Reproductive Physiology 3

Please review the expanded lecture notes on gestation

Responses of mother’s body to pregnancy

weight gain

Source	Weight gain
fetus	4 kg
extrafetal material	2 kg
uterus	1 kg
breasts	1 kg
blood and ECF	3 kg
miscellaneous	2 kg

metabolism

nutrition

iron

vitamin D

changes in maternal circulation

blood flow through placenta and cardiac output

blood volume

respiration

minute ventilation

respiratory rate

urinary system

amniotic fluid and its formation

preeclampsia of pregnancy

Of the most serious complications of pregnancy, preeclampsia is the commonest. In the widest sense of the term, it probably occurs in about 10% of all pregnancies; in the most severe form, about 2%. There are no known predictors, preventative methods, or treatment for preeclampsia. Those most at risk are those women with a previous or family history of preeclampsia, those suffering from elevated blood pressure or kidney disease, those over 40 years of age, those with a BMI > 35, and first-time mothers. In the early stages, the patient is asymptomatic; later, it exhibits high blood pressure, proteinuria, and often edema in mother, and sometimes poor growth in the fetus. About 3–10% of preeclamptic patients develop eclampsia.

eclampsia

Eclampsia, one or more convulsions occurring during or immediately after pregnancy as a complication of preeclampsia, can occur at any stage during the second half of the pregnancy (some rare occurrences have been reported before 20 weeks gestation). An eclamptic convulsion looks just like an epileptic seizure; there are of the characteristic spastic contractions of muscle groups in the head, neck, and limbs. Most convulsions last no longer than a minute, but sometimes they continue uninterrupted—a condition known as status eclampticus. Almost all eclamptic seizures are preceded by preeclampsia; as with epileptic seizures, “auras” may act as a prodrome of the seizure. The causes of the seizure are undoubtedly several, including reduced blood flow to the brain as a result of arterial spasm and small emboli, cerebral edema possibly caused by excessive fluid retention, and bleeding from small arteries ruptured by the elevated blood pressure. Although conventional anticonvulsants (diazepam and phenytoin) were the drugs of choice, recent trials have demonstrated that magnesium sulfate is best at preventing further seizures, and it may also save more lives.

Parturition

neonatal homeostasis

labor abnormalities

uterine myometrial changes

inhibition by progesterone

stimulation

stretching

estrogen

oxytocin

prostaglandins PGE₂, PGF₂α

labor stages

1. cervical dilatation

2. expulsion of the neonate

episiotomy

Cesarean section

VBACS ¹

3. delivery of the placenta

4. recovery

placental abnormalities

placenta accreta

placenta increta

placenta percreta

placenta previa

total placenta previa

partial placenta previa

marginal placenta previa

low-lying placenta previa

uterine involution

Lactation

breast development

growth of the ductal system [estrogens]

development of the lobule-alveolar system [progesterone]

initiation of lactation

prolactin

estrogen and progesterone

hypothalamic control of prolactin

PIF

PRF

suppression of female sexual cycle during nursing

ejection of milk (milk let-down)

oxytocin

myoepithelial cells

maternal metabolic drain from lactation

Special considerations of the neonate

circulatory system adjustments

loss of blood flow through placenta increases SVR

PVR decreases

closure of foramen ovale

closure of ductus arteriosus

closure of ductus venosus

respiratory system

blood volume

cardiac output

arterial pressure

blood characteristics

neonatal jaundice (icterus neonatalis)

fluid, acid-base balances

liver function

bilirubin conjugation

plasma proteins

gluconeogenesis

hemostatic factors

digestion, absorption, and metabolism

metabolic rate and body temperature

nutritional needs

immunity

endocrine problems

prematurity

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