LEARNING TOPIC
Stages of pregnancy

  updated 13 May 1999 

Keywords
  • gestation
  • antenatal care
  • birth
  • trimester
  • pregnancy physiology
  • human embryology
  • malformation
  • teratogenesis
  • respiratory distress syndrome
  • corticosteroids
  • surfactant
   

Pregnancy is a time of major change both for mother and fetus. From a maternal point of view significant physiological changes occur in all body systems which not only lead to a wide range of symptoms and complaints but when these changes do not follow their normal course may be associated with the development of disease. The fetus undergoes massive developmental changes from conception to delivery. Knowledge of both maternal and fetal development during pregnancy is essential for: 1. Properly understanding and being able to explain and manage normal pregnancy symptoms; 2. Managing pregnancy related illness particularly from the point of view of possible drug effects on mother and fetus and the timing of delivery.

Normal pregnancy

Familiarise yourself with the length of normal pregnancy (gestation) and definitions of miscarriage, birth (livebirth and stillbirth) and methods of describing maternal and perinatal mortality and morbidity (such as perinatal death rate).

Understand the basics of pregnancy care (eg frequency of visits and investigations) and the different types of delivery.

Maternal body system changes

Understand the physiological changes that occur during pregnancy especially those related to the cardiovascular, respiratory, gastrointestinal, haematological and renal systems. Familiarise yourself with the normal ‘symptoms` of pregnancy that occur due to these physiological changes (eg dyspnoea, heartburn, constipation, oedema and frequency).

Embryological development

Understand basic human embryology with the timing in gestation of the development of major organ systems

Familiarise yourself with basic causes of fetal malformation.

Note the Australian Drug Evaluation Committee`s classification of drugs in pregnancy.

Fetal maturation

Understand the timing of basic fetal organ maturation (in particular the respiratory system) and its importance in timing of delivery and possible therapies used to help accelerate this maturation (eg corticosteroids).

Recommended and Optional Readings and Resources

See reading list

Author/s:   Dr Michael Peek, Dept of Obstetrics and Gynaecology, Canberra