Manaia Health PHO19 March 2014

A miscarriage is a pregnancy loss due to natural causes before 20 weeks gestation

Embryo/fetal Causes◦ The embryo, fetus or placenta are abnormal;

there is early fetal demise followed by spontaneous expulsion of the pregnancy

Maternal Causes◦ The pregnancy is normal, but there is a maternal

medical disorder or complication causing fetal demise and/or expulsion of the pregnancy

Mostly sporadic genetic abnormalities Usually first trimester Occasionally chromosomal problems will

lead to fetal demise in the 2nd trimester (trisomy 21, 18, 13, triploidy, 45XO)

Sometimes a subchorionic haematoma may lead to 2nd trimester miscarriage, probably due to ascending infection

Early embryonic or fetal demise typically occurs at 4-8 weeks gestation

Trophoblast usually continues to function for 2-6 weeks and symptoms of pregnancy persist

Eventually trophoblast function declines and the uterus expels the pregnancy with a variable amount of pain and vaginal bleeding

Women with early pregnancy bleeding may have a viable or a non-viable pregnancy◦hCG measurements do not distinguish viable

from non-viable pregnancies If a viable pregnancy is seen on scan

miscarriage is very unlikely If a non-viable pregnancy is confirmed on

scan it is likely that fetal demise occurred several weeks prior to presentation

If a routine early pregnancy scan fails to confirm a viable pregnancy:1. This may be early fetal demise or 2. The scan may have been done too early

It is not possible to confirm early fetal demise if:◦ The mean gestational sac diameter is <25mm or◦ The CRL is <7mm

If in doubt it is usually best to manage expectantly and rescan after at least 1 week. hCG doesn’t help!

After fetal demise most pregnancies will miscarry completely. Interventions speed up the process but do not reduce average blood loss

Interventions available: 1. Medical – misoprostol (if already signs of mc) +/-

mifepristone (if no sign of MC)2. Surgical – dilatation & suction evacuation; this is

associated with a higher risk of infection and a risk of uterine perforation

These only cause a small minority of miscarriages.

1st trimester – anti-phospholipid syndrome, viral infections

2nd trimester – uterine abnormalities, cervical incompetence, fibroids

Definition:◦ 3 consecutive spontaneous 1st trimester losses◦ 2 consecutive spontaneous 2nd trimester losses

Affects about 1% of women trying to conceive

An underlying cause is only found in a minority

If there is an underlying cause it must be a parental abnormality

Maternal medical problems◦ Antiphospholipid syndrome

Balanced chromosomal translocation Abnormal uterus (congenital or acquired) – cone

biopsy, repeated or late TOP, childbirth trauma

If no cause found high chance of subsequent successful pregnancy.

Avoid empirical treatment; however reassurance scans in the 1st trimester increase the likelihood of a successful pregnancy