The fetus gains significant weight and its organs, especially the lungs, complete maturation.
  • The fetus assumes a head-down position in preparation for delivery (in most cases).
• Maternal changes include:
  • Increased discomfort due to the growing uterus, including shortness of breath, frequent urination, and difficulty sleeping.
  • In the final weeks, the cervix begins to soften and thin (effacement), preparing for labor.

Key Physiological Changes During Pregnancy

• Pregnancy causes several physiological changes in the mother’s body to support the developing fetus.

Cardiovascular Changes

• Blood volume increases by approximately 30–50% to meet the demands of the growing fetus.
• The heart rate increases, and the cardiac output rises by up to 40%.

Respiratory Changes

• The diaphragm is pushed upwards by the growing uterus, reducing lung capacity.
• Despite this, the respiratory rate remains stable, and oxygen consumption increases to support fetal growth.

Gastrointestinal Changes

• The digestive system slows down due to hormonal changes, which can lead to constipation.
• Heartburn and nausea are common as the growing uterus puts pressure on the stomach.

Hormonal Changes

• Pregnancy hormones, particularly estrogen, progesterone, and hCG, regulate the development of the fetus and the mother's body changes.
• These hormones are responsible for maintaining the uterine lining, enlarging the breasts, and preparing the body for childbirth and lactation.

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