Physiological Changes and Management During Pregnancy and Childbirth

Posted on May 30, 2024 in Physical Education

Cardiac Changes in Pregnancy

  • Cardiac output increases by 40% to compensate for the fall in systemic vascular resistance.
  • The heart is physiologically dilated, and myocardial contractility is increased.
  • Blood pressure decreases in the first and second trimesters but increases to non-pregnant levels in the third trimester.

Increased Oxygen Demand in Pregnancy

Minute ventilation increases by 40–50%, mostly due to an increase in tidal volume.

Pelvic Girdle Pain (PGP) vs. Pregnancy Low Back Pain (PLBP)

  • PGP: Pain between the posterior iliac crest and the gluteal fold, particularly in the vicinity of the sacroiliac joints (SIJ). May radiate into the posterior thigh and occur in conjunction with/or separately in the symphysis pubis.
  • PLBP: Dull pain, more pronounced in forward flexion with associated restriction in spine movement. Palpation of the erector spinae muscles exacerbates pain.

Osteoporosis and Pregnancy

Pregnancy and lactation are associated with reversible bone loss, but studies do not support an association between parity and osteoporosis in later life.

Increased Renal Size in Pregnancy

  • Increase in renal size of 1–1.5 cm due to increased renal blood flow.
  • Mechanical compressive forces on the ureters lead to dilation of the kidney, pelvis, and calyceal systems.

Lung Volume Changes in Pregnancy

  • Reduction in functional residual capacity (FRC) and its subcomponents, expiratory reserve volume (ERV) and residual volume (RV).
  • Increases in inspiratory capacity (IC) and tidal volume (VT).

Pelvic Movement in Vaginal Delivery

Nutation: Approximation of the wings of the ilium towards the median plane of the body and a removal of the sciatic tubers; anteroinferior direction of the sacrum base and a posterosuperior movement of the coccyx.

Characterization of Childbirth

Childbirth is characterized by contractions of the myometrial smooth muscle, promoting dilation of the uterine cervix and expulsion of the fetus through mechanisms of adaptation to the birth canal.

Myometrial Stages of Parturition

  1. PHASE 1 | QUIESCENCE: Lack of response to agents that determine uterine contractility.
  2. PHASE 2 | ACTIVATION: Increased response of the uterus to uterotonics, mainly estrogen. Connections between myometrial cells favor muscular electrical synchronization.
  3. PHASE 3 | STIMULATION: Effective uterine contractions for dilation, expulsion, and de-discharge.
  4. PHASE 4 | INVOLUTION: Uterus involution occurs mediated by oxytocin. Continuous uterine contraction appears at the end of this period, maintaining postpartum hemostasis.

Shoulder Dystocia Management

Position: On all fours or Gaskin position. Facilitates biacromial detachment in shoulder dystocia (Gaskin’s maneuver).

Perineal Massage

  • Purpose: Prevention of perineal trauma.
  • Timing: After 35 weeks of gestational age.
  • Method: Insert one to two lubricated fingers approximately 3 to 4 cm into the vagina, applying pressure to the side and downwards, in the direction of perineal stretching.

Physical Activity in Pregnancy

Exercise can help prevent pregnancy-related disorders, such as GDM, GH, and PE, as well as conditions that impact maternal quality of life, such as anxiety, prenatal depression, LP, and UI. Exercise is not associated with an increased risk of miscarriage, CA, PTB, PM, or inadequate fetal growth. Most benefits can be achieved with compliance to current international guidelines. Exercise intensity should be adapted to women’s previous fitness level.

Pelvic Floor Muscle Training After Delivery

Due to soreness and lack of sensation, start with an experimental slow squeeze following delivery. Gradually progress as you feel comfortable. Resuming pelvic floor exercises as soon as possible after giving birth will help reduce swelling and speed up the healing process.

Transversus Abdominis After Delivery

Purpose: Support your abdomen, back, and pelvis.

Method: Lie on your side, hands just below your belly button on either side of your tummy. Let your tummy sag, then gently breathe in. As you breathe out, draw your lower tummy in towards your back away from your hands, as if you were pulling up a zipper on your trousers. Aim to hold for 3 seconds and progress to 10. You should be able to breathe and talk while doing this exercise. Start with 4-5 repetitions and increase repetitions gradually to 10. Ensure you are not holding your breath during the exercise.