Maternity Notes

Increase in cardiac output during pregnancy

30 - 50% increase in cardiac output that peaks in trimester 3 due to a rise in estrogen levels.

Effect of progesterone on blood pressure in pregnancy

Progesterone mediates a drop in blood pressure by decreasing systematic vascular resistance.

Normal blood pressure change in the first trimester of pregnancy

A drop of 10-15 mmHg is normal in the first trimester.

Function of amniochorionic membranes

Provide protection for the fetus, maintenance of pregnancy, and signal to initiate labour.

Composition of amniotic fluid at 25 weeks of gestation

Contains increased concentrations of urea and creatinine due to fetal kidney function and decreased permeability of fetal tissues.

Polyhydramnios

Excess amount of amniotic fluid (over 2000ml), commonly associated with multiple pregnancies or fetal swallowing problems.

Oligohydramnios

Deficiency in amniotic fluid (less than 500ml), often associated with fetal renal problems.

Adaptations in fetal circulation

Include umbilical vein, ductus venosus, foramen ovale, ductus arteriosus, and umbilical artery.

Moulding of the fetal skull

The ability of the fetal skull to change shape during labour to aid passage through the birth canal.

Functions of the fetal skull

Protection of the brain and ability to change shape during labour.

Regions of the fetal skull identified during labour

Occiput, Vertex, Sinciput, Face, which guide midwives in assessing fetal head position.

Umbilical vein function during fetal development

Carries oxygenated blood from the placenta into the growing fetus.

Ductus arteriosus function

Connects the pulmonary arterial trunk to the descending aorta in fetal circulation.

Role of amniotic fluid in pregnancy

Protects the fetus, cushions from external impacts, allows symmetrical growth and maintains body temperature.

Sutures and fontanelles in the fetal skull

Gaps between bones that allow for overlapping during labour and prevent compression of the brain.