stages of labour

Normal labour:
Definition of labour:
Labor is defined as the onset of a sequence of painful regular uterine
contractions that results in progressive effacement and dilatation of the
cervix with descent of the presenting part and voluntary bearing-down
efforts leading to the expulsion of the products of conception through the
vagina.
There are some terms and definitions: read them
in (obstetrics by ten teachers): attitude, caput saccedaneum, effacement of the
cervix, engagement, position, presenting part, partogram, show, station, term,
vertex, synclitism.
Physiologic Preparation for Labor:
Prior to the onset of true labor, several preparatory physiologic changes
commonly occur. The settling of the fetal head into the brim of the pelvis,
known as lightening, usually occurs 2 or more weeks before labor in first
pregnancies. In women who have had a previous delivery, lightening
often does not occur until early labor. Clinically, the mother may notice a
flattening of the upper abdomen and increased pressure in the pelvis. This
descent of the fetus is often accompanied by a decrease in discomfort
associated with crowding of the abdominal organs under the diaphragm
(eg, heartburn, shortness of breath), and an increase in pelvic discomfort
and frequency of urination.

During the last 4–8 weeks of pregnancy irregular, generally painless
uterine contractions occur with slowly increasing frequency. These
contractions, known as Braxton Hicks contractions, may occur more
frequently, sometimes every 10–20 minutes, and with greater intensity
during the last weeks of pregnancy. When these contractions occur early
in the third trimester, they must be distinguished from true preterm labor.
Later, they are a common cause of "false labor," which is distinguished
by the lack of cervical change in response to the contractions.
During the course of several days to several weeks before the onset of
true labor, the cervix begins to soften, efface, and dilate. In many cases,
when labor starts, the cervix is already dilated 1–3 cm in diameter. This is
usually more pronounced in the multiparous patient, the cervix being
relatively more firm and closed in nulliparous women. With cervical
effacement, the mucus plug within the cervical canal may be released.
When this occurs, the onset of labor is sometimes marked by the passage
of a small amount of blood-tinged mucus from the vagina known as
bloody show.
Stages of labour
Normal labor is a continuous process that has been divided into three
stages for purposes of study, with the first stage further subdivided into
two phases, the latent phase and the active phase. The first stage of labor
is the interval between the onset of labor and full cervical dilatation.
The duration of the first stage of labor in primipara patients is noted to
range from 6–18 hours, while in multiparous patients the range is
reported to be 2–10 hours. The lower limit of normal for the rate of
cervical dilatation during the active phase is 1.2 cm per hour in first
pregnancies and 1.5 cm per hour in subsequent pregnancies.




The second stage is the interval between full cervical dilatation and
delivery of the fetus.
The duration of the second stage in the primipara is 30 minutes to 3
hours, and is 5–30 minutes for multiparas.
The third stage of labor is the period between the delivery of the fetus
and the delivery of the placenta. the duration of the third stage is 0–30
minutes for all pregnancies.
Separation of the placenta generally occurs within 2–10 minutes of the
end of the second stage, but it may take 30 minutes or more to
spontaneously separate. Signs of placental separation are: (a) a fresh
show of blood from vagina, (b) the umbilical cord lengthens outside the
vagina, (c) the fundus of the uterus rises up, and (d) the uterus becomes
firm and globular.
MANAGEMENT OF LABOU:
1- ADMISSION ASSESSMENT:
When a pregnant woman started labour or when she has spontaneous
rupture of membranes at term she should be admitted and full assessment
of her condition is accomplished.
To start with: FULL HISTORY ON ADMISSION about the
The frequency, strength and duration of her contractions and when they
began
Is there any history of watery vaginal discharge or bleeding, and ask
about the colour and amount of the amniotic fluid lost if there is SROM.
Details of her past obstetrical history, mode of deliveries, any history of
delivering big baby? C/S
LMP, GA , ask her about her ANC (it is better if she is bringing her
ANC card with her), any problem during the current pregnancy (medical
or obstetrical) like PIH, APH or reduction in the fetal activity or IUGR.
Ask her about the recent activity of her fetus.

Then we PROCEED FOR EXAMINATION of the woman
General examination, her vital signs: BP, temp., PR,
Then abdominal examination: for any previous scars,
Leopold s maneuvers are a series of four abdominal palpations of the
gravid uterus that can be used to ascertain fetal lie, presentation, and
estimated weight.

The fundus is palpated to ascertain the presence or absence of a fetal pole
(longitudinal or transverse lie) and the nature of the fetal pole (cephalic or
breech).
The lateral walls of the uterus are examined using one hand to palpate
and the other to fix the fetus. In longitudinal lies, the lateral uterus is
usually occupied by the fetal spine (long, firm, and linear) and small parts
or extremities.
The nature and station of the presenting part is determined by palpating
above the symphysis pubis.
If the presentation is vertex, the cephalic prominence is palpated to
determine the position of the fetal head. If the head is well flexed, neither
chin nor occiput will be prominent.
also assess the engagement which is an important sign for good progress
of labor, unengaged head should raise the suspicion of malposition or
deflexed head or may be any abnormality in the pelvis that prevent the
descent of the presenting part like a uterine fibroid, ovarian mass or
placenta previa.
In case of deeply engaged head then the head can not be felt by
abdominal examination (rule of five fifths) and it is called to be in zero
station while if you can feel the whole of the head suprapubically it is
called to be floating head which is a bad sign, if only two fifths of the
fetal head can be palpated abdominally so the head is engaged .
Assessment of the uterine contractions is performed by direct abdominal
palpation for at least ten minutes to count the number of contractions,
strength and frequency during these ten minutes.
Also FHR should be checked at the start by a pinard stethoscope or
sonicaid to prove viability and exclude fetal compromise.
Vaginal examination after taking her consent, we have to explain the
purpose and technique of the procedure for the patient:
Then the index and middle fingers are passed to the top of vagina and
cervix gently to assess the dilatation of the cervix digitally in centimeters
(if the cervix is not palpable this means 10 cm dilatation), effacement by
% of the cervical canal length which is normally 3 cm at 36 weeks of
gestation (if I find it 1.5 cm I can say that it is 50% effaced).


If the cervix is 3 cm dilated or more the position of the presenting part
can be assessed, the position is defined by the relation of the land mark or
the denominator of the presenting part to the maternal pelvis as in vertex
presentation the occiput must be determined if it is (RT or LT) occipito-
transverse, or if it is in oblique position like the( RT or LT) occipito-
anterior, or the (RT or LT) occipito- posterior when the occiput related to
the RT sacroiliac joint or the LT one respectively.
(positions)

The occiput can be identified by vaginal examination if the patient has
ruptured membranes, by identifying the posterior fontanel(triangular),
failure to find the posterior fontanel may be due to deflexed head or due
to caput which is the edema of the presenting part which obscure the
landmarks during examination.
If there is ruptured membranes the color and amount of the coming fluid
should be assessed if large amount of clear fluid or scanty with blood or
meconeum staining which is a warning sign of fetal distress.