The document discusses the transitional period between the first and second stages of labor. It describes the physiological changes that occur as contractions become stronger and the cervix fully dilates. These include restlessness in the mother, rupture of membranes, and urges to push. As the fetal head descends, it displaces soft tissues in the pelvis. Several signs like expulsive contractions and appearance of the presenting part indicate transition to the active second stage of labor, but can only be confirmed by vaginal examination.

1. Rabi muhammad
S.P.B.M, UDUTH,
SOKOTO.

2. The second stage of labour
has traditionally been defined as the
phase between full dilatation of the
cervical os and the birth of the baby.
However, there is a transitional period
between the first stage of labour and the
actual time when active maternal pushing
efforts begin.

3. This period is typically
characterised by maternal
restlessness, discomfort, desire for
pain relief, a feeling that the process
is never ending and demands to
birth attendants to get the birth
process over as quickly as
possible.

4. The physiological changes
result from a continuation of the
same forces that have been at work
during the first stage of labour but
activity is accelerated once the
cervix has become fully dilated.
This acceleration, however, does
not occur abruptly, hence, it is a
process.

5. Contractions become stronger
and longer but may be less frequent,
allowing both mother and fetus to
rest in between contractions.
 The membranes often rupture
spontaneously towards the end of
the first

6. stage or during transition to the
second stage.
The consequent drainage of liquor
allows the fetal head to be directly
applied to the cervix, this pressure
aids distention.

7. Fetal axis pressure increases
flexion of the head, which results in
smaller presenting diameters, more
rapid progress and less trauma to
both mother and fetus.
The contractions become
expulsive as

8. the fetus descends further into the
vagina.
Pressure from the presenting part
stimulates nerve receptors in the
pelvic floor ( ferguson reflex ) and
the woman experiences the urge to
push.

9. This reflex may initially be
controlled to a limited extent but
becomes increasingly compulsive,
overwhelming and involuntary
during each contraction.
The mother then employs her
secondary

10. powers of expulsion i.e the
abdominal muscles and diaphragm
to push out the baby.
SOFT TISSUE DISPLACEMENT
The descending fetal head
displaces the soft tissues of the
pelvis.

11. Anteriorly, the bladder is pushed
upwards into the abdominal cavity
where it is at less risk of injury
during fetal descent.
This results in the stretching and
thinning of the urethra.

12. Posteriorly, the rectum becomes
flattened into the sacral curve and
the pressure of the advancing head
expels any residual faecal matter.
The levatoani muscles dilate, thin
out and are displaced laterally and
the perineal body is flattened,
stretched and

13. thinned.
The fetal head becomes visible at
the vulva, advancing with each
contraction and receding between
contractions until crowning takes
place.
The head is then born and the
shoulders

14. and body follow with the next
contraction accompanied by a gush
of amniotic fluid and sometimes
blood.
The second stage culminates in
the birth of the baby.

15. This is not clinically
apparent. Several of the
signs are presumptive and
can only be confirmed by
vaginal examination. These
include:
Expulsive uterine
contractions: Although
this is usually a sign that

16. the cervix is fully dilated, it is
possible for the woman to feel the
urge to push before full dilatation
occurs e.g opp, when rectum is full,
e.t.c.
Rupture of forewaters: This may
occur at anytime during labour but

17. physiologically, it occurs at the end
of 1st stage when cervix is fully
dilated and can no longer support
the bag of waters.
Dilatation & gaping of the anus:
As the fetal head descends and
touches the pelvic floor, there’s
increased pressure

18. especially on the rectum. This
results in dilatation and gaping of
the anus, the anus also pouts and
may result in discharge of faecal
matter.
Appearance of the presenting
part: Although this is usually
definitive, it is important to be
aware that excessive

19. moulding may result in the
formation of a large caput
succedaneum, which can protrude
through the cervix prior to full
dilatation. Similarly, a breech
presentation may be visible when
the cervix is not fully dilated.

20. Show: This is the loss of
bloodstained mucus which often
accompanies rapid dilatation
towards the end of 1st stage of
labour. It must be distinguished
from frank fresh blood loss caused
by partial separation of the
placenta, or that caused by
ruptured vasa praevia.

21. Congestion of the vulva: The
pressure of the fetal head on the
vulva results in venous congestion,
however, premature pushing may
also cause this.
 Appearance of rhomboid of
michaelas: This is a dome-shaped

22. curve in the lower back and is said
to indicate the posterior
displacement of the sacrum and
coccyx as the fetal head moves into
the maternal sacral curve. This
makes the mother to arch her back,
push her buttocks forward and
throw her arms back to grasp any
object. This sign

23. is often noted when a woman is in
an upright position where the back
is visible.
COMFIRMATORY EVIDENCE
This is only done by vaginal
examination which reveals no
cervix and it is done to:

24. Ensure the woman is not pushing
too early before the cervix is fully
dilated.
To provide a baseline for timing
the length of 2nd stage of labour.