Physiology and Care in the Puerperium

Chapter 24 Physiology and Care in the Puerperium



Defining the puerperium and the postnatal period


Following the birth of the baby and expulsion of the placenta, the mother enters a period of physical and psychological recuperation. From a medical and physiological viewpoint this period, called the puerperium, starts immediately after delivery of the placenta and membranes and continues for 6 weeks.



Midwives and the management of postpartum care


The postnatal period means the period after the end of labour during which the attendance of a midwife upon the woman and baby is required, being not less than 10 days and for a longer period if the midwife considers it necessary (Nursing and Midwifery Council (NMC) Rule).



Physiological observations



The uterus and vaginal fluid loss


After the birth, oxytocin is secreted from the posterior pituitary gland to act upon the uterine muscle and assist separation of the placenta. Following expulsion of the placenta, the uterine cavity collapses inwards; the now-opposed walls of the uterus compress the newly exposed placental site and effectively seal the exposed ends of the major blood vessels. The muscle layers of the myometrium are said to simulate the action of ligatures that compress the large sinuses of the blood vessels exposed by placental separation. These occlude the exposed ends of the large blood vessels and contribute further to reducing blood loss. In addition, vasoconstriction in the overall blood supply to the uterus results in the tissues being denied their previous blood supply; deoxygenation and a state of ischaemia arise. Through the process of autolysis, autodigestion of the ischaemic muscle fibres by proteolytic enzymes occurs, resulting in an overall reduction in their size. There is phagocytic action of polymorphs and macrophages in the blood and lymphatic systems upon the waste products of autolysis, which are then excreted via the renal system in the urine. Coagulation takes place through platelet aggregation and the release of thromboplastin and fibrin.


Renewal of the uterine lining and renewal of the placental site involve different physiological processes. What remains of the inner surface of the uterine lining, apart from the placental site, regenerates rapidly to produce a covering of epithelium. Partial coverage is said to have occurred within 7–10 days of the birth; total coverage is complete by the 21st day.


Once the placenta is expelled, the circulating levels of oestrogen, progesterone, human chorionic gonadotrophin and human placental lactogen are reduced. This leads to further physiological changes in muscle and connective tissues, as well as having a major influence on the secretion of prolactin from the anterior pituitary gland.


Once empty, the uterus can be likened to an empty sac, although it retains its muscular structure. It is therefore important to remember that the uterus, although at this point markedly reduced in size, still retains the potential to be a much larger cavity. This underpins the requirement to undertake immediate and then regular observations of fundal height and the degree of uterine contraction in the first few hours after the birth. Abdominal palpation of the uterus is usually performed soon after placental expulsion to ensure that the physiological processes described above are beginning to take place. On abdominal palpation, the fundus of the uterus should be located centrally, at the same level or slightly below the umbilicus, and should be in a state of contraction, feeling firm under the palpating hand. The woman may experience some uterine or abdominal discomfort, especially where uterotonic drugs have been administered to augment the physiological process.


The physiological process of the uterus returning to its non-pregnant state is known as involution. A well-contracted uterus will gradually reduce in size until it is no longer palpable above the symphysis pubis. The rate at which this occurs and the duration of time taken have been demonstrated to be highly individual. The uterus should not be tender during this process, although the woman may be experiencing afterpains.


The observations obtained by the midwife about the state of involution of the uterus should be placed into context alongside the colour, amount and duration of the woman’s vaginal fluid loss and her general state of health at that time.



Postpartum vaginal fluid loss (lochia)


Blood products constitute the major part of the vaginal loss immediately after the birth of the baby and expulsion of the placenta. As involution progresses, the vaginal loss reflects this and changes from a predominantly fresh blood loss to one that contains stale blood products, lanugo, vernix and other debris from the unwanted products of the conception. This loss varies from woman to woman, being lighter or darker in colour, but for any woman the shade and density tend to be consistent.



Assessment of vaginal blood loss


The mother should be asked about the current vaginal loss:



image Whether this is more or less than previously.


image Whether it is lighter or darker than previously.


image Whether she herself has any concerns about it.

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Related posts:

  1. The Placenta
  2. Trauma During Birth, Haemorrhage and Convulsions
  3. Obstetric Emergencies
  4. Problems of Pregnancy

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Jul 11, 2016 | Posted by in MIDWIFERY | Comments Off on Physiology and Care in the Puerperium

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