Disorders of early pregnancy

Question 1

What is the physiology of early pregnancy?

Answer 1

• Oocyte is fertilised in the ampulla of fallopian tube- forms a zygote, swept towards uterus by ciliary action and peristalsis
• Enters uterus around day 4 as a multicellular morula
becomes blastocyst by developing fluid-filled cavity
• Outer layer trophoblast invade the endometrium to implant between day 6-12- this layer forms the placenta, 15% of embryos are lost at this stage

Question 2

What happens once the trophoblast is formed?

Answer 2

• Trophoblasts produce hCG, which peaks at 12 weeks- maintains corpus luteum, which produces oestrogen and progestogen, these hormones turn secretory endometrium into decidua (rich in glycogen and lipids)
• Trophoblastic proliferation leads to formation of chorionic villi on the endometrial surface of the embryo-
forms the surface area for nutrient transfer in the cotyledons of the placenta
• Placenta morphology is complete at 12 weeks- a heartbeat is established at day 22 and visible on transvaginal ultrasound a week later

Question 3

What is a spontaneous miscarriage?

Answer 3

when a foetus dies or delivers dead before 24 completed weeks of pregnancy-
the majority occur before 12 weeks
• 15% of clinically recognised pregnancies spontaneously miscarry
Rate of miscarriage increases with age

Question 4

What can cause miscarriages?

Answer 4

• Isolated non-recurring chromosomal abnormalities account for >60% of ‘one-off’ or sporadic miscarriage
however, if >3 miscarriages occur, then recurrent causes are more likely

Question 5

How does a miscarriage present?

Answer 5

presents with bleeding
pain from uterine contractions can cause confusion with ectopic pregnancy
uterine size and state of cervical os determine what type of miscarriage
severe uterine tenderness is abnormal

Question 6

What does an USS show in a miscarriage?

Answer 6

show if a foetus is in the uterus and viable
detect retained foetal products
if any doubt, women should be rescanned in 1 week as very early pregnancy can be confused with non-viable pregnancy
• USS does not always show ectopic pregnancy
but if foetus is seen in uterus a concurrent ectopic pregnancy is very unlikely
sometimes very difficult to differentiate between an early viable or failed intrauterine pregnancy, a complete miscarriage or an ectopic pregnancy- assume ectopic until location is determined

Question 7

How are hCG levels used in miscarriage?

Answer 7

blood levels normally increase >63% in 48hrs with a viable intrauterine pregnancy
a decline in hCG of >50% suggests a non-viable pregnancy
a change in hCG over 48hrs between a 50% decline and 63% rise suggest an ectopic pregnancy

Question 8

When is admission required for an ectopic pregnancy?

Answer 8

if the women is symptomatic, if the miscarriage is septic or if there is heavy bleeding
resuscitation is sometimes needed as products of conception in cervical os can cause pain, bleeding and vasovagal shock
they are removed using a speculum and polyp forceps

Question 9

What does IM ergometrine do?

Answer 9

reduce bleeding by contracting the uterus, but only used if foetus is non-viable- if fever, then swabs and IV antibiotics given

Question 10

What should rhesus negative women be given if they have a miscarriage?

Answer 10

should be given anti-D if the miscarriage is treated surgically or medically, or if there is bleeding >12 weeks- reduces risk in future pregnancies
• 90% of women in whom foetal heart activity is detected at 8 weeks will not miscarry

Question 11

What are the types of miscarriage?

Answer 11

• Threatened miscarriage- bleeding, but the foetus is alive, the uterus is of expected size and the cervical os is closed- 25% will go on to miscarry
• Inevitable miscarriage- bleeding is heavier-foetus may still be alive, cervical os is open- miscarriage is about to occur
• Incomplete miscarriage-some foetal parts have been passed, but the os is usually open
• Complete miscarriage- all foetal tissue has been passed- bleeding has diminished, the uterus is no longer enlarged and the cervical os is closed
Septic miscarriage- contents of the uterus are infected causing endometritits- vaginal loss is offensive, uterus is tender, but fever may be absent, if pelvic infection occurs there is abdominal pain and peritonism
• Missed miscarriage- the foetus has not developed or died in utero, this is not recognised until bleeding occurs or USS is performed- uterus is smaller than expected and os is closed

Question 12

What is the expectant management for a non-viable pregnancy?

Answer 12

can be continued as long as the woman is willing and there are no signs of infection
it is successful within 2-6 weeks in >80% of women with incomplete miscarriage and in 30-70% of women with missed miscarriage
a large intact sac is associated with lower success rates

Question 13

What is the medical management for a non-viable pregnancy?

Answer 13

vaginal or oral prostaglandin (misoprostol)
it is successful in >80% of women with incomplete miscarriage and 40-90% of women with missed miscarriage
urine pregnancy test should be repeated 3 weeks after to exclude an ectopic or molar pregnancy

Question 14

What is the surgical management for a non-viable pregnancy?

Answer 14

surgical management of miscarriage (SSM) was previously known as ERPC
carried out under GA using vacuum aspiration
suitable if the women prefers it, there is heavy bleeding or signs of infection
success rate are >95% for both incomplete and missed miscarriage- tissue is examined to exclude molar pregnancy

Question 15

What are the complications of the management for miscarriages?

Answer 15

o Vaginal bleeding in expectant or medical management may be heavy and painful- may need surgical management (10-40%)
o Infection (3%) are similar across all managements
o Surgical management can partly remove the endometrium causing Asherman’s syndrome, or
perforate the uterus (<1%)

Question 16

What is recurrent miscarriage?

Answer 16

• Recurrent miscarriage is when 3 or more miscarriages occur in succession
1% of couples are affected, but chance of miscarrying in 4th pregnancy is still only 40%
• In early-pregnancy ultrasound monitoring is very important
in later pregnancy, ‘high-risk’ monitoring is
important because late pregnancy complications are more common

Question 17

What are antiphospholipid antibodies?

Answer 17

thrombosis in the uteroplacental circulation is likely to be the mechanism
treatment is with aspirin and LMW heparin

Question 18

What are parental chromosomal defects?

Answer 18

foetal miscarriage tissue is karyotyped
if shows an unbalanced abnormality then parental karyotyping is performed
refer to clinical geneticist- CVS and amniocentesis is offered, donor oocytes or sperm is an option or PGD of IVF embryos are alternatives

Question 19

Which anatomical factors can causes recurrent miscarriage?

Answer 19

uterine abnormalities are diagnosing with USS, MRI or hysterosalpingogram- more common
often incidental finding and surgical intervention may leads to uterine weakness or adhesion formation
cervical problems contribute to late miscarriage as well as preterm labour

Question 20

What are the other causes of recurrent miscarriage

Answer 20

Infection- late miscarriage 
Hormonal factors- thyroid dysfunction (thyroid antibodies) is associated with recurrent miscarriage, so should be tested and treated- PCOS may be associated with an increased risk of pregnancy loss
o	Obesity
o	Smoking
o	Excess caffeine intake
o	Older maternal age