Emergency Obstetrics Flashcards
Labour - First Stage
Regular uterine contractions plus cervical change (dilation and effacement). The first stage of labour includes the latent and active phases.
Labour - first stage
Latent phase
Latent phase
- The presence of uterine activity resulting in progressive effacement and dilation of the cervix proceeding to the active phase. It is complete when a nulliparous woman reaches 4 cm dilation and a parous woman reaches 4 - 5 cm. Cervical length should be less than 1 cm.
Labour - first stage
Active phase
Active phase
- The presence of a pattern of contractions leading to cervical effacement and dilatation after 4 cm dilatation in a nulliparous woman or 4 - 5 cm dilatation in a parous woman.
Labour - second stage
Full dilation to delivery of the baby
- Passive second stage - full dilation without active pushing
- Active second stage - full dilation with active pushing
Labour - third stage
Immediately after delivery of the baby to delivery of the placenta
Labour - fourth stage
Immediately after delivery of the placenta to one hour postpartum
Dystocia
Delayed or arrested progress in labour, irrespective of cause
- In active first stage, greater than 4 hours of < 5 cm per hour dilatation, or No cervical dilatation over 2 hours
- In active second stage, greater than 1 hour of active pushing withou descent of the presenting part
Gravidity
The total number of pregnancies regardless of duration and outcome.
- Gravidity refers to a uterus that contains a fetus, whatever the outcome (ie abortion, stillbirth, or live birth)
- We classify women according to the number of times her uterus has been occcupied (gravidity)
Parity
The number of pregnancies completed to delivery during the viable period.
- Parity refers to delivery of a infant after the 28th week of gestation, irrespective of whether the infant was born alive or dead
- We classify woman according to the number of times she has carried a fetus more than 28 weeks (parity)
Grand mutiparity
Definition
Refers to a woman who has had 5 or more births
What are the four distinct classification of Parity?
T-P-A-L
- Term Infants
- Preterm infants
- Abortions
- Children Current Living
Perinatal period
The interval between the birth of an infant born after 20 weeks gestation and the 28 completed days after birth.
Birth
The complete expulsion or extraction from the mother of a fetus after 20 weeks gestation.
In the absence of accurate dating criteria, fetuses weighing < 500 g are usually not considered as births but rather are termed abortus
Birthweight
The weight of a neonate determined immediately after delivery or soon thereafter as feasible. It should be expressed to the nearest gram.
Live Birth
The term used to record a birth whenever the newborn after birth breathes sponstaneously or shows any other sign of life such as a heartbeat or definite spontaneous movement of voluntary muscles.
Stillbirth or Fetal death
The absence of signs of life at or after birth
Early Neonatal Death
Death of a liveborn neonate during the first 7 days after birth
Late Neonatal Death
Death after 7 days but before 29 days
Low birthweight
A newborn whose weight is < 2500g
Very low birthweight
A newborn whose weight is < 1500g
Extremely low birthweight
A newborn whose weight is < 1000g
Term neonate
A neonate born any time after 37 completed weeks of gestation and up until 42 completed weeks of gestation ( 260 - 294 days)
American College of Obstetricians and Gynecologists
- Early term refers to neonates born at 37 completed weeks up to 38 weeks
- Full term denotes those born at 39 completed weeks up to 40 weeks
- Late term denotes those born at 41 completed weeks
Preterm neonate
A neonate born anytime before 37 completed weeks (259th day)
Postterm neonate
A neonate born anytime after completion of the 42nd week, beginning at day 295
Abortus
A fetus or embryo removed or expelled from the uterus during the first half of gestation - 20 weeks or less, or in the absence of accurate dating criteria, or weighing < 500g
Induced termination of pregnancy
The purposeful interruption of an intrauterine pregnancy that has the intention other than to produce a liveborn neonate and that does not result in a live birth.
Primigravida
A woman who is pregnant for the first time
Primipara
A woman who has had only one delivery
Multigravida
A woman who has had two or more pregnancies irrespective of the outcome
Multipara
A woman who has had two or more deliveries
- A woman who has had more than five deliveries is referred to as a “grand mutipara”
Nullipara
A woman who has never delivered
Pregnancy is divided into three trimesters
What are they?
First Trimester
conception to 14 weeks
Second Trimester
14 - 28 weeks
Third Trimester
28 - 42 weeks
What is the normal duration of pregnancy?
40 weeks
List the key physiologic changes during pregnancy
How does blood volume change in pregnancy?
- Average woman has 4 - 5 litres of total blood volume
- Pregnancy causes blood volume to increase throughout gestation with a 40 - 50% increase by term
- This increase in blood volume is neccessary to meet the metabolic needs of the fetus, to adequately perfuse maternal organs such as the uterus and kidneys and to help compensate for blood loss during delivery
How much blood volume does the uterus contain at term?
- 15 - 16 % of the mothers circulating blood volume
- During vaginal delivery a woman may have as much as 500 ml of blood loss
How does pregnancy change red blood cell volume?
- As blood volume increases so does the number of red blood cells (RBCs), which increase by as much as 33% over the normal count
- The increase in RBCs heightens the pregnant woman’s need for iron, which is why most women have to take prenatal vitamins or iron supplements
- If the woman does not take iron the fetus can deplete maternal iron stores for its needs, resulting in iron deficiency
How does the White blood Cell Count change during pregnancy?
- WBC increases from an average of 4300 cells/ul before pregnancy to as high as 12000 cell/ul or more by the third trimester.
- Clotting factors are similarly increased while fibrinolytic factors are depressed
- These are important factors to consider if you are dealing with obstetric hemorrhage or thrombolic disease
How does the heart change during pregnancy?
- Increases in size by 10 - 15% with a collateral capacity increase of 70 - 80 ml
- Cardiac output increases by 40% by 22 weeks gestation
- As the uterus enlarges the myocadium is displaced upward to the left whch can cause a benign systolic flow murmur
How does heart rate and ECG change during pregnancy?
- Heart rate increases to 15 - 20 beats/min by term
- ECG changes may include ectopic beats and supraventricular tachycardia
- Slight left axis deviation and lead III changes such as low-voltage QRS, T wave inversion or flattening, or even occasional Q waves
How does preganancy affect a women’s sensitivity to body positioning?
- Resting or lying supine can cause the uterus to impinge upon the inferior vena cava, thereby decreasing venous return to the heart
- Pressure by the fetus on the common iliac vein creates this problem as well
- Overtime if pressure is not relieved, cardiac ouput is decreased, blood pressure drops, and lower extremity edema will result
What are some of the risks related to Venous distention in pregnancy?
- The pressures exerted upon the circulatory sytem and the increased blood volume combine to produce venous distension of about 150%
- Blood return to the heart is decreased as the venous ends of the capillaries become dilated
- Gravid women who are bedridden or who spend a great deal of time lying down can develop deep venous thrombosis, which can lead to pulmonary embolism