Throughout the antenatal period, cervical examinations were complemented by assessments of cervical consistency, effacement, and fetal station to provide a comprehensive evaluation of cervical readiness for labor and delivery. At 39 weeks gestation, the patient spontaneously entered labor, and cervical examination revealed complete effacement and dilation to 4 centimeters, consistent with active labor. The patient progressed through the stages of labor and delivered a healthy infant via uncomplicated vaginal delivery.

1. Dr / Ahmed Salah Ashour(Ph.D.)
Associate professor of human anatomy
Dr.Ahmedashour@gmu.ac.ae
USMLE Clinical Anatomy

2. Case report

3. A 27-year-old primigravida presented
to our obstetrics clinic at 12 weeks
gestation for her first prenatal visit.
Transvaginal ultrasound examination
revealed a closed cervix with a
measured circumference of 3.5
centimeters.
Serial cervical assessments were
performed at regular intervals during
subsequent antenatal visits to monitor
cervical length and circumference.
Normal views of a closed internal os (arrow)

4. At 24 weeks gestation, the patient's
cervical circumference had increased
to 4.2 centimeters, consistent with the
physiological softening and dilation of
the cervix observed in mid-pregnancy.
As pregnancy progressed, cervical
circumference continued to gradually
increase, reaching 5.8 centimeters at 36
weeks gestation, indicative of cervical
ripening in anticipation of labor.
Fetal membranes into cervical canal

5. Throughout the antenatal period, cervical
examinations were complemented by
assessments of cervical consistency,
effacement, and fetal station to provide a
comprehensive evaluation of cervical
readiness for labor and delivery.
At 39 weeks gestation, the patient
spontaneously entered labor, and cervical
examination revealed complete
effacement and dilation to 4 centimeters,
consistent with active labor. The patient
progressed through the stages of labor
and delivered a healthy infant via
uncomplicated vaginal delivery.

6. ANATOMICAL
CHANGES
DURING
PREGNANCY

7. ILOs
• Awareness of anatomical changes aids in identifying potential complications
during pregnancy.
• For instance, changes in cardiovascular anatomy contribute to physiological
adaptations but also increase the risk of conditions like preeclampsia or
venous thromboembolism, necessitating vigilant monitoring and timely
interventions.

8. Anatomical changes during pregnancy are
significant for several reasons, especially from a
clinical perspective. Overall, anatomical changes
during pregnancy are not only normal but also
essential for the health and well-being of both
mother and baby. By recognizing the clinical
importance of these changes, clinicians can provide
better care and support to pregnant women
throughout their pregnancy journey.
Understanding the clinical importance of anatomical
changes during pregnancy is essential for providing
comprehensive prenatal care, identifying and
managing pregnancy-related complications, and
ensuring the health and well-being of both the
pregnant individual and the fetus.

10. 1-
Changes in
reproductive
organs

11. Uterus

12. Uterine weight:
During pregnancy, the uterus increases in
weight from 60 to 1000g. By the end of
pregnancy, the uterus can weigh
anywhere from around 900 to 1,000
grams or even more.
This increase in weight is due to:
• Growth and development of the fetus,
• Placenta
• Amniotic fluid (1 liter)
• Expansion of the uterine muscle and
supporting tissues.

13. Uterine length:
The uterine length increases from 6.5 to 32 cm. In a non pregnant state, the uterus is
situated in the pelvic cavity. As the uterus enlarges, it gradually expands out of the
pelvic cavity and into the abdominal cavity. By the third trimester of pregnancy, the
top of the uterus, known as the fundus, typically reaches up to the level of the
mother's rib cage or even higher.

14. Uterine location:
During pregnancy, uterus expands into the
abdominal cavity.
The expansion of the uterus into the
abdominal cavity can sometimes cause
discomfort or pressure on the abdominal
organs, leading to symptoms such as:
• Shortness of breath
• Indigestion
• Changes in bowel habits.

15. Uterine histological architecture:
In addition to the growing foetus, uterine expansion is caused by an increase in
connective tissue and in the size and number of blood vessels supplying the uterus
(hypertrophy + hyperplasia ).

16. Uterine ligamentous supports

17. During pregnancy, uterine ligaments
become elongated and hypertrophied.
This facilitate the uterus in its move from
the pelvic cavity into the abdominal
cavity.
The elongation and hypertrophy of the
uterine ligaments help to support the
increasing weight of the uterus and
provide flexibility for its movement
within the pelvis and later into the
abdominal cavity preventing IVC
compression.

18. IVC compression
Compression of the IVC can occur, particularly in
the later stages of pregnancy when the uterus is
larger and occupies more space within the
abdominal cavity.
To alleviate IVC compression and improve blood
flow, pregnant women are often advised to avoid
lying flat on their backs, especially in the later
stages of pregnancy. Instead, they are encouraged
to lie on their side, which helps to relieve pressure
on the IVC and allows for better blood circulation
to the heart and placenta.
IVC
Clinical Insight

19. Pregnant women are encouraged to lie on their side
Clinical Insight

20. Cervix

21. During pregnancy, the cervix undergoes
several changes to support and protect the
developing fetus.
One of these changes is the closure of the
cervix, which helps to seal off the uterus
from the vaginal canal and external
environment.

22. Additionally, a mucus plug forms over
the cervix during pregnancy, further
sealing off the cervical canal.
Mucus plug helps to prevent bacteria and
other pathogens from entering the uterus
and potentially causing harm to the fetus.

23. If the cervix begins dilating prematurely,
it is sometimes stitched together during
the second trimester, until the foetus in
mature.
This procedure is known as a cerclage.
Clinical Insight

24. Vagina

25. Vaginal blood flow
The increased levels of hormones, especially estrogen, during pregnancy can lead to
increased blood flow to the pelvic area, including the vagina. This can cause the
vaginal tissues to become more engorged and sensitive.

26. Vaginal discharge:
It's common for pregnant women to
experience an increase in vaginal
discharge, known as leukorrhea.
This discharge is typically thin, milky-
white, and odorless. It helps to protect
the birth canal from infection and keeps
the vagina clean.

27. Vaginal pH:
The pH balance of the vagina may
change during pregnancy, which can
affect its acidity levels.
This change can make pregnant women
more susceptible to vaginal infections
such as yeast infections or bacterial
vaginosis.

28. Vaginal size and shape:
As the pregnancy progresses, the vagina may
undergo changes in size and shape to
accommodate the growing fetus.
This can include stretching and widening of the
vaginal canal, particularly during childbirth.

29. 2-
Changes in
respiratory
system

30. During pregnancy, the body is in a state of hyperventilation due to high level of
progesterone. Breathing becomes more costal than abdominal. Additionally, most
women are mouth breathers during pregnancy. The diaphragm is progressively
elevated. Possibly because of expansion and elevation of the rib cage.

31. 3-
Changes in
endocrinal
system

32. Relaxin is a hormone secreted by the corpus luteum of pregnancy. Relaxin softens
connective tissue during pregnancy in preparation for labour and delivery.
Other major hormones effecting a woman during pregnancy include estrogen,
progesterone.

33. Edema is present in the hands. feet. face and eyelids during pregnancy. This is due
in part to sodium and water retention. Additionally. hormones circulating by the
placenta. ovaries, and adrenal cortex cause increased capillary permeability, which
contributes to the edema many pregnant women experience.

34. 4-
Changes in
musculoskele
tal System

35. Muscular changes

36. Abdominal muscles are stretched to the point of their elastic limit by the end of
pregnancy.
The pelvic floor muscles must withstand the weight of the uterus, the floor drops as
much as 2.5 cm.

37. Postural changes

38. During pregnancy, postural changes occur to accommodate for abdominal growth
and center of gravity changes. These changes include forward head, increased
lumbar lordosis, hyperextended knees.

39. Bones and joints changes

40. There is tendency to decalcification of bones, sublaxation of joints due to softening
of ligaments by relaxin hormone. It is more marked in sacroiliac joint and
symphysis pubis, leading to waddling gait (duck-like walk).

41. 5-
Changes in
cutaneous
system

42. Overstretching of the skin:
Due to overstretching of the skin, the
elastic fiber may rupture together with
small blood vessels and so red streaks
appear; known as striae gravidarum.
They are usually more marked below the
umbilicus, on the breasts and may appear
on the buttocks and thighs.
After labour, the red striae become pale
silvery white due to fibrosis and are
known as (striae albicantes).

43. Pigmentation of skin:
It is due to suprarenal changes; it usually begins to appear after the 4th month. The
pigmentation may appear anywhere, but the commonest sites are:
1. Below the umbilicus: Linea nigra is a line of pigmentation in the midline.
2.Face: Cloasma gravidarum or mask face of pregnancy which is butterfly
pigmentation of the forehead, nose, upper lip and the adjoining parts of the checks.
Linea nigra Cloasma gravidarum Cloasma gravidarum

44. 6-
Changes in
maternal
weight

45. The average weight gain for primi-gravidae
is 12.5 Kg. and is probably about 0.9 Kg.
less for multigravidae.
Weight gain is produced by:
• Fetus 3.63-3.88 Kg
• Placenta 0.48-0.72 Kg
• Amniotic fluid 0.72-0.97 Kg
• Uterus and breasts 2.42-2.66 Kg
• Blood and fluid 1.94-3.99 Kg
• Muscle and fat 0.48-2.91 kg

46. 6-
Changes in
nervous
system

47. Pregnancy-related anatomical changes,
such as alterations in spinal curvature
and nerve compression due to the
growing uterus, can contribute to
neurological symptoms such as
• Back pain
• Sciatica.

48. Functional changes may appear especially in neurotic women as :
• Sleepy, depressed
• Excited and suffer from insomnia.
• Nausea and vomiting
• Change of appetite such as refusal of some types of food.
• Neuralgias
Sleepy Insomnia Nausea and vomiting

49. 7-
Changes in
internal organs’
anatomical
location

50. During pregnancy, the growing fetus and
uterus can cause a shift in the position of
internal organs, a phenomenon often
referred to as "visceral shift."
This shift occurs to accommodate the
expanding uterus and to make room for
the growing baby.
Generally, organs such as the bladder,
intestines, stomach, and liver may be
affected by the upward and outward
pressure of the expanding uterus.

51. Visceral shift during pregnancy can sometimes lead to digestive discomfort, such as
heartburn, indigestion, or constipation. This is because the displacement of organs
can affect their function and may cause changes in gastrointestinal motility and
pressure on the stomach and intestines.
Heartburn

52. The upward displacement of the diaphragm due to the expanding uterus can also
impact respiratory function. Some pregnant women may experience shortness of
breath or difficulty breathing, especially in the later stages of pregnancy when the
uterus is larger. Breathing exercise would be helpful.

53. The growing uterus can put pressure on the bladder, leading to increased frequency
of urination. Some women may also experience urinary urgency or leakage due to
the pressure exerted on the bladder.

54. Formative Quiz

55. Q1 A 28-year-old primigravida presented to our obstetrics clinic at 24 weeks
gestation with complaints of dysuria, frequency, and suprapubic discomfort for the
past three days. She denied fever, chills, or flank pain. On examination, her vital
signs were within normal limits, and abdominal examination revealed a gravid
uterus consistent with the gestational age. Urinalysis demonstrated significant
pyuria and bacteriuria, suggestive of a urinary tract infection. Which anatomical
change during pregnancy contributes to an increased risk of urinary tract infections
(UTIs)?
a) Enlargement of the uterus
b) Relaxation of pelvic ligaments
c) Compression of the bladder by the growing uterus
d) Elevation of the diaphragm

56. Q2 A 25-year-old woman presented to our obstetric clinic for her first prenatal visit
at eight weeks gestation. She reported regular menstrual cycles and a history of
good health. Obstetric examination revealed a healthy primigravida with no
significant medical or surgical history. Initial laboratory investigations, including
complete blood count, blood typing, and screening for infectious diseases, were
within normal limits. The patient received comprehensive prenatal counseling
regarding nutrition, exercise, prenatal vitamins, and warning signs of potential
complications. Serial ultrasounds confirmed the normal progression of fetal growth
and development. What anatomical adaptation during pregnancy helps prepare the
mother's body for labor and delivery?
a) Enlargement of the breasts
b) Softening and dilation of the cervix
c) Decreased cardiac output
d) Reduced blood volume

57. Q3 A 30-year-old primigravida presented to our obstetrics clinic at 28 weeks
gestation with complaints of pelvic discomfort and difficulty ambulating. Physical
examination revealed an exaggerated waddling gait. Pelvic examination
demonstrated symphyseal tenderness upon palpation. Which anatomical change is
responsible for the characteristic "waddling" gait seen in this pregnant female?
a) Pelvic ligament relaxation
b) Uterine enlargement
c) Increased blood volume
d) Elevation of the diaphragm

58. Q4 A 32-year-old pregnant woman presented to our obstetrics clinic at 20 weeks
gestation with complaints of episodic facial flushing and sensation of heat in her
face. She reported no associated symptoms such as itching, swelling, or systemic
symptoms. Physical examination revealed transient erythema of the cheeks and
forehead during episodes of flushing, with no evidence of rash or urticaria.
Anatomical changes in which organ system are primarily responsible for the
cardiovascular adaptations observed during pregnancy?
a) Respiratory system
b) Musculoskeletal system
c) Urinary system
d) Cardiovascular system

59. Q5 A 23-year-old primigravida presented to the labor and delivery unit at 32 weeks
gestation with complaints of lower abdominal cramping and intermittent
contractions for the past 12 hours. Obstetric examination revealed regular uterine
contractions every 5 minutes, cervical dilation of 2 centimeters, and effacement of
50%. Fetal monitoring demonstrated reassuring heart rate tracings with no signs of
distress. Which anatomical adaptation is essential for accommodating the growing
fetus and preventing premature labor?
a) Enlargement of the breasts
b) Softening and widening of the pelvic bones
c) Compression of the bladder by the uterus
d) Elevation of the diaphragm

60. Q1. Compression of the bladder by the growing uterus
Q2. Softening and dilation of the cervix
Q3. Pelvic ligament relaxation
Q4. Cardiovascular system
Q5. Softening and widening of the pelvic bones

61. List of Texts and Recommended Readings
• Last's Anatomy, Regional and Applied. Chummy S. Sinnatamby. 12th edition 2011, ISBN:13 - 978 0 7020
3394 0 (Available in ClinicalKey: https://www.clinicalkey.com/#!/browse/book/3-s2.0- C2009060533X)
• Estomih Mtui, Gregory Gruener and Peter Dockery. Fitzgerald's Clinical Neuroanatomy and
Neuroscience. 7th edition; 2016, ISBN: 13 - 978-0-7020- 6727-3 (Available in ClinicalKey:
https://www.clinicalkey.com/#!/browse/book/3-s2.0- C20130134113
• Drake, Richard L. Gray's Anatomy for Students, Third Edition, Elsevier Saunders 2015. ISBN-13: 978-
0702051319 (Available in ClinicalKey: https://www.clinicalkey.com/#!/browse/book/3- s2.0-
C20110061707).
• Sobotta Atlas of Human Anatomy. F. Paulsen. Vol.1, 15th Edition; 2013, ISBN: 9780702052514 (Available in
ClinicalKey: https://www.clinicalkey.com/#!/content/book/3- s2.0-B9780702052514500067)
• Sobotta Atlas of Human Anatomy. F. Paulsen. Vol.2, 15th Edition; 2013, ISBN:13 - 978-0-7020-5252-1

62. https://www.slideshare.net/ahmedsahm
edtanta
USMLE FULL SOURCES

63. Recap